cka

SURESH BISHOKARMA MS

MCH RESIDENT NEUROSURGERY

NINAS

FOURTH VENTRICLE

ANATOMY AND SURGICAL PERSPECTIVE

The fourth ventricle is a broad tent- shaped midline cavity located

between cerebellum and brainstem

It is lined by a membrane consisting of ependyma and a double fold of pia mater which

constitutes the tela choroidea of the fourth ventricle

COMMUNICATION

It has a roof a floor and two lateral recesses

The roof superior and inferior medullary velum and cerebellar

vermis

Apex tented into cerebellum

The upper part of the roof superior cerebellar peduncles and

the superior medullary velum (thin sheet of white matter)

The inferior part of the roof Inferior medullary velum (non-

nervous tissue) Medulloblastoma origin(Youman)

ROOF

FLOOR OF FOURTH VENTRICLE

Each inferolateral margin of the floor is marked by a narrow white ridge called taenia

The right and left taeniae meet at the inferior apex of the floor to form a small fold

called the obex

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

The fourth ventricle is a broad tent- shaped midline cavity located

between cerebellum and brainstem

It is lined by a membrane consisting of ependyma and a double fold of pia mater which

constitutes the tela choroidea of the fourth ventricle

COMMUNICATION

It has a roof a floor and two lateral recesses

The roof superior and inferior medullary velum and cerebellar

vermis

Apex tented into cerebellum

The upper part of the roof superior cerebellar peduncles and

the superior medullary velum (thin sheet of white matter)

The inferior part of the roof Inferior medullary velum (non-

nervous tissue) Medulloblastoma origin(Youman)

ROOF

FLOOR OF FOURTH VENTRICLE

Each inferolateral margin of the floor is marked by a narrow white ridge called taenia

The right and left taeniae meet at the inferior apex of the floor to form a small fold

called the obex

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

COMMUNICATION

It has a roof a floor and two lateral recesses

The roof superior and inferior medullary velum and cerebellar

vermis

Apex tented into cerebellum

The upper part of the roof superior cerebellar peduncles and

the superior medullary velum (thin sheet of white matter)

The inferior part of the roof Inferior medullary velum (non-

nervous tissue) Medulloblastoma origin(Youman)

ROOF

FLOOR OF FOURTH VENTRICLE

Each inferolateral margin of the floor is marked by a narrow white ridge called taenia

The right and left taeniae meet at the inferior apex of the floor to form a small fold

called the obex

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

It has a roof a floor and two lateral recesses

The roof superior and inferior medullary velum and cerebellar

vermis

Apex tented into cerebellum

The upper part of the roof superior cerebellar peduncles and

the superior medullary velum (thin sheet of white matter)

The inferior part of the roof Inferior medullary velum (non-

nervous tissue) Medulloblastoma origin(Youman)

ROOF

FLOOR OF FOURTH VENTRICLE

Each inferolateral margin of the floor is marked by a narrow white ridge called taenia

The right and left taeniae meet at the inferior apex of the floor to form a small fold

called the obex

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

The roof superior and inferior medullary velum and cerebellar

vermis

Apex tented into cerebellum

The upper part of the roof superior cerebellar peduncles and

the superior medullary velum (thin sheet of white matter)

The inferior part of the roof Inferior medullary velum (non-

nervous tissue) Medulloblastoma origin(Youman)

ROOF

FLOOR OF FOURTH VENTRICLE

Each inferolateral margin of the floor is marked by a narrow white ridge called taenia

The right and left taeniae meet at the inferior apex of the floor to form a small fold

called the obex

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

FLOOR OF FOURTH VENTRICLE

Each inferolateral margin of the floor is marked by a narrow white ridge called taenia

The right and left taeniae meet at the inferior apex of the floor to form a small fold

called the obex

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

The lateral recesses pouches below the cerebellar peduncles

Luschka CPA

The ventral wall of each lateral recess is formed by the junctional

part of the floor and the rhomboid lip

The rostral wall of each lateral recess Caudal margin of the

cerebellar peduncles

The peduncle of the flocculus which interconnects the inferior

medullary velum and the flocculus crosses in the dorsal margin of

the lateral recess

LATERAL RECESS

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

LATERAL RECESS

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

The caudal wall is formed by the tela choroidea which stretches

from the taenia and attaches to the edge of the peduncle of the

flocculus

The rootlets of the glossopharyngeal and vagus nerves arise ventral

and the facial nerve rostral to the choroid plexus which extends

through the lateral recess and the foramen of Luschka into the

CPA

The fibers of the vestibulocochlear nerve cross the floor of the

recess

LATERAL RECESS

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

LATERAL RECESS

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

The cavity or fossa of the fourth ventricle communicates with the

third ventricle superiorly as a continuation of the cerebral aqueduct

Inferiorly it extends as the central canal of the brainstem which in

turn runs through the vertebral column

The cavity also communicates with the subarachnoid space through

the three apertures

CAVITY

Foramina of the fourth ventricle

First described during the 19th century

Franc ois Magendie French physiologist Magendie (1783-1855)

Pioneer of experimental physiology

Hubert von Luschka German anatomist (1820-1875)

Rhoton provided detailed descriptions of the neurosurgical anatomy

of the fourth ventricle and its foramina

FORAMINA OF 4TH VENTRICLE

The choroid plexus of the fourth ventricle consists of several

segments

Its lateral segments extend laterally through the foramina of

Luschka (protruding into the cerebellopontine angle below the

flocculus and behind the glossopharyngeal vagus and accessory

nerves) and

Its medial segments extend longitudinally through the foramen of

Magendie

The tonsillar parts of the choroid plexus are located anterior to the

tonsils and extend inferiorly through the foramen of Magendie

CHOROID PLEXUS OF 4TH VENTRICLE

The PICA is intimately related to the inferior half of the roof

The PICA segment coursing in the cleft between the tonsil on one

side and the tela and velum on the opposite side is referred to as the

ldquotelovelotonsillar segmentrdquo3

This PICA loop which forms a convex rostral curve in its course

around the rostral pole of the tonsil is also referred to as either the

ldquocranialrdquo or ldquosupratonsillar looprdquo

VASCULAR RELATIONS

PICA

The main trunks of the anterior inferior cerebellar artery course near

the foramen of Luschka where they extend small choroidal

branches to the tela and choroid plexus in the lateral recess

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

First described during the 19th century

Franc ois Magendie French physiologist Magendie (1783-1855)

Pioneer of experimental physiology

Hubert von Luschka German anatomist (1820-1875)

Rhoton provided detailed descriptions of the neurosurgical anatomy

of the fourth ventricle and its foramina

FORAMINA OF 4TH VENTRICLE

The choroid plexus of the fourth ventricle consists of several

segments

Its lateral segments extend laterally through the foramina of

Luschka (protruding into the cerebellopontine angle below the

flocculus and behind the glossopharyngeal vagus and accessory

nerves) and

Its medial segments extend longitudinally through the foramen of

Magendie

The tonsillar parts of the choroid plexus are located anterior to the

tonsils and extend inferiorly through the foramen of Magendie

CHOROID PLEXUS OF 4TH VENTRICLE

The PICA is intimately related to the inferior half of the roof

The PICA segment coursing in the cleft between the tonsil on one

side and the tela and velum on the opposite side is referred to as the

ldquotelovelotonsillar segmentrdquo3

This PICA loop which forms a convex rostral curve in its course

around the rostral pole of the tonsil is also referred to as either the

ldquocranialrdquo or ldquosupratonsillar looprdquo

VASCULAR RELATIONS

PICA

The main trunks of the anterior inferior cerebellar artery course near

the foramen of Luschka where they extend small choroidal

branches to the tela and choroid plexus in the lateral recess

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The choroid plexus of the fourth ventricle consists of several

segments

Its lateral segments extend laterally through the foramina of

Luschka (protruding into the cerebellopontine angle below the

flocculus and behind the glossopharyngeal vagus and accessory

nerves) and

Its medial segments extend longitudinally through the foramen of

Magendie

The tonsillar parts of the choroid plexus are located anterior to the

tonsils and extend inferiorly through the foramen of Magendie

CHOROID PLEXUS OF 4TH VENTRICLE

The PICA is intimately related to the inferior half of the roof

The PICA segment coursing in the cleft between the tonsil on one

side and the tela and velum on the opposite side is referred to as the

ldquotelovelotonsillar segmentrdquo3

This PICA loop which forms a convex rostral curve in its course

around the rostral pole of the tonsil is also referred to as either the

ldquocranialrdquo or ldquosupratonsillar looprdquo

VASCULAR RELATIONS

PICA

The main trunks of the anterior inferior cerebellar artery course near

the foramen of Luschka where they extend small choroidal

branches to the tela and choroid plexus in the lateral recess

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The PICA is intimately related to the inferior half of the roof

The PICA segment coursing in the cleft between the tonsil on one

side and the tela and velum on the opposite side is referred to as the

ldquotelovelotonsillar segmentrdquo3

This PICA loop which forms a convex rostral curve in its course

around the rostral pole of the tonsil is also referred to as either the

ldquocranialrdquo or ldquosupratonsillar looprdquo

VASCULAR RELATIONS

PICA

The main trunks of the anterior inferior cerebellar artery course near

the foramen of Luschka where they extend small choroidal

branches to the tela and choroid plexus in the lateral recess

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

PICA

The main trunks of the anterior inferior cerebellar artery course near

the foramen of Luschka where they extend small choroidal

branches to the tela and choroid plexus in the lateral recess

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The main trunks of the anterior inferior cerebellar artery course near

the foramen of Luschka where they extend small choroidal

branches to the tela and choroid plexus in the lateral recess

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The largest vein of the

cerebellomedullary fissure

Originate nodule and uvula

courses laterally near the

junction of the inferior medullary

velum and tela choroidea

Courses dorsal or ventral to

the flocculus

CPA

Superior petrosal sinus

Venous system

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Ikezaki and co-workers classified posterior fossa ependymomas

into three groups based on location

(1)The lateral type presenting in the CPA characterized by a poor prognosis

secondary to involvement of cranial nerves and brainstem

(2) Ependymomas localized to the floor of the fourth ventricle with an

intermediate prognosis and

(3) Those localized to the roof of the fourth ventricle with the most favorable

outcome

Leptomeningeal dissemination

Medulloblastoma 33

Ependymoma 8 to 12

Spread and dissemination route

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Hydrocephalus is one of the conditions that can result from

blockage of the median and lateral apertures

In Arnold Chiari malformation (Type II Chiari malformation) the

medulla and the tonsils of the cerebellum come to lie in the

vertebral canal by descending through the foramen magnum

The median and lateral apertures are blocked by this condition

leading to obstruction of CSF flow

This causes internal hydrocephalus

Chiari II can also present with syringomyelia due to the

development of CSF-filled cyst or syrinx

CLINICAL IMPORTANCE OF 4TH

VENTRICLE

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

PICA

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Medulloblastoma is the most common malignant brain tumour in

children which arises in the cerebellum and can therefore impinge

on the roof of the fourth ventricle

The area postrema of the caudal region of the fourth ventricle is also

of clinical significance because of its role in the control

of vomiting

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

In adults the occlusion is rather acquired than congenital linked to

infection head trauma intraventricular haemorrhage tumours or

Arnold-Chiari malformation

Despite its rare occurrence congenital imperforation or

membranous obstruction of the foramen of Magendie must be

considered as a possible etiology of chronic hydrocephalus in adult

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Main pathological conditions affecting the

foramina of the fourth ventricle

1 Occlusion

(Infection head trauma intraventricular haemorrhage space-

occupying lesions congenital anomalies)

2 Membrane obstruction

3 Congenital imperforation (agenesis)

4 Idiopathic stenosis

5 Arachnoid adhesions

6 Cystic dilation

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Tumors of the ventricular system account for less than 1 of

intracranial lesions most of which are benign and slow growing

14 of all ventricular tumor occurs within the fourth ventricle

Tumor originating in 4th Ventricle

1 Medulloblastoma most common childhood

2 Ependyoma most common adults

3 Hemangioblastoma

4 Epidermoid cyst

Tumor expanding inside the 4th Ventricle

1 Astrocytoma

2 Oligodendroglioma

3 Exophytic cavernous malformation

Tumor of 4th venticle

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Medulloblastoma

Usually originates from inferior medullary velum from germinative cells

originating in the neuroepithelial roof of the fourth ventricle and grow anteriorly

into the fourth ventricle

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Hemangioblastoma

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

CHOROID PLEXUS PAPILLOMA

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

APPROACH

TO

4th VENTICULAR TUMOR

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

bull Midline pathology of the fourth ventricle that arises from the

cerebellar vermis or brainstem

bullTumors Medulloblastoma ependymoma-subependymoma as-

trocytoma choroid plexus papilloma hemangioblastoma dermoid-

epidermoid cysts brainstem glioma and metastatic lesions

bull Vascular lesions Arteriovenous and cavernous malformations

bull Inflammatory and infectious conditions Cerebellar and brainstem

abscesses

bull Traumatic or spontaneous hematomas

INDICATION

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

CSF diversion endoscopic ventriculostomy external ventricular

drain or permanent ventriculoperitoneal shunt

followed by microsurgical resection of the underlying ventricular tumor

Emergency Acute obstructive hydrocephalus or intratumoral

hemorrhage

INDICATIONS

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

In the past operative access to the fourth ventricle was obtained by

splitting the cerebellar vermis or by removing part of a cerebellar

hemisphere

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Dandy Median suboccipital craniectomy and splitting the vermis

TRANSVERMIAN APPROACH

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Transvermian approach provided slightly better visualization of the

medial part of the superior half of the fourth ventricular roof

(Disadv Lateral recess)

In cases where a tumor is located around the fastigium or originates

from the vermis

ADVANTAGES

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

It avoids complications related to injuries of the posterior inferior

cerebellar artery (PICA) branches to the brainstem and the inferior

and middle cerebellar peduncles

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

TELOVELAR(TRANSCEREBELLO-MEDULLARY FISSURE)

APPROACH

1980Rhoton AL Jr

This approach is identical to traditional midline approaches

Preserve the cerebellar tissue Anatomic plane through the tela choroidea and velum

interpositum

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Opening the CMF safe retraction of the cerebellar hemisphere

Good visualization of lateral recess

The cerebellar mutism syndrome Avoids vermian split

Early vascular control

ADVANTAGES OF TELOVELAR

APPROACH

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

STEPS OF TELOVELAR APPROACH

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

POSITIONING

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

INCISION

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The craniotomy includes opening of the foramen magnum dorsally

and is larger in the superior portion than in the inferior

CRANIOTOMY

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Dural opening is usually performed in a Y-shaped fashion

Bleeding from the occipital sinus can be controlled with silver dural clips or bipolar coaguation or running silk suture

DURAL OPENING

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

DECOMPRESSION OF CISTERNA

MAGNA

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Opening techniques for the telovelar approach depending on different

targets

Matsushima T et al

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Small arachnoid trabeculae around the tonsil is sharply cut and cerebellar tonsil is gently elevated off its inferior fixation

The superior portion of the tonsils is separated from the cerebellar vermis on both sides to gain access to the tela choroidea

Careful inspection of the tela reveals small branches of the PICA that supply the choroid plexus

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

In similar fashion the

caudal loop of the PICA

is freed from the

neuraxis by incising

small arachnoid

trabeculae while slightly

retracting the tonsils

laterally

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The uvula of the cerebellar

vermis is elevated gently with

a self-retaining retractor and

the arachnoid between the

uvula and the tonsil is

gradually incised to expose

the course of the PICA

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

The telovelar junction is

visualized

The superior medullary

velum may be further

divided to allow for more

rostral exposure of the

fourth ventricle

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

When the roof of the fourth

ventricle is adequately opened to

allow for exposure of the tumor

the interface of the tumor and

the brainstem is inspected

Cottonoid strip along floor and cervicomedullary junction

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Superior and lateral edges adherence to the cerebellum

Larger tumors debulk the tumor lateral margins

A point of origin of the tumor more adherant part

TUMOR INSPECTION

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Hemostasis cerebellum bipolar cautery or tamponade

Inspect aqueduct blood clot

Saline irrigation until clear

Finishing touch

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Closure

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Retraction injury to cerebellar tonsils vermis and cerebellar peduncles

Injury or occlusion of posterior inferior cerebellar arteries from

retraction

Injury to the floor of the fourth ventricle (brainstem)

Tracking of blood into third and lateral ventricles that may produce

hydrocephalus

Injury to the transverse sinus during the craniotomy

Significant blood loss or air emboli from occipital sinus or midline

occipital bone

Tumor dissemination along foramina and obex

AvoidancesHazards Risks

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

1 Postoperative hematoma

2 CSF leak

3 Infection

4 Cranial nerve deficits or other brainstem deficits

5 Hydrocephalus

6 Cerebellar deficits

7 Supratentorial epidural hematoma

8 Tumor residual or recurrence

9 Posterior inferior cerebellar artery or vertebral artery infarction

10 Cerebellar edema

Complications

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Medulloblastoma (13) ependymoma (10) and then choroid plexus

papilloma (2)

GTR8 cases (32) near total (˃80 of tumor volume) in 14 cases

(56) and subtotal excision (˂80 of tumor volume) in 3 cases

(12)

Cerebellar mutism in 2 cases (8) facial palsy 2 cases(8)

postoperative bulbar affection 3 cases (12)

Mortality 2

Conclusion Telovelar approach access Low incidence of CM

Retrospective study

25 cases with midline posterior fossa tumors

2012-2014

Neurosurgery Department Cairo University Egypt

Refaat MI Elrefaee EA Elhalaby WE (2016) Telovelar Approach for Midline Posterior Fossa Tumors in Paediatrics 25 Cases Experience J Neurol Disord 4315 doi 1041722329-68951000315

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References

Thank you

1 Mussi AC Rhoton AL Telovelar approach to the fourth

ventricle microsurgical anatomy JNS 200092(5)812-23

2 Schmidek and Sweet operative technique 6th Edn

3 Refaat MI Elrefaee EA Elhalaby WETelovelar Approach

for Midline Posterior Fossa Tumors in Paediatrics 25 Cases

Experience J Neurol Disord 20164315

References