Post on 16-Jul-2015
Anterior cranial fossa 360°29-9-20167.49 pm
Great teachers – All this is their work . I am just the reader of their books .
Prof. Paolo castelnuovo
Prof. Aldo Stamm Prof. Mario Sanna
Prof. Magnan
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Anterior & Posterior perforated substance
Anterior perforated substance & olfactory track relation
Trasnasal endoscopic view FPA = Fronto-polar artery ; FOA = Fronto-orbital artery
Recurrent artery of HUEBNER
Recurrent Rathke's Cleft cyst,previously operated in Russia by external approach.Case done with Dr.V.S.Mehta sir...Showing the beautiful anatomy of suprasellar area. Note the loss of right optic nerve fibers due to compression
of the cyst.
Trascranial view FPA = Fronto-polar artery ; FOA = Fronto-orbital artery
FPA = Fronto-polar artery ; FOA = Fronto-orbital artery
Transnasal endoscopic view Trascranial view
Bifrontal craniotomy view FPA = Fronto-polar artery ; FOA = Fronto-orbital artery
The carotid bends laterally in the nasopharynx before entering the petrous temporal bone. It then swings anteriorly before becoming the paraclival carotid in the floor of the sphenoid and
progresses vertically into the cavernous sinus and then enters the anterior cranial fossa giving off the middle cerebral artery (MCA) to become the anterior cerebral artery.
Dry bone specimen following a frontal drillout procedure. This specimen clearly shows the close relationship between the frontal sinuses and the cribriform plate, and hence the advantage of the
drillout procedure for anteriorly based lesions. AT of FS, anterior table of frontal sinus; PT of FS, posterior table of frontal sinus; FC, foramen cecum; CP, cribriform plate; CG, crista galli.
Always one cell [ AEC ] present anterior to AEA . Cadaveric dissection image of the left ethmoid cavity revealing the anterior ethmoidal
artery (AEA) located one anterior ethmoidal cell (AEC) posterior to the frontal sinus (FS). OF, orbital fat; PO, periorbita.
.• When approaching an olfactory groove
meningioma, regardless of approach, both theextra- and intradural arteries associated with the tumor must be controlled. The anterior and posterior ethmoidal arteries provide the major extradural blood supply to the tumor
Anterior ethmoidal artery has to be cauterized on cerebral side , if you do on orbital side it may retract & cause retro-orbital haemorrhage
Cadaveric dissection image demonstrating the left anterior ethmoidal artery (AEA) and nerve (AEN) running across the skull base toward the middle turbinate (MT) attachment. Here it can be seen dividing into several
branches including the anterior falcine artery (AFA) to supply the falx cerebri. LP,
lamina papyracea. - In Olfactory meningioma surgery the small, falcine arterioles that feed the tumor can be coagulated. Sacrificing these arteries early in the dissection provides further tumor
devascularization.
Cadaveric dissection illustrating the anatomy of the anterior skull base following partial resection of both middle turbinates (MT) and nasal septum. The communal
frontal sinus (FS) ostium can be seen anteriorly with both fovea ethmoidalis (FE) exposed. The lateral margins are the lamina papyracea (LP) and posteriorly the
planum sphenoidale (PS) can be seen. OF, olfactory fossa; AEA, anterior ethmoidalartery; PEA, posterior ethmoidal artery; AEN, anterior ethmoidal nerve; PEN, posterior
ethmoidal nerve.
Cadaveric dissection with osteotomies created using a diamond drill.
The anterior attachment of the falx cerebri (FC) to crista galli (CG) is seen. Note the superior sagittal sinus (SSS) running in the superior aspect of the falx cerebri within the inferior sagittal
sinus (ISS) in the lower margin of the falx cerebri. The inferior sagittal sinus becomes the straight sinus (SS) after it joins with the great cerebral vein.
Cadaveric dissection demonstrating the skull base scissor cutting the attachment of the falx cerebri (FC) to
the crista galli.
The skull base is placed under traction and the remaining posterior falxcerebri still holds the skull base. This needs to be cutbefore the skull base can be dropped into the nose.
I THINK AFTER SEPERATION OF FRONTAL LOBES WE SEE ANTERIOR CEREBRAL ARTERIES - REFER
Cadaveric dissection image: the skull base has been removed affording a view of the inferior aspect of both anterior cerebral lobes. The olfactory bulbs (OB), branches of the anterior cerebral
artery (ACa), and cut inferior aspect of the falx cerebri (FC) can be seen. FS, frontal sinus; AEA, anterior ethmoidal artery; LP, lamina papyracea. -
Fronto-polar artery
ACA anterior cerebral artery, APAs anterior perforating arteries, FOA fronto-orbital artery,FOV fronto-orbital vein, FPA fronto-polar artery, ICAi intracranial segment of the internal
carotid artery, MCA middle cerebral artery, OlfT olfactory tract, OlfV olfactory vein, ON opticnerve, PS pituitary stalk, TL temporal lobe, black asterisk anterior communicating artery
Dear surgeons cadeveric craniectomy see frontal lobes gyrus recti falxfronto polar arteries draff type3 all in one – Dr. Sree Ram Murthy
F = Frontal , LP = Lamina papyrecea , GR = Gyrus rectus
Two-suction technique for tumor resection. Note that the righthanded suction is providing traction while the other suction is dissecting soft tumor.
Microneurosurgical techniques for tumor removal include the internal debulking of the tumors, followed by the mobilization of the tumor capsule to allow early identification and extracapsular
dissection of neurovascular structures, and the coagulation and removal of the remaining capsule. This sequence is repeated multiple times until final sharp dissection of the residual capsule is completed. These time-proven techniques are designed to minimize the risk of injury to important structures and are critical elements for the removal of any tumor with any surgical approach. Endoneurosurgicaltumor removal adheres to the same dissection principles of open approaches and avoids blind dissection of tumors from vessels and nerves. Under no circumstances are tumors extracted by pulling without seeing the underlying structures. If the technique above cannot be performed the resection
must be abandoned.
Prof . Amin kassam
statements
Suprasellar/transplanumapproach:Drill the bone of the planum sphenoidale until paper-thin.It is important to recognize that the planum has arhomboid geometry, bound by the optic nerve canals laterally and the tuberculum sella strut posteriorly.The bone of the planum is removed in an anterior toposterior direction displacing it inferiorly to gain distal access.The dura is very adherent over this area. Removalof the bone using rongeurs in a posterior to anterior direction universally results in a duralinjury (before intradural control of the anatomy).The tuberculum strut needs to be drilled until very thin; then, it can be fractured and removed. This will expose the superior intercavernous sinus that can be then be coagulated and/or clipped and divided & surgiflo applied if it is still bleeding . Open the dura and identify the optic nerves, (RON & LON) chiasm and tracts, the infundibulum, and ICAs.
Anterior and posterior ethmoid arteries control:
Identify the anterior (AEA) and posterior ethmoidarteries(PEA) inside the orbital cavity, displacing the periorbitalaterally to assist with their visualization.
Note the orientation of the arteries.
Uncap their bony canal, dissect the neurovascular bundleout of the canal and transect them.
Frontal sinusotomy (Draf III):Enlarge the nasofrontal recess anteriorly and medially (drill or rongeurs) to reach the nasal septum (Draf IIb).Extend the resection of the posterior nasal septum toreach the level of the anterior wall of the frontal sinus.
At this point you should be able to see both nasofrontal recesses from either side of the nose.
Remove the floor of the frontal sinuses across the midlinewhile remaining anterior to the posterior wall of thefrontal sinus and the crista galli. Remove the “frontalbeak” and extend the resection of the floor anteriorly untilyou can visualize the anterior wall of the frontal sinus.
Anterior craniofacial resection (Trans-cribiform Approach):Resect any remnants of the superior attachments of the posterior nasal septum, middle and superior turbinates. Complete a “sequential layered resection” removing the mucoperiosteum and olfactory filaments; then, the bone of the fovea ethmoidalis and cribiform plate; and then, the dura:
a) remove the mucosa with through-cutting instruments.
b) drill the fovea ethmoidalis medial to its junction with the roof of the orbit and the cribiform plate until they are paper-thin and remove with blunt instruments
c) drill out crista galli.
Incise the dura along the lateral edge of the bony defect and join the longitudinal incisions anteriorly with a horizontal incision. Extend the latter medially to reach the falx cerebri bilaterally.
The falx cerebri can be transected in an anterior to posterior fashion, only after the identification of the anterior fossa
vasculature ( frontopolar and fronto-orbital vessels).
Sharp dissection [ key principle in transcibriform approach ] is utilized to allow
for extracapsular dissection. Note, that the suction provides retraction of the tumor (T) and tension along the band. The fronto-polar artery (FPa) is preserved
along the frontal lobe (F) while an olfactory groove meningioma (T) is being removed.
A blunt dissector is being utilized to establish a dissection planebetween a left olfactory bulb (OB) invaded by cancer and the gyrus
rectus (GR).
What is Danny’s ligament
Recurrent artery of heubner originates near Acom
(A) The middle cerebral artery (MCA) gives rise to the lateral lenticulostriate arteries (LLA) at the bifurcation complex. The medial lenticulostriate arteries (MLA) arise from the proximal section of A1. At the juncture of A1-AComm-A2 the recurrent artery of Heubner (RAH) is given off. AComm completes the anterior portion of the circle of
Willis and has several perforating vessels ( Acomm Perf) that head posteriorly. In the first 5 mm of A2 the orbitofrontal ( OF) artery is given off with the frontopolar (FP)
artery staying more medial. (B) A clinical picture after removal of a tuberculum sellameningioma with a well-defined display of the anterior cerebral arteries.
In the lateral border of the chiasmatic cistern the first part ofthe ICAi is visible.
Dry bone dissection image taken with a 30-degree endoscope demonstrating the fovea ethmoidalis (FE) and cribriform plate (CP) junction with the planum sphenoidale (PS). This is marked approximately by the posterior ethmoidale artery (PEA). ISS, intersinus septum of sphenoid sinus; ON, optic nerve; CCA, anterior genu of the intracavernous carotid artery.
Preoperative CT angiogram showing the close association of the tumor capsule of an olfactory groove meningioma with the anterior
cerebral arteries (arrows). – sometimes ACA present in the posteior part of the tumor
In contrast, craniopharyngiomas within the pre-chiasmatic space can be removed via a supraorbital or endonasal route, while tumors with lateral extensions or
supra-chiasmatic extensions can be most effectively removed by a supra-orbitalor lateral transcranial approach. – from craniopharyngioma book
When the ACAs present in the posterior part of the tumor BIFRONTAL approach is used – by Dr.Lee
• Add video clipping
MRI scans show the A1 (solid white arrow) leaving the middle cerebral artery juncture toward the AComm (dashed white arrow) with the A2s (black arrow) progressing superiorly. These vessels are all within the substance of the tumor.
The clinical dissection of this tumor is seen in (C) and (D) with tumor encompassing the perforators (Perf) coming off the AComm. Once all tumor had been removed the vascular complex with A1-AComm,-A2 and the important branch
of A1, the recurrent artery of Heubner ( RAH), and the A2 branch, orbitofrontal (OF) artery, are clearly visible.
The lateral limit of resection for olfactory groove meningiomas is the midorbitalvertical meridian (fig. 5). This limitation is created by, as we believe most limitations
are, a nerve, in this case the optic nerve. Removal of the lamina papyracea allowsgentle retraction of the periorbita and orbital contents to allow access to the orbital
roof out to the midorbit.
Coronal post-contrast T1-weighted MRI showing the lateral limit of resection at the midorbitalvertical meridian (dotted line). b Postoperative post-contrast T1-weighted MRI showing complete
resection out to midorbit via EEA.
Endoscopic endonasal view of the anterior
skull base following the sinonasalportion
of the approach. Dashed lines represent the
osteotomies to be performed for dural access.
Endoscopic endonasal view of the right
posterior ethmoidal artery for bipolar coagulation
and ligation.
• There are often multiple fine falcine arterioles that provide additional blood supply to olfactory groove meningiomas. Following tumor debulkingon either side of the falx, these arterioles can be carefully transected and coagulated during the resection of the falx to provide further tumor devascularization.
• The tumor should not be detached anteriorly before all of the internal debulking is complete, as frontal lobe descent can obscure visualization.
In coronal MRI scans (A,B) and parasagittal MRI (C) the two consistencies of tumor are visible. The soft tumor is marked with a solid white arrow whereas the calcified tumor is marked with a broken white arrow. In coronal CT scan (D) the calcified part of the tumor is clearly seen (white
broken arrow). (A,B) Brain edema is indicated with a solid black arrow. The other importantfeature seen in (C) is the close approximation of the tumor to the posterior wall of the frontal
sinus (broken black arrow). This means that the anterior osteotomy should be through the posterior wall of the frontal sinus.
video of olfactory groove Schwannoma
https://www.youtube.com/watch?v=NLtOGfKWC6U
Olfactory groove meningioma – endoscopic approah
https://www.youtube.com/watch?v=J9s9LH9bkb8
Olfactory groove meningioma – microsocpicapproah
https://www.youtube.com/watch?v=UtwECuh4kUg&spfreload=10
Transcribriform tumor excision -by Dr.Satish Jain
https://www.youtube.com/watch?v=ZRNSAc8B3So
Interhemispheric approach & transcallossal for craniopharyngioma
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“ Skull base 360° ”I will update continuosly with date tag at the end as I am
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