PTERYGOPALATINE FOSSA & ITS APPROACHES

DR.ASHWIN MENON

PTERYGOPALATINE FOSSA

• A small space between the posterior surface of the Maxilla and the Pterygoid process of the Sphenoid bone.

BOUNDARIES• It can be considered as a pyramidal space:

• ANTERIOR: posterior surface of maxilla below floor of orbit• POSTERIOR: lateral pterygoid plate and a part of medial plate

also• MEDIAL: perpendicular plate of palate

• LATERAL: pterygomaxillary fissure

• SUPERIOR: under surface of greater wing of sphenoid

• INFERIOR: ABSENT (the post wall meets the ant wall and between them is greater palatine canal)

ANTERIOR WALL

POST WALL OF MAXILLA

INFERIOR ORBITAL FISSURE

ORBIT TRANSMITS INFRAORB VESSELS,NERVES, ASC BR OF PtP GANG

POSTERIOR WALL

LATERAL AND MEDIAL PTERYGOID PLATES

PTERYGOID CANAL MIDDLE CRANIAL FOSSA NEAR F.LACERUM

TRANS VIDIAN NERVE AND VESSELS

MEDIAL WALL

PERP PLATE OF PALATE

SPHENOPALATINE FORAMEN

NASAL CAVITY SP ARTERY BR AND PtP GANG BRANCHES TO NP MUCOSA

LATERAL WALL

GAP BETWEEN THE PTERYGOID PLATES AND MAXILLA

PTERYGOMAXILLARY FISSURE

INFRATEMPORAL FOSSA

TRANS MAX ARTERY

SUPERIOR WALL

GREATER WING OF SPHENOID

F. ROTUNDUM MID CRANIAL FOSSA

TRANSMITS MAXILLARY NERVE

INFERIORLY ABSENT GREATER PALATINE AND LESSER PALATINE CANALS

ORAL CAVITY ROOF

GREATER PALATINE AND LESSER PALATINE NERVES AND VESSELS

CONTENTS

MAXILLARY NERVE

3RD PART OF MAXILLARY ARTERY

PTERYGOPALATINE GANGLION

NERVE OF PTERYGOID CANAL

Fat (Bichat’s)

TRIGEMINAL NERVE

BRANCHES

BRANCHES

MAXILLARY NERVE

•ORIGIN- From a semilunar ganglion in Meckel’s cave as 2nd part of trigeminal nerve.•Sensory nerve.

IN MID CRANIAL FOSSA

MENINGEAL BRANCH DURA

IN PTERYGOPALATINE FOSSA

ZYGOMATIC BRANCH ENTERS ORBIT THROUGH INFRA ORBITAL FISSURE, THROUGH ZYGOMATICO ORBITAL FORAMEN AND SUPPLIES LACRIMAL GLAND AND ZYG-FACIAL AND ZYG-TEMP

GANGLIONIC BRANCH PTERYGOPALATINE NERVES TO GANGLION

POSTERIOR SUPERIOR ALVEOLAR NERVE

ENERS POST SURFACE OF MAXILLA AND SUPPLY MOLARS

IN ORBIT ANT SUP ALV NERVE(FROM INFRAORBITAL NERVE- A CONTINUATION OF MAXILLARY)

MAIN TRUNK AFTER ENTERING ORBIT, GIVES THIS BRANCH FOR PREMOLARS, CANINE AND INCISORS

MIDDLE SUPERIOR ALV NERVE SEEN AT TIMES

IN FACE TERMINAL BRANCHES PALPABRAL, NASAL, LABIAL, LOWER EYELID, ANT NASAL APERTURE, ANT CHEEK

PTERYGOPALATINE GANGLION

• The pterygopalatine ganglion (ganglion pterygopalatinum, meckel's ganglion, nasal ganglion, sphenopalatine ganglion) is a parasympathetic ganglion found in the pterygopalatine fossa.

• It is one of four parasympathetic ganglia of the head and neck. (The others are submandibular gang., otic gang., and ciliary gang.).

PTERYGO PALATINE GANGLION (HAY FEVER GANGLION)

PARASYMPATHETIC (SECRETOMOTOR)

SUPERIOR SALIVATORY AND LACRIMAL NUCLEAS (PONS) – FACIAL NERVE – IN MID EAR TRVELS THROUGH GREATER SUPERFICIAL PETROSAL NERVE – THROUGH A HIATUS ENTERS MID CRANIAL FOSSA – ENTERS F. LACERUM – JOINS WITH DEEP PETROSAL NERVE (SYMPATHETIC) – VIDIAN NERVE – PTERYGOID CANAL – PTERYGOPALATINE FOSSA, RELAYED BY PPt GANG – POST GANG FIBRES SUPPLY LACRIMAL, NASAL, PALATINE GLANDS

SYMPATHETIC (VASOCONSTRICTOr)

FROM T1 AND T2 SEGMENTS OF SPINAL CORD – SUPERIOR CERVICAL SYMPATHETIC GANGLION – PLEXUS AROUND INTERNAL CAROTID –DEEP PETROSAL NERVE AT THE LEVEL OF F.LACERUM – PASSES THROUGH THE GANG WITHOUT RELAYING – SUPPLIES THE SAME GLANDS

SENSORY FROM GANGLIONIC BRANCHES OF MAXILLARY NERVE

BRANCHES

ASCENDING DESCENDING POSTERIOR MEDIAL

ORBITAL BRANCHES (secreato motor to lacrimal and ethmoidal air cells)

GREATER PALATINE NERVE (supplies hard palate and gives off Postero inferior lateral nasal branches)

PHARYNGEAL BRANCH (supplies pharyngeal mucosa around the eust. tube orifice)

POSTERIO- SUPERIOR MEDIAL NASAL (antero-inf septum and floor of nose)

LESSER PALATINE NERVE (supply soft palate and tonsils)

NASOPALATINE NERVES (roof of the mouth)

POSTERO-SUPERIOR LATERAL NASAL (upper lateral quadrant of nasal septum)

NERVE OF PTERYGOID CANAL(VIDIAN NERVE)

• The nerve of the pterygoid canal (Vidian nerve) is formed by the junction of the great petrosal nerve and the deep petrosal nerve within the pterygoid canal containing the cartilaginous substance which fills the foramen lacerum.

• It passes forward through the pterygoid canal with its corresponding artery (artery of the pterygoid canal) and is joined by a small ascending sphenoidal branch from the otic ganglion. It then enters the pterygopalatine fossa and joins the posterior angle of the pterygopalatine ganglion.

• Parasympathetic preganglionic fibers from the facial nerve (contained within the greater petrosal nerve) which synapse in pterygopalatine ganglion.

• Sympathetic postganglionic fibers from the deep petrosal nerve which do not synapse in pterygopalatine ganglion.

• The postganglionic parasympathetic fibers of the deep petrosal nerve, upon synapsing in the pterygopalatine ganglion, will distribute to the nose, palate, and lacrimal gland through various nerves leaving the pterygopalatine fossa.

VIDIAN CANAL• It is through this canal the vidian nerve passes. This is a

short bony tunnel seen close to the floor of sphenoid sinus. This canal transmits the vidian nerve and vidian vessels from the foramen lacerum to the pterygopalatine fossa.

• According to CT scan findings the vidian canal is classified into:

Type I: The vidian canal lies completely within the floor of sphenoid sinus

Type II: In this type the vidian canal partially protrudes into the floor of sphenoid sinus

Type III: Here the vidian canal is competely embedded in the body of sphenoid bone

ARTERY OF THE PTERYGOID CANAL

• The artery of the pterygoid canal (Vidian artery) is an artery that can arise from the internal carotid (ICA) or external carotid (ECA), or serve as an anastomosis between these arteries.

• It more commonly arises from the ECA.

• The artery passes backward along the pterygoid canal with the corresponding nerve. It is distributed to the upper part of the pharynx and to the auditory tube, sending into the tympanic cavity a small branch which anastomoses with the other tympanic arteries.

MAXILLARY ARTERY

• The main arterial supply to the infratemporal fossa

• Largest terminal branch of the external carotid artery

• The maxillary artery arises just posterior to the neck of the mandible in the substance of the parotid gland and courses somewhat obliquely through the fossa to end in the pterygomaxillary fissure.

• Through its course It usually lies lateral (superficially to the lateral pterygoid muscle, but it can sometimes lie on the deep side of the muscle.

• Divided into three parts by lateral pterygoid muscle

• BRANCHES:-

1ST PART 2ND PART 3RD PART

IN FRONT OF STYLOMAND LIGAMENT ALONG THE LOWER BORDER OF LAT PTERYGOID

DEEP TO LATERAL PTERY MUSCLE UPTO PTERYGOMAXILLARY FISSURE

ENTERS PTERYGOMAXILLAY FISSURE INTO PTERYGOPALATINE FOSSA

1ST PART 2ND PART 3RD PART

Deep auricular Anterior tympanicMiddle meningealAccessory meningealInferior alveolar

Deep temporal MassetericPterygoidBuccal

Post . Superior alveolarInfra orbitalGreater palatineSphenopalatinePharyngeal Art.of pterygoid

canal

THIRD PART OF MAXILLARY ARTERY• Enters pterygopalatine fossa through

Pterygomaxillary fissure.GREATER PALATINE AND LESSER PALATINE ARTERIES

THROUGH THE GP AND LP CANALS AND SUPPLIES HARD AND SOFT PALATE

POSTERIOR SUPERIOR ALVEOLAR ARTERY

MOLARS, PREMOLARS AND MAXILLARY SINUS

SPHENOPALATINE ARTERY ENTERS NOSE THROUGH POSTERIOR PART OF SUPERIOR MEATUS, THROUGH SPHENOPALATINE FORAMENDIVIDES INTO: POST LATERAL NASAL AND POST SEPTAL

ARTERY OF PTERYGOID CANAL SUPPLIES THE ROOF OF THE PHARYNXPHARYNGEAL ARTERY SUPPLIES ROOF OF NASOPHARYNXINFRA ORBITAL ARTERY CONTINUATION OF THE MAX ARTERY, ENTERS ORBIT

AND APPEARS IN FACE THROUGH INFRA ORBITAL FORAMEN

ANTERIOR SUPERIOR ALVEOLAR (INFRA-ORBITAL BR)

BEFORE EXITING THROUGH THE INFRA-ORBITAL FORAMEN

IMAGING

IMAGING

Contrast-enhanced axial CT scan shows pterygopalatine fossa (arrows) between posterior wall of maxillary sinus and anterior surface of pterygoid process of sphenoid bone. Fossa is seen as low density because of contained fat.

CLINICAL SIGNIFICANCE

• REFERRED OTALGIA:Mandibular nerve also innervates a portion of ear (by Auriculo-Temporal branch) and hence pain in infected lower tooth (by Inferior alveolar branch) may be referred to ear

• FORAMEN OVALE LESION:Paraesthesia of mandible, teeth and side of the face and paralysis of Masticatory muscles, hearing abberations and jaw jerk loss

• HAY FEVER GANGLION: In allergic states, congestion of the nasal glands, lacrimal glands and palatine glands result in running nose and lacrimation due to stimulation of Pterygopalatine ganglion. Hence it is called “Hay fever ganglion”

NERVE BLOCKS

• INFERIOR ALVEOLAR NERVE

• MAXILLARY NERVE

• MANDIBULAR NERVE

INFERIOR ALVEOLAR NERVE BLOCK

• By inserting the needle, lateral to pterygomandibular raphae, about 6-10mm above the occlusal table of mandibular teeth, then sliding posteriorly along the medial aspect of the ramus.

• Approach area of injection from contralateral premolar region ,with other hand thumb retracting the buccal mucosa pressing on the coronoid process.

• Vicinity of mandibular foramen can be reached.• Tongue and skin of chin are also anaesthetised due to

Lingual and mental nerve blockade.

MAXILLARY NERVE BLOCK

• By inserting the needle, through the mandibular notch (gingivo buccal sulcus opp to 2nd molar) and guiding it 45degrees superiorly and medially, along the pterygoid plate, until the pterygopalatine fossa is reached at a depth of 6-7 cm .

• This can be confirmed by absence of bony resistence and adjusting the angle accordingly.

• Foramen rotundum can be reached.• Useful in trigeminal neuralgia involving maxillary

division.

MANDIBULAR NERVE BLOCK

• By inserting the needle – 4cm deep through Mandibular notch and sliding the needle posteriorly along the lateral surface of the pterygoid plates.

• Foramen ovale can be reached.

• Useful in trigeminal neuralgia involving Mandibular division.

JUVENILE NASOPHARYNGEAL ANGIOFIBROMA

• Spread of a tumor along the axis of Pterygomaxillary fissure with the expansion of the walls.

• Tumor in the sphenopalatine foramen can spread to pterygopalatine fossa and through the PtM fissure into the infratemporal fossa.

• Most important sign in the imaging is the ‘bowing’ of posterior wall of Antrum.

• They quickly spread to parapharyngeal and carotid space.

APPROACHES TO PTERYGOPALATINE FOSSA

• TRANS ANTRAL APPROACH

• TRANS NASAL APPROACH

• TRANS PALATAL APPROACH

TRANS ANTRAL APPROACH

• Golding Wood -1961(Classic)• Vidian neurectomy• Maxillary artery ligation

• Nomura -1974 (sub periosteal)

VIDIAN NEURECTOMY

Indications:-• Severe intractable vasomotor rhinitis• Crocodile tears• Senile nasal drip• Severe recurrent nasal polyposisGeneral anaesthesia-hypotensive-60 mm/HgAntrum opened (wider) as for Caldwell Luc procedure- preserve infra orbital nerve

• Elliptical Posterior antral window is made with chisel cuts after removing mucosa

• A Zeiss microscope with 300 mm lens used to remove only bone

• Exposing maxillary artery, cleaning and application of occluding clips and division.

• Artery is displaced

downwards seek for

maxillary nerve and trace upto

foramen rotundum.

• Identify and follow spenopalatine bundle medial to maxillary nerve and trace it upto medial butress.

Identify and follow

spenopalatine bundle medial to maxillary nerve and trace it upto medial butress

where shenopalatine

artery lies anteriorly.

• Shenopalatine bundle traced further medially to find the ganglion where it diverges to descending palatine and nasal branches.

• Shenopalatine ganglion is found 8mm medial and inferior to foramen rotundum.

• A hook is slipped over divergence of Shenopalatine bundle and sickle knife passed beneath it to cut VIDIAN NERVE emerging from pterygoid canal.

The mouth of canal is then

coagulated with diathermy.

• Surgery is completed with haemostasis

Post op complications

1. Absence of lacrimation2. Facial analgesia3. Ophthalmoplegia4. Infection of antrum

Maxillary artery ligation

• Indications:-1. Acute massive epistaxis2. Recurrent massive epistaxis3. Herditary telengectiasis4. Nasopharyngeal angiofibroma

TRANS NASAL APPROACH

• Endoscopic • Minnis and Morrison -1971(Trans septal)• Patel and Gaikward -1975 (Direct)

Endoscopic Transsphenoidal Approach

• After general anesthesia is administered, the patient is placed in the semi-Fowler position.

• Cottonoids soaked with diluted epinephrine (1:100 000) and cocaine, 10% benzoylmethylecgonine),are positioned between the middle turbinate and the nasal septum to enlarge the space between them and to obtain decongestion of the nasal mucosa.

• The head of the middle turbinate is delicately dislocated laterally to further widen the virtual space between the middle turbinate and the nasal septum.

• After creation of adequate space between the middle turbinate and the nasal septum, the endoscope is angled upward along the roof of the choana until it reaches the sphenoid ostium, usually located approximately 1.5 cm above the roof of the choana.

• Once the sphenoid cavity is reached, coagulation of the area around the sphenoid ostium is performed. This serves to avoid arterial bleeding originating from septal branches of the sphenopalatine artery.

• Ostium enlargement proceeds circumferentially by use of bone punches; care must be taken in the inferolateral direction, where the sphenopalatine artery or its major branches lie.

• Once the anterior sphenoidotomy is completed, A 70° endoscope is used to identify the vidian canal, usually at the sphenoid sinus floor, lateral to the natural ostium. Transection of the nerve is performed using an angle probe under direct vision.

Intraoperative endoscopic views of the transsphenoidal approach. The vidian canal can be visualized at the floor of the sphenoid sinus. A probe is used to transect the vidian canal.Successful transection of the vidiannerve is performed by direct vision.

• The fragment of the nerve is removed whenever possible and is sent for pathologic examination. At the end of the procedure, hemostasis is obtained, and the middle turbinate is gently restored in a medial direction.

• Packing of the nasal cavity- bleeding from the nasal mucosa- usually removed on the second day. Most patients are discharged 2 days after surgery.

TRANSNASAL APPROACH

• The patient is prepared, and the sphenoid ostium is identified as in the transsphenoidal approach. Sphenoidotomy is performed near the level of the sphenoid sinus floor.

• Just enough space is offered for the entrance of a 4-mm endoscope. The mucoperiosteum is elevated off the anterior and inferior surfaces of the sphenoid

• The vidian canal can usually be identified between its exit from the sphenoid bone and its entrance into the pterygopalatinefossa, usually medial to the root of the middle turbinate.

• The nerve is subsequently transected by a sickle knife or by an angle probe. The remainder of the procedure is performed as described for the transsphenoidal approach.

TRANS PALATAL APPROACH• Done under GA• Boyle – Davis mouth gag• Curving incision 1 cm anterior to the posterior

margin of hard palate• 5mm bone removed• 300mm Zeiss microscope –visualise ET orifice• Incision over mucosa to expose medial

pterygoid plate, -which is removed with burr• Pterygoid canal is 2-3 mm deep- cauterised

Maxillary nerve block

• Maxillary nerve may be blocked in PPF by anaesthetic infiltration to greater palatine canal

• Also a method of anaesthesia to posterior superior alveolar nerve

• Indications:1. Dento facial deformities2. Maxillary sinus surgeries3. Diagnostic or therapeutic in trigeminal

neuralgia cases

• Two intra oral approaches

i. High tuberosity approach and ii. Greater palatine canal approach

High tuberosity approach- direct needle posteriorly superior and medially along zygomatic and infraorbital surfaces of maxilla to enter the PPF

• Depth of insertion is measuring distance from gingival crest of premolar to infra orbital rim on face

Greater palatine canal approach-7mm anterior to jn. Of hard and soft palate- a 25 g needle bent at 45 degree parallel to mid sagittal plane-in postero superior direction-gently rotate the needle as it falls into the canal

THANK YOU!!!