11 Preauricular Transzygomatic Approach to the Anterior Infratemporal Fossa and Middle Infratemporal Fossa
10.1055/b-0034-63759
11 Preauricular Transzygomatic Approach to the Anterior Infratemporal Fossa and Middle Infratemporal Fossa
The preauricular transzygomatic anterior infratemporal fossa approach affords the surgeon access to the infratemporal and pterygoid fossae through the middle fossa. This is particularly useful for treating tumors involving the bones at the base of the middle fossa, such as trigeminal schwannomas with an extracranial component, maxillary tumors, nasopharyngeal carcinomas, meningiomas with infratemporal invasion, juvenile nasopharyngeal angiofibromas, and chondroblastomas.
The preauricular transzygomatic middle infratemporal fossa approach affords the surgeon access to the retropharyngeal space, middle and lower clivus, and anterior arch of the atlas. The main corridor of this approach is between V 3 and the styloid process. This approach provides access to the lesions of clivus and the infratemporal internal carotid artery from a superiolateral approach. A condylectomy can result in postoperative ankylosis, and should be avoided if possible.
Step 9. Unroofing the mandibular and maxillary branches of the trigeminal nerve (Fig. 11.34)
Step 10. Removing the pterygoid process (Fig. 11.52)
Step 11. Identifying the eustachian tube (Fig. 11.70)
Illustrated Steps with Commentary
Fig. 11.1 (Step 1) Skin incision.A sickle shaped incision is made beginning 5 mm below the inferior border of the root of the zygomatic arch. A. This incision, the less invasive approach, is in most cases adequate to access the infratemporal fossa and adjacent regions. It preserves the pterygoid muscles. B. This incision, the extended approach, allows the skin flap to be retracted more anteriorly for removal of the lateral and medial pterygoid muscles to access the parapharyngeal region and the nasopharynx. This approach also allows the infratemporal approach to be combined with a transorbital or transcavernous approach. The wider approach allows the trajectory of the surgeon’s vision to pass more inferiorly. (Zy, zygoma)Fig. 11.2 Temporoparietal muscle and fascia.The skin, temporoparietal muscle, temporoparietal fascia, and galea are incised, preserving the deep temporal fascia. (sDTF, superficial layer of the deep temporal fascia; TPM, temporoparietal muscle)Fig. 11.3 Auricularis anterior muscle and fascia.Cutting through the temporoparietal fascial over the ear, the surgeon will note a thin muscle that takes origin from the fascia and inserts in front of the helix. This is the auricularis anterior muscle, more commonly called the anterior portion of the temporoparietal muscle. The temporoparietal fascia is separated from the superficial layer of the deep temporal fascia. (LAT, loose areolar tissue; sDTF, superficial layer of the deep temporal fascia; TPM, temporoparietal muscle)Fig. 11.4 Deep temporal (interfascial) fat pad.The deep temporal fat pad is seen splitting the temporalis fascia into a deep and a superficial layer. The yellow fat pad can be seen under the superficial layer of the temporal fascia. The superficial layer is contiguous with the superficial periosteum of the zygoma. The superficial layer of the temporalis fascia can be separated by raising the periosteum from the origin of the zygomatic process of the frontal or temporal bones. Following this plane over the muscle will separate the superficial from the deep layer of the fascia. (sDTF, superficial layer of the deep temporal fascia)Fig. 11.5 An incision is made in the superficial layer of deep temporal fascia to expose the deep temporal fat pad.The superficial layer of the temporal fascia is separated from the deep layer and the superficial layer is raised along with the scalp ap to protect the frontal branch of the facial nerve. (dDTF, deep layer of the deep temporal fascia; IFF, interfascial fat pad; sDTF, superficial layer of the deep temporal fascia)Fig. 11.6 (Step 2) Raising skin ap.The skin ap is raised with the superficial layer of deep temporal fascia and deep temporal fat pad to protect the frontal branch of facial nerve. The deep layer is left attached to the muscle. (dDTF, deep layer of the deep temporal fascia; sDTF, superficial layer of the deep temporal fascia)Fig. 11.7 Exposing the lateral orbital rim and zygomatic arch.The superficial layer of the temporalis fascia is raised along with the contiguous periosteum of the zygomatic process of the frontal bone and the zygomatic arch. (dDTF, deep layer of the deep temporal fascia; sDTF, superficial layer of the deep temporal fascia; Zy, zygoma)Fig. 11.8 Vascularized pericranial flap.The vascularized pericranial flap can be used to seal off an opening into a lateral extension of the frontal sinus should that sinus be opened. (dDTF, deep layer of the deep temporal fascia; PO, periosteum; sDTF, super cial layer of the deep temporal fascia; Zy, zygoma)Fig. 11.9 Elongated pericranial flap.The pericranial flap can be made quite large by raising the surrounding skin through the subgaleal plane. The flap can be elon-gated with a back cut so as to reach openings in the skull base. A well-developed sphenoid sinus may be opened when drilling through the bone anterior to the lateral loop of the trigeminal nerve. The eustachian tube may be opened when drilling lateral to the intrapetrous segment of the carotid artery. (PO, periosteum)Fig. 11.10 Exposure of lateral orbital rim, zygomatic arch, and masseter muscle.Following the plane of the super cial temporal fascia will lead to a subosteal dissection of the zygoma. This dissection plane is continued over the orbital rim. (dDTF, deep layer of the deep temporal fascia; sDTF, super cial layer of the deep temporal fascia; Zy, zygoma)Fig. 11.11 Zygomaticofacial foramen.The zygomaticofacial nerve, one of the two branches of the zygomatic nerve, passes through the zygomaticofacial foramen. Injury to this nerve results in numbness of the scalp lateral to the orbit. (ZFF, zygomaticofacial foramen)Fig. 11.12 (Step 3) Landmarks for the osteotomy of the zygomatic arch.A limited zygomatic osteotomy allows the temporalis muscle to be raised anteriorly and inferiorly. This allows the surgeon to see parallel to the floor at the pole of the anterior middle fossa with minimal temporal lobe retraction. The posterior osteotomy is made obliquely through the root of the zygoma tangential to the glenoid fossa. The anterior osteotomy is made parallel to the orbit. The osteotomy begins at the marginal tubercle and should avoid the zygomaticofacial foramen. (MP, marginal process)Fig. 11.13 Freeing the marginal tubercle.The deep layer of the temporal fascia is separated from the undersurface of the zygomatic arch. (MP, marginal process)Fig. 11.14 Detaching the zygomatic arch.Osteotomies through the zygoma free a bone that resembles the bone of a T-bone steak. This bone is referred to as the “T” bone. The anterior cut is made parallel with the bony orbit and the posterior cut is made obliquely, parallel to the zygomatic root. A cut through the maxillary process frees the bone.Fig. 11.15 Raising the “T” boneThe “T” bone cut from the zygomatic arch is reflected inferiorly and left attached to the masseteric muscle. Leaving the bone attached to the masseteric muscle diminishes postoperative pain and provides the bone with a blood supply.Fig. 11.16 Inferior reflection of the temporalis muscle.The muscle is reflected through the opening created by the osteotomy. The muscle remains attached to its insertion onto the mandible. The muscle belly is not cut. The temporalis muscle is simply detached from the lateral skull. Care is taken not to injure the innervation and vasculature that lies on the undersurface of the muscle. Thus we raise the muscle with a sharp elevator and minimize cautery to the undersurface of the muscle. Oblique holes are drilled along the temporal line to reattach the muscle at the end of the case. (TM, temporalis muscle)Fig. 11.17 Deep temporal arteries and nerve.The deep temporal arteries and nerve that supply vasculature and innervation to the temporalis muscle are seen on the undersurface of the muscle. Damage to these structures can result in atrophy of the temporalis muscle. (aDTA, anterior deep temporal artery; pDTA, posterior deep temporal artery; TM, temporalis muscle)Fig. 11.18 (Step 4) Orbitotemporal detachment (beginning of a “golf-club” drilling).A hole is made in the greater wing of the sphenoid bone parallel to the roof of the orbit exposing the temporal and frontal dura with a coarse or extra coarse diamond drill,. The site of this hole is located at the depression between the middle and anterior fossa. Removing this bone exposes the lateral orbital wall and the frontal and temporal dura. This hole resembles the head of a golf club. This hole allows the surgeon to separate the frontal and temporal dura from the bone flap. It is dif cult to cut through the greater wing of the sphenoid with a craniotome. (FD, frontal dura; LOW, lateral orbital wall; TD, temporal dura)Fig. 11.19 Identification of the anterior division of the middle meningeal artery.The anterior division of the middle meningeal artery is seen passing under the greater wing of the sphenoid. (FD, frontal dura; LOW, lateral orbital wall; TD, temporal dura)Fig. 11.20 Subtemporal groove drilling (completion of the “golf-club” drilling).Beginning at the hole made in the lateral greater wing of the sphenoid bone, a groove is drilled through the lateral wall and floor of the middle fossa. By drilling this groove the surgeon is able to reach the margins of the middle fossa, which cannot be easily reached with a craniotome. The shape of the keyhole (a head) and this subtemporal groove (a shaft) resembles a bent golf club.Fig. 11.21 Frontotemporal craniotomy.A frontotemporal craniotomy is turned using a craniotome connecting the two ends of the “golf club.” Additional bur holes are made if the dura is tenaciously adherent to the bone.Fig. 11.22 Reflecting the craniotomy.The root of the zygoma will serve as a guide to the middle fossa. The anterior margin of the root of the zygoma is directly lateral to the foramen ovale; the midpoint of the root of the zygoma is lateral to the foramen spinosum; the posterior root is lateral to the geniculate ganglion (see Figs. 12.10 and 12.11).Fig. 11.23 (Step 5) Bony protrusion of temporal base (landmark for the lateral loop).Characteristically a bony protrusion is found lateral to the lateral loop of the trigeminal nerve. This protrusion should be burred flat. Furthermore, the bony ridges coming from the floor of the middle fossa should be removed with a diamond drill so as not to obstruct the surgeon’s line of sight. (MSR, mid-subtemporal ridge)Fig. 11.24 Foramen rotundum (V2).The foramen rotundum is seen anterior to the tip of the temporal dura and just lateral to the inferior end of the superior orbital ssure. (MSR, mid-subtemporal ridge; V2, maxillary nerve [second division of the trigeminal nerve])Fig. 11.25 Middle meningeal artery.The middle meningeal artery can be followed to the foramen spinosum. (MMA, middle meningeal artery)Fig. 11.26 Foramina ovale (V3) and spinosum (MMA).The foramen spinosum is frequently hidden under the protuberance of bone. It is found below the midzygomatic root. This foramen can always be localized by following the middle meningeal artery inferiorly along the dura. The foramen ovale lies anterior and medial to the foramen spinosum. (MMA, middle meningeal artery; V3, mandibular nerve )Fig. 11.27 (Step 6) Lateral loop formed by the maxillary and mandibular nerves.The dura propria is dissected from the maxillary nerve, the mandibular nerve, and the gasserian ganglion. Lifting the dura that covers the temporal lobe from the dura that covers the maxillary and mandibular nerves reveals the lateral loop, which connects those two nerves. Numerous veins connecting the pterygoid venous plexus and the cavernous sinus pass along those nerves. Venous bleeding is controlled by pushing hemostatic oxidized cellulose into the venous channels. Coagulation is limited to avoid facial paresthesia. (MMA, middle meningeal artery; MSR, mid-subtemporal ridge; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.28 (Step 7) Sacrifice of middle meningeal artery.The middle meningeal artery is ligated to allow the dura over the temporal lobe to be mobilized from the floor of the middle fossa. (MMA, middle meningeal artery; V3, mandibular nerve )Fig. 11.29 Elevating the dura propria.The dura propria is elevated from the lateral loop of the trigeminal nerve. (MMA, middle meningeal artery; MSR, mid-subtemporal ridge; LL, lateral loop; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.30 Skeletonizing the foramen rotundum and ovale.This maneuver frees the maxillary and mandibular nerves. The foramen rotundum and ovale are enlarged following the maxillary and mandibular nerves through the skull. These nerves appear to be coming up toward the surgeon as the canal is elongated. Drilling through the lateral loop leads to the pterygoid process of the sphenoid bone. Care should be taken not to enter the sphenoid sinus when drilling along the maxillary nerve. (FO, foramen ovale; FR, foramen rotundum; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.31 (Step 8) Vidian canal (in the case of a poorly developed sphenoid sinus).The vidian canal is found by drilling into the bone outlined by the lateral loop. The vidian canal is seen inferior to the maxillary nerve. It passes through the body of the sphenoid bone superior to the medial and lateral pterygoid plate. It passes into the pterygopalatine space. If the sphenoid sinus is well developed, drilling toward the vidian canal can open the sphenoid sinus. (FO, foramen ovale; FR, foramen rotundum; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve ; VC, vidian canal)Fig. 11.32 Vidian canal (in the case of a moderately developed sphenoid sinus).When the sphenoid sinus is better developed, the vidian canal is pushed laterally. (FO, foramen ovale; FR, foramen rotundum; V2, maxillary nerve [second division of the trigeminal nerve]; VC, vidian canal)Fig. 11.33 Vidian canal after shrinkage of sphenoid sinus mucosa (in the case of a well-developed sphenoid sinus).The mucosa of the sphenoid sinus is seen below the maxillary nerve in this picture. The vidian canal is obscured by the redundant sphenoid mucosa. The canal travels lateral to the sphenoid sinus to enter the pterygopalatine fossa. The internal maxillary artery terminates in the pterygopalatine fossa. The nerve of the vidian canal innervates the pterygopalatine ganglion and communicates with branches of the maxillary nerve in that fossa. (mSS, mucosa of the sphenoid sinus; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve ; VC, vidian canal)Fig. 11.34 (Step 9) Unroofing the foramen rotundum.The foramen rotundum is unroofed following the maxillary nerve to the pterygopalatine fossa. Medial to the maxillary nerve we see the confluence of the superior and inferior ophthalmic veins as they enter the cavernous sinus. (FR, foramen rotundum; PPF, pterygopalatine fossa; V2, maxillary nerve [second division of the trigeminal nerve]; VN, vidian nerve)Fig. 11.35 Unroofing the foramen ovale.The foramen ovale is unroofed following V3 into the infratemporal fossa. (FO, foramen ovale; MMA, middle meningeal artery; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.36 Foramen ovale emissary vein.Several veins are found traveling along the mandibular nerve through the foramen ovale. These veins connect the rich pterygoid venous system with the cavernous sinus. Bleeding from these veins can usually be controlled by packing their lumen with hemostatic agents, then patiently applying gentle pressure. (FOEV, foramen ovale emissary vein; mSS, mucosa of the sphenoid sinus; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve ; VC, vidian canal)Fig. 11.37 Unroofing the vidian canal.The vidian canal and the maxillary nerve are followed distally into the pterygopalatine flssure. (FO, foramen ovale; FR, foramen rotundum; PPF, pterygopalatine fossa; V2, maxillary nerve [second division of the trigeminal nerve]; VN, vidian nerve)Fig. 11.38 Exposing the distal branches of the maxillary and mandibular nerves.The maxillary nerve is followed distally into the pterygopalatine fossa and the mandibular nerve is followed distally into the infratemporal fossa. The vidian nerve is seen just below the maxillary nerve. This specimen had a poorly developed sphenoid sinus. (ION, infraorbital nerve; sLPM, superior head of the lateral pterygoid muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.39 Exposing the branches of the mandibular nerve without removing the lateral pterygoid muscle.The mandibular nerve divides into an anterior and a posterior trunk. The anterior trunk supplies most of the motor branches of the mandibular nerve plus the buccal nerve (the only sensory nerve from this trunk, which provides sensation to the inner and outer cheeks. The posterior trunk supplies most of the sensory branches plus the mylohyoid nerve, the only motor branch of that trunk. (AT (V3), anterior trunk of the mandibular nerve; ATN, auriculotemporal nerve; BN, buccal nerve; DTN, deep temporal nerve; MN, masseteric nerve; sLPM, superior head of the lateral pterygoid muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.40 Beginning of the cartilaginous portion of the eustachian tube medial to the foramen spinosum.Drilling medial to the foramen spinosum and posterior to the foramen ovale and preserving the temporomandibular joint, the surgeon will encounter the eustachian tube. The carotid artery, which travels medial to the eustachian tube, turns medially toward the cavernous sinus under the lateral loop. (ATN, auriculo-temporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ET, eustachian tube; MN, masseteric nerve; V3, mandibular nerve )Fig. 11.41 Exposing the middle part of the cartilaginous eustachian tube.The cartilaginous portion of the eustachian tube is seen medial to the mandibular nerve under the lateral loop. (ATN, auriculo-temporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ET, eu stachian tube; sLPM, superior head of the lateral pterygoid muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.42 Exposing the branches of the maxillary and mandibular nerves.The maxillary and mandibular nerves are followed until they branch within the pterygopalatine flssure and infratemporal fossa, respectively. (ATN, auriculotemporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ION, infraorbital nerve; MN, masseteric nerve; sLPM, superior head of the lateral pterygoid muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve ; ZN, zygomatic nerve)Fig. 11.43 Identifying the branches of the maxillary nerve.The zygomatic branch, which enters the infraorbital flssure to innervate the temporal area behind the zygomaticofrontal process via in the zygomaticotemporal and zygomaticofacial nerves, branches off the maxillary nerve. The posterior superior alveolar nerve, which innervates the maxillary sinus and the molar teeth, branches from the maxillary nerve in the pterygopalatine fossa and runs in a slightly curved “S” shape toward the infraorbital sulcus or canal. The infraorbital nerve enters the inferior orbital flssure. (ION, infraorbital nerve; V2, maxillary nerve [second division of the trigeminal nerve]; ZN, zygomatic nerve)Fig. 11.44 Identifying the nerves in the pterygopalatine fossa.The pterygopalatine ganglion receives parasympathetic innervation from the vidian nerve and provides postganglionic fibers to the lacrimal gland and nasal mucosa. It is seen on the undersurface of V2. (GPN, greater palatine nerve; ION, infraorbital nerve; LPN, lesser palatine nerve; PPG, pterygopalatine ganglion; V2, maxillary nerve [second division of the trigeminal nerve]; ZN, zygomatic nerve)Fig. 11.45 Demonstrating the greater and lesser palatine nerves.The greater and lesser palatine nerves pass through the pterygopalatine ganglion to innervate the hard palate, adjacent gums, soft palate, and uvula. (GPN, greater palatine nerve; ION, infraorbital nerve; LPN, lesser palatine nerve; PPG, pterygopalatine ganglion; V2, maxillary nerve [second division of the trigeminal nerve]; VN, vidian nerve)Fig. 11.46 Artery of the foramen rotundum.The artery of the foramen rotundum is a branch of the internal maxillary artery. This artery may be an important blood supply for meningiomas of the middle fossa. (AFR, artery of the foramen rotundum; IOA, infraorbital artery; ION, infraorbital nerve; V2, maxillary nerve [second division of the trigeminal nerve]; ZN, zygomatic nerve)Fig. 11.47 Identifying the branches of the maxillary nerve.The posterior inferior nasal branches leave the pterygopalatine ganglion and pass through the palatine bone to innervate the inferior nasal concha. (IOA, infraorbital artery; ION, infraorbital nerve; V2, maxillary nerve [second division of the trigeminal nerve]; ZN, zygomatic nerve)Fig. 11.48 Identifying the branches of the maxillary nerve.A closeup view reveals branches of the maxillary nerve that innervate the pharynx and the nasal mucosa, the posterior nasal branches, the pharyngeal branches, and the pterygopalatine ganglion. (ION, infraorbital nerve; NPN, nasopalatine nerve; PPG, pterygopalatine ganglion; V2, maxillary nerve [second division of the trigeminal nerve]; VN, vidian nerve; ZN, zygomatic nerve)Fig. 11.49 Identifying the branches of the maxillary nerve.An overview of the maxillary nerve demonstrates the vidian nerve innervating the pterygopalatine ganglion, the greater and lesser palatine nerves, and posterior nasal branches. (GPN, greater palatine nerve; ION, infraorbital nerve; LPN, lesser palatine nerve; NPN, nasopalatine nerve; PPG, pterygopalatine ganglion; V2, maxillary nerve [second division of the trigeminal nerve]; VN, vidian nerve; ZN, zygomatic nerve)Fig. 11.50 Identifying the branches.A closeup view of the mandibular nerve demonstrates the anterior and posterior divisions. The deep temporal, masseteric, buccal, lateral pterygoid, auriculotemporal, inferior alveolar, and lingual nerves are defined. The nerve to the masseter passes over the lateral pterygoid muscle to innervate the masseter through the mandibular notch. The deep temporal nerve takes a similar course. The lateral pterygoid nerve enters the deep surface of that muscle. The buccal nerve passes between the superior and inferior heads of the lateral pterygoid muscle. The auriculotemporal nerve runs deep to the lateral pterygoid muscle and exits posterior to the mandible. Similarly, the lingual and the inferior alveolar nerves run deep to the lateral pterygoid and lateral to the medial pterygoid muscles. (AT (V3), anterior trunk of the mandibular nerve; ATN, auriculotemporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ET, eustachian tube; MN, masseteric nerve; NLPM, nerve to the lateral pterygoid muscle; sLPM, superior head of the lateral pterygoid muscle; TMJ, temporomandibular joint)Fig. 11.51 Identifying the branches of the mandibular nerve.Looking inferiorly we see the auriculotemporal, inferior alveolar, and lingual nerves. (AT (V3), anterior trunk of the mandibular nerve; ATN, auriculotemporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ET, eustachian tube; IAN, inferior alveolar nerve; LN, lingual nerve; MN, masseteric nerve; sLPM, superior head of the lateral pterygoid muscle; TMJ, temporomandibular joint)Fig. 11.52 (Step 10) Lateral and medial laminae of pterygoid process.Drilling into the pterygoid process, we can see the lateral and medial wings of the pterygoid process. (BN, buccal nerve; LPP, lateral lamina of the pterygoid plate; MPP, medial lamina of the pterygoid plate; (sLPM, superior head of the lateral pterygoid muscle; (V2, maxillary nerve [second division of the trigeminal nerve])Fig. 11.53 Superior head of lateral pterygoid muscle.The superior head of the lateral pterygoid muscle originates from the inferior lateral greater wing of the sphenoid bone and adjacent posterior maxilla. It inserts into the medial neck of the condyle of the mandible. (ATN, auriculotemporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ET, eustachian tube; MA, maxillary artery; MN, masseteric nerve; sLPM, superior head of the lateral pterygoid muscle; TMJ, temporomandibular joint; V3, mandibular nerve )Fig. 11.54 Branching of the mandibular nerve.The buccal nerve is seen in the interval between the superior and inferior heads of the lateral pterygoid muscle. The inferior head originates from the lateral surface of the lateral pterygoid plate and inserts into the neck of the mandible. (BN, buccal nerve; iLPM, inferior head of the lateral pterygoid muscle; NLPM, nerve to the lateral pterygoid muscle; sLPM, superior head of the lateral pterygoid muscle; V3, mandibular nerve )Fig. 11.55 Detaching the superior head of the lateral pterygoid muscle.The superior head of the lateral pterygoid muscle is detached from the greater wing of the sphenoid bone to provide a better view of the buccal nerve heading toward the buccinator. It mediates sensation of the mucosal surface of the cheek. (BN, buccal nerve; DTN, deep temporal nerve; ET, eustachian tube; iLPM, inferior head of the lateral pterygoid muscle; MA, maxillary artery; MN, masseteric nerve; NLPM, nerve to the lateral pterygoid muscle; sLPM, superior head of the lateral pterygoid muscle; TMJ, temporomandibular joint; V2, maxillary nerve [second division of the trigeminal nerve])Fig. 11.56 Identifying the lateral lamina of pterygoid process, medial pterygoid muscle, and maxillary artery.The superior and inferior heads of the lateral pterygoid muscles have been removed to demonstrate the medial and lateral plates of the pterygoid process and the internal maxillary artery. (BN, buccal nerve; ION, infraorbital nerve; LN, lingual nerve; LPP, lateral lamina of the pterygoid plate; MA, maxillary artery; MPM, medial pterygoid muscle; MPP, medial lamina of the pterygoid plate; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.57 Maxillary artery and mandibular nerve branches.Looking inferiorly we see the inferior alveolar nerve and the lingual nerve. (BN, buccal nerve; ET, eustachian tube; IAN, inferior alveolar nerve; LN, lingual nerve; LPP, lateral lamina of the pterygoid plate; MA, maxillary artery; MPM, medial pterygoid muscle; MPP, medial lamina of the pterygoid plate; V3, mandibular nerve )Fig. 11.58 Identifing the chorda tympani joining the lingual nerve.The chorda tympani, which has exited the skull adjacent to the spine of the sphenoid bone, is seen joining the lingual nerve. CT, chorda tympani; IAN, inferior alveolar nerve; LN, lingual nerve; MA, maxillary artery)Fig. 11.59 Chorda tympani joining the lingual nerve.The chorda tympani runs medial to the inferior alveolar nerve. (CT, chorda tympani; IAN, inferior alveolar nerve; LN, lingual nerve; MA, maxillary artery)Fig. 11.60 The otic ganglion.The otic ganglia receives innervation from the lesser petrosal nerve (branch of cranial nerve IX) and supplies parasympathetic innervation to the parotid gland via the auriculotemporal nerve. (AT (V3), anterior trunk of the mandibular nerve; ATN, auriculo-temporal nerve; BN, buccal nerve; DTN, deep temporal nerve; ET, eustachian tube; IAN, inferior alveolar nerve; LN, lingual nerve; MMA, middle meningeal artery; MN, masseteric nerve; OG, otic ganglion)Fig. 11.61 The medial pterygoid nerve.The medial pterygoid nerve branches very proximally off the main trunk of the mandibular nerve. It innervates the tensor velli palatini and tensor tympani muscles. (AT (V3), anterior trunk of the mandibular nerve; ATN, auriculotemporal nerve; BN, buccal nerve; IAN, inferior alveolar nerve; LN, lingual nerve; MA, maxillary artery; NMPM, nerve to the medial pterygoid muscle)Fig. 11.62 Lateral loop, maxillary and mandibular nerve branches, and maxillary artery.Branches of the mandibular nerve and adjacent structures in the infratemporal fossa are shown. (BN, buccal nerve; ET, eu stachian tube; LN, lingual nerve; LPP, lateral lamina of the pterygoid plate; MA, maxillary artery; MPM, medial pterygoid muscle; PBF, pharyngobasilar fascia; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.63 Removing the maxillary artery and exposing the tensor velli palatine.The tensor velli palatini muscle lies medial to the medial pterygoid muscle. It originates from the upper medial pterygoid plate and spine of the sphenoid bone. (AT (V3), anterior trunk of the mandibular nerve; BN, buccal nerve; ET, eustachian tube; IAN, inferior alveolar nerve; LN, lingual nerve; LPP, lateral lamina of the pterygoid plate; MPM, medial pterygoid muscle; NMPM, nerve to the medial pterygoid muscle; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle; V2, maxillary nerve [second division of the trigeminal nerve])Fig. 11.64 Removing the lateral lamina of the pterygoid process.Removing the lateral plate of the pterygoid process demonstrates the deep head of the medial pterygoid muscle, which originates from the medial surface of the lateral pterygoid plate, and the origin of the tensor velli palatini muscle from the base of the pterygoid plate. (ET, eustachian tube; LN, lingual nerve; MPM, medial pterygoid muscle; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.65 Partially removing the medial pterygoid muscle.Partially removing the medial pterygoid muscle exposes the medial lamina of the pterygoid process and the tensor velli palatini muscle. The eustachian tube enters the pharynx adjacent to that muscle. (ET, eustachian tube; MPP, medial lamina of the pterygoid plate; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.66 Medial lamina of pterygoid process.The medial lamina of the pterygoid process is dissected from the eustachian tube. (ION, infraorbital nerve; MPP, medial lamina of the pterygoid plate; TVPM, tensor velli palatini muscle; V3, mandibular nerve )Fig. 11.67 Removing the medial lamina of the pterygoid process.Removing the medial lamina of the pterygoid process exposes the cartilaginous portion of the eustachian tube and its entrance into the nasopharynx. (ET, eustachian tube; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.68 (Step 11) Direction of eustachian tube.The cartilaginous portion of the eustachian tube originates at the junction between the squamous and petrous portions of the temporal bone and ends in the nasal portion of the pharynx under the tensor velli palatini muscle. (ET, eustachian tube; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.69 The eustachian tube and the tensor velli palatini muscle.The eustachian tube enters the pharynx under the tensor velli palatini muscle. (ET, eustachian tube; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.70 (Step 11) Posterior translocation of V3.The tensor velli palatini muscle and the cartilaginous portion of the eustachian tube are exposed after the mandibular nerve is posteriorly translocated. (ET, eustachian tube; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle)Fig. 11.71 Beginning removal of the tensor velli palatini muscle.The tensor velli palatini is removed in a stepwise fashion. (ET, eustachian tube; PBF, pharyngobasilar fascia; TVPM, tensor velli palatini muscle)Fig. 11.72 Removing the tensor velli palatini muscle.This exposes the eustachian tube and the superior constrictor of the pharynx. (ET, eustachian tube; LVPM, levator velli palatini muscle; PBF, pharyngobasilar fascia; SPCM, superior pharyngeal constrictor muscle)Fig. 11.73 The levator velli palatini muscle.The levator velli palatini muscle originates from the petrous portion of the temporal bone and passes deep into the entrance of the eustachian tube into the pharynx. (ET, eustachian tube; LVPM, levator velli palatini muscle)Fig. 11.74 Opening the eustachian tube into the nasopharynx.The eustachian tube is opened so that the anatomical relationship of the nasopharynx and the infratemporal fossa can be demonstrated. (ET, eustachian tube; LVPM, levator velli palatini muscle; NP, nasopharynx; PBF, pharyngobasilar fascia; SPCM, superior pharyngeal constrictor muscle)Fig. 11.75 Direction of the eustachian tube.The dissector is inserted so that a course of the eustachian tube is indicated. (ET, eustachian tube; LVPM, levator velli palatini muscle; NP, nasopharynx; PBF, pharyngobasilar fascia; SPCM, superior pharyngeal constrictor muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.76 The pterygoid hamulus.The pterygoid hamulus serves as a pulley for the tendon of the tensor velli palatini muscle. (ET, eustachian tube; NP, nasopharynx; PH, pterygoid hamulus; SPCM, superior pharyngeal constrictor muscle)Fig. 11.77 Exposing the infratemporal and pterygoid fossae.The infratemporal and pterygoid fossae are completely exposed. (ET, eustachian tube; LOW, lateral orbital wall; NP, nasopharynx; PBF, pharyngobasilar fascia; SPCM, superior pharyngeal constrictor muscle; TM, temporalis muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.78 The maxillary sinus.A bony opening on the opposite side of the pterygopalatine flssure takes the surgeon into the maxillary sinus. (ET, eustachian tube; ION, infraorbital nerve; MS, maxillary sinus; MT, maxillary tuberosity; NP, nasopharynx; PBF, pharyngobasilar fascia; V3, mandibular nerve )Fig. 11.79 Magnified view of the anterior infratemporal fossa approach.Magnifled view of the infratemporal fossa and adjacent structures. (ET, eustachian tube; ION, infraorbital nerve; LVPM, levator velli palatini muscle; MS, maxillary sinus; MT, maxillary tuberosity; NP, nasopharynx; PBF, pharyngobasilar fascia; SPCM, superior pharyngeal constrictor muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )Fig. 11.80 Final view of the anterior infratemporal fossa approach.The final view of the anterior infratemporal fossa approach exposes the infratemporal and pterygoid fossae. (ET, eustachian tube; ION, infraorbital nerve; ITF, infratemporal fossa; LOW, lateral orbital wall; MS, maxillary sinus; NP, nasopharynx; PBF, pharyngobasilar fascia; PPF, pterygopalatine fossa; SPCM, superior pharyngeal constrictor muscle; TM, temporalis muscle; V2, maxillary nerve [second division of the trigeminal nerve]; V3, mandibular nerve )
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Jul 19, 2020 | Posted by drzezo in NEUROSURGERY | Comments Off on 11 Preauricular Transzygomatic Approach to the Anterior Infratemporal Fossa and Middle Infratemporal Fossa
