Chapter 23 Jugular Foramen Approach



10.1055/b-0037-143529

Chapter 23 Jugular Foramen Approach

Muhamad A. Amine, Vijay K. Anand, Tomasz Dziedzic, Theodore H. Schwartz

Introduction


The jugular foramen (JF) is a complicated area to access regardless of the approach or technique used. The endoscopic transmaxillary transpterygoid approach1 can be extended to access the parapharyngeal space (PPS) and JF contained therein.2,3 The technique will be demonstrated here using a step-by-step cadaveric dissection. It is important to understand the regional anatomy and correlate it with the dissection, which requires wide exposure starting with a broad septectomy to prevent injury to vital structures. Using a 30-degree scope in the contralateral naris allows for the most comfortable positioning of instruments and optimal view of the area of dissection. All documentation and illustrations in this chapter were obtained using a 30-degree scope. It should also be noted that all the images within this chapter were obtained from the same cadaveric specimen on the left side. A secure attempt has been made to obtain the images using the same point of view to demonstrate a “flip-book” like series of images showing the stepwise dissection. However, once the PPS was exposed, close-up images were taken to demonstrate the detailed anatomy.



23.1 Indications


Endoscopic approach to the JF includes neoplastic lesions such as trigeminal schwannomas, nasopharyngeal cancers, juvenile angiofibromas, and meningiomas, which extend to or invade the middle cranial or infratemporal fossa (ITF). The main benefit of this approach is a direct approach which spares the risk of facial nerve injury, temporomandibular and mandibular resection, and middle and external ear obliteration as seen in the traditional lateral approaches. However, the endoscopic approach is not without its own potential morbidities which stem from the resection of the pterygoid musculature and risk of injury to the intimate neurovascular structures including the carotid artery and cranial nerves V, IX, X, XI, and XII as well as the sympathetic chain as they emerge from the skull base within the PPS. Nevertheless, the endonasal approach offers a direct route to the jugular area and allows for the management of the entire ITF and superior PPS.



23.2 Surgical Steps (Including Tips and Tricks, Technique, and Important Landmarks)




  • Create a wide septectomy to allow for a binostril approach. A 30-degree scope is placed in the contralateral side, while the instruments can be placed in either side.



  • The middle turbinate is removed and a medial maxillectomy is performed down to the floor of the nose. The inferior turbinate is also removed. The entire back wall, lateral wall, and roof of the maxillary sinus are in view ( Fig. 23.1 ).



  • Next, the back wall of the maxillary sinus is removed ( Fig. 23.2 ). This exposes the pterygopalatine fossa (PPF) and ITF contents. The periosteal fascial layer is removed and the internal maxillary artery is ligated carefully so as not to injure the infraorbital nerve (ION) laterally and superiorly. The ION serves as our landmark as it courses posteriorly toward the infraorbital foramen. It also gives and receives branches to the pterygopalatine ganglion which lies within the PPF.



  • To gain access to the posterior contents of the PPF and ITF, the vascular and fatty contents of the anterior compartment are carefully removed ( Fig. 23.3 ). This will then expose two important muscles, the temporalis muscle (TM) and the lateral pterygoid muscle (LPM). Another important landmark that is exposed is the buccal nerve (BN). The BN is found lying between the TM and LPM. Following it posteriorly will lead you to the foramen ovale (FO) and the root of the third division of the trigeminal nerve.



  • Next, the inferior head of the LPM must be resected ( Fig. 23.4 ). The BN is seen running between the upper and lower heads of the LPM.



  • The lateral pterygoid plate (LPP) is then resected to reveal the medial pterygoid muscle (MPM) ( Fig. 23.4 ).



  • The LPP must be removed up to the skull base ( Fig. 23.5 ). This will expose the FO as it lies just posterior to it. Again, the BN is traced posteriorly as it will lead to the mandibular nerve. The inferior portion of the LPP serves as landmark for the internal carotid artery (ICA) in the sagittal plane.4



  • The LPM is removed as much as possible. Medially, one will see the MPM and the tensor veli palatini muscle (TVPM). These two muscles are seen running almost perpendicularly ( Figs. 23.6 and 23.7 ).



  • The TVPM is then resected and the cartilaginous eustachian tube (ET) is then visualized posterolateral to it running in the direction of the middle ear ( Fig. 23.8 ).



  • The TVPM is resected inferiorly to visualize the levator veli palatini muscle (LVPM) which runs in the same direction as the ET ( Fig. 23.9 ). The LVPM is an important landmark as it will lead us to the PPS ( Fig. 23.10 ).



  • The mandibular nerve (V3) is lateralized and will reveal the fatty contents of the prestyloid space within the PPS ( Fig. 23.11 ). Removal of the fatty contents will reveal the stylopharyngeal muscle which separates the pre- and poststyloid spaces. The fascial of the carotid sheath can be seen as you dissect into the poststyloid space ( Fig. 23.11 ).



  • The poststyloid space is dissected, revealing the cranial nerves and the JF is seen posterior and lateral to the ICA ( Figs. 23.12 and 23.13 ). The cranial nerves and the sympathetic chain run in between the ICA and the JF ( Fig. 23.14 ).

Fig. 23.1 Left maxillary sinus. The inferior and middle turbinates have been resected. A wide antrostomy is performed down to the level of the nasal floor and posteriorly to the posterior wall of the maxillary sinus. The infraorbital nerve (ION) is in view laterally and superiorly. The sphenopalatine artery (SPA) is exposed and ligated at the sphenopalatine foramen.
Fig. 23.2 The sphenopalatine artery (SPA) is identified and followed and exposed proximally by removing the posterior wall of the maxillary sinus using Kerrison rongeurs and bone curettes. By removing the posterior wall of the maxillary sinus, the pterygopalatine fossa (PPF) and infratemporal fossa (ITF) are entered. The anterior compartment of the PPF contains periosteal fascia (F), adipose (A), and branches of the internal maxillary artery (IMA). The entire posterior wall, the underlying fascia, fat, and the vasculature must be removed to provide a wide exposure. NP, nasopharynx.
Fig. 23.3 Following removal of the internal maxillary artery branches and fat, the temporalis (TM) and lateral pterygoid (LPM) muscles can be seen. An important landmark to note is the buccal nerve (BN) that is found running between these two muscles. IMA, internal maxillary artery; ION, infraorbital nerve.
Fig. 23.4 The inferior head of the lateral pterygoid muscle (LPMi) must be removed. The superior head (LPMs) is in view here. The buccal nerve (BN) is followed proximally and is seen running between the upper and lower heads of the lateral pterygoid muscle. The lateral pterygoid plate (LPP) has been partially resected to reveal the medial pterygoid muscle (MPM).
Fig. 23.5 The lateral pterygoid plate (LPP) has been resected up to the skull base (SB) except for the inferior portion. The lateral pterygoid plate serves as a landmark for the internal carotid artery because it lies in the same sagittal plane.4 The medial pterygoid muscle (MPM) is in view. The resection of the lateral pterygoid plate and muscle enables the dissection of the buccal nerve all the way back to the foramen ovale. BN, buccal nerve; LPMi, lateral pterygoid muscle inferior head; LPMs, lateral pterygoid muscle superior head; MPP, part of the medial pterygoid plate that has been removed.
Fig. 23.6 (a) View after further resection of the lateral pterygoid muscle (LPM). The posterior division of the mandibular nerve (V3), which contains predominantly afferent fibers, is seen coming from the area of the foramen ovale. The medial pterygoid muscle (MPM) can be seen here running from the pterygoid fossa, posteriorly, laterally, and inferiorly as it will insert on the medial surface of the mandibular angle. Just medial to it and running perpendicularly, the tensor veli palatini muscle (TVPM) with its overlying fascia can be seen. (b) Close-up picture of the medial pterygoid muscle and the tensor veli palatini muscle. LPP, lateral pterygoid plate.
Fig. 23.7 (a) The tensor veli palatini muscle (TVPM) is seen here originating from the scaphoid fossa of the pterygoid process and medial aspect of the spine. The overlying fascia has been partially removed. The buccal nerve (BN) and posterior division of the mandibular nerve (V3) can be seen as they go toward the foramen ovale. (b) Close-up view of the same.
Fig. 23.8 The tensor veli palatini muscle (TVPM) is resected revealing the cartilaginous eustachian tube (ET). The ET runs from the nasopharynx to the middle ear in a posterior, lateral, and superior direction. It enters the skull base anterior to the internal carotid artery. The mandibular nerve (V3) and its branches are being retracted laterally.
Fig. 23.9 Further removal of the tensor veli palatini muscle inferiorly reveals the levator veli palatini muscle (LVPM). ET, eustachian tube; V3, mandibular nerve.
Fig. 23.10 Panoramic view of the dissection demonstrating the structures and landmarks that can be visualized in the parapharyngeal space. The branches of V3 can be seen. The middle meningeal artery (MMA) is seen immediately posterior to the foramen ovale (FO). The levator veli palatini muscle (LVPM) can be seen.
Fig. 23.11 (a) Zoomed-out view of the parapharyngeal space (PPS) with the fatty contents of the prestyloid space in view. (b) Zoomedin view of the parapharyngeal space. By dissecting through the prestyloid compartment, the stylopharyngeal muscle (SPM) can be seen which divides the prestyloid and poststyloid spaces. LVPM, levator veli palatini muscle. (c) Once the fat has been removed from the prestyloid space, the fascia of the carotid sheath (CS) comes into view. (d) The carotid sheath is opened and the internal carotid artery (ICA) is exposed.
Fig. 23.12 The internal carotid artery (ICA) is exposed in the poststyloid parapharyngeal space. The nasopharynx (NP), V3 from the foramen ovale (FO), maxillary sinus floor (MS), eustachian tube (ET), and lateral pterygoid plate (LPP) are all shown to demonstrate the location of the internal carotid artery relative to these anatomic landmarks.
Fig. 23.13 (a) The poststyloid space is dissected revealing the cranial nerves, and the jugular foramen (JF) is seen posterior and lateral to the internal carotid artery (ICA). (a) Zoomed-out image which now demonstrates the ascending pharyngeal artery (APA) coursing in close contact with the internal carotid artery. The levator veli palatini muscle (LVPM) is also seen coursing in the same direction as the eustachian tube. IX, glossopharyngeal nerve; X, vagus nerve.
Fig. 23.14 Internal carotid artery (ICA), sympathetic chain (SC), and CNs IX, X, XI, and XII are seen as they course between the carotid artery and the jugular foramen (JF).

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May 27, 2020 | Posted by in NEUROSURGERY | Comments Off on Chapter 23 Jugular Foramen Approach

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