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)

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  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.

  
  
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  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 ).

  
  
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  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.

  
  
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  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.

  
  
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  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.

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

  
  
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  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

  
  
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  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 ).

  
  
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  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 ).

  
  
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  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 ).

  
  
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  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 ).

  
  
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  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 ).