Anatomical Variants of Post-ganglionic Fibers within the Pterygopalatine Fossa: Implications for Endonasal Skull Base Surgery

Abstract Objectives The vidian nerve provides parasympathetic innervation to the nasal cavity and the lacrimal gland. Previous anatomic studies have primarily focused on preservation or severance of the vidian nerve proximal to the pterygopalatine ganglion (PPG). This study aimed to assess its neural fibers within the pterygopalatine fossa after synapsing at the PPG, and to explore potential clinical implications for endoscopic endonasal skull base surgery. Methods An endonasal transpterygoid approach was performed on eight cadaveric specimens (16 sides). The PPG and maxillary nerve within the pterygopalatine fossa were divided. The vidian nerve was traced retrograde into the foramen lacerum, and postganglionic fibers distal to the PPG were dissected following the zygomatic nerve into the orbit. Potential communicating branches between the ophthalmic nerve (V1) and the PPG were also explored. Results All sides showed a plexus of neural communications between the PPG and the maxillary nerve. The zygomatic nerve exits the maxillary nerve close to the foramen rotundum, piercing the orbitalis muscle to enter the orbit in all sides. The zygomatic nerve was identified running beneath the inferior rectus muscle toward a lateral direction. In 7/16 sides (43.75%), a connecting branch between V1 and the pterygopalatine ganglion was observed. Conclusion Neural communications between the PPG and the maxillary nerve were present in all specimens. A neural branch from V1 to the PPG potentially contributes additional postganglionic parasympathetic function to the lacrimal gland.

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Pterygopalatine Fossa: Microsurgical Anatomy and its Relevance for Skull Base Surgery

Arquivos Brasileiros de Neurocirurgia Brazilian Neurosurgery ◽

10.1055/s-0040-1718430 ◽

2020 ◽

Author(s):

Gustavo Rassier Isolan ◽

Julio Mocellin Bernardi ◽

João Paulo Mota Telles ◽

Nícollas Nunes Rabelo ◽

Eberval Gadelha Figueiredo

Keyword(s):

Skull Base ◽

The Body ◽

Pterygopalatine Fossa ◽

Surgical Approaches ◽

Maxillary Artery ◽

Microsurgical Anatomy ◽

Extensive Resection ◽

Maxillary Nerve ◽

Adjacent Structures ◽

Surgical Field

Abstract Introduction The purpose of this study was to define the anatomical relationships of the pterygopalatine fossa (PPF) and its operative implications in skull base surgical approaches. Methods Ten cadaveric heads were dissected at the Dianne and M Gazi Yasargil Educational Center MicrosurgicaLaboratory, in Little Rock, AK, USA. The PPF was exposed through an extended dissection with mandible and pterygoid plate removal. Results The PPF has the shape of an inverted cone. Its boundaries are the pterygomaxillary fissure; the maxilla, anteriorly; the medial plate of the pterygoid process, and greater wing of the sphenoid process, posteriorly; the palatine bone, medially; and the body of the sphenoid process, superiorly. Its contents are the maxillary division of the trigeminal nerve and its branches; the pterygopalatine ganglion; the pterygopalatine portion of the maxillary artery (MA) and its branches; and the venous network. Differential diagnosis of PPF masses includes perineural tumoral extension along the maxillary nerve, schwannomas, neurofibromas, angiofibromas, hemangiomas, and ectopic salivary gland tissue. Transmaxillary and transpalatal approaches require extensive resection of bony structures and are narrow in the deeper part of the approach, impairing the surgical vision and maneuverability. Endoscopic surgery solves this problem, bringing the light source to the center of the surgical field, allowing proper visualization of the surgical field, extreme close-ups, and different view angles. Conclusion We provide detailed information on the fossa's boundaries, intercommunications with adjacent structures, anatomy of the maxillary artery, and its variations. It is discussed in the context of clinical affections and surgical approaches of this specific region, including pterygomaxillary disjunction and skull base tumors.

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Simplifying Access to the Lateral Sphenoid Recess: A Modification of the Transpterygoid Approach

American Journal of Rhinology and Allergy ◽

10.1177/19458924211003813 ◽

2021 ◽

pp. 194589242110038

Author(s):

Satyan B. Sreenath ◽

Dennis M. Tang ◽

João Paulo De Almeida ◽

Pranay Soni ◽

Troy D. Woodard ◽

...

Keyword(s):

Skull Base ◽

Sphenoid Sinus ◽

Postoperative Morbidity ◽

Pterygopalatine Fossa ◽

Benign Lesions ◽

Lateral Recess ◽

Less Invasive ◽

Vidian Nerve ◽

The Face ◽

Skull Base Defect

Background Meningoencephaloceles originating in the lateral recess of the sphenoid sinus can be difficult to access. Historically, the endoscopic transpterygoid approach was advocated, which carries additional morbidity given the dissection of the pterygopalatine fossa (PPF) contents to provide a direct line approach to the defect. Given our increased facility with angled endoscopes and instrumentation, we now approach this region in a less invasive manner. Methods We describe the endoscopic modified transpterygoid approach (MTPA), a quicker approach to the lateral sphenoid recess which preserves the PPF contents through a single nostril corridor. Results In the MTPA, the face of the sphenoid and anterior junction of the pterygoid plates are removed, allowing for mobilization of the PPF contents with the periosteum intact. Angled instrumentation is then used to resect the meningoencephalocele and repair the skull base defect in the lateral recess. If increased exposure is needed, this can be gained by sacrificing the sphenopalatine artery and even the vidian nerve, although this is rarely required. Conclusions The MTPA obviates the need for PPF dissection and simplifies access to the lateral sphenoid recess while minimizing postoperative morbidity. This approach should be considered for accessing meningoencephaloceles and other benign lesions in this challenging location.

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Finding the Petroclival Carotid Artery: The Vidian–Eustachian Junction as a Reliable Landmark

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0037-1608650 ◽

2017 ◽

Vol 79 (04) ◽

pp. 361-366 ◽

Cited By ~ 2

Author(s):

Gretchen Oakley ◽

Jareen Ebenezer ◽

Aneeza Hamizan ◽

Peta-Lee Sacks ◽

Darren Rom ◽

...

Keyword(s):

Carotid Artery ◽

Skull Base ◽

Internal Carotid ◽

Skull Base Surgery ◽

Infratemporal Fossa ◽

Case Series ◽

Vidian Nerve ◽

Fresh Frozen ◽

Relationship Of ◽

The Relationship

Introduction Identifying the internal carotid artery (ICA) when managing petroclival and infratemporal fossa pathology is essential for the skull base surgeon. The vidian nerve and eustachian tube (ET) cartilage come together at the foramen lacerum, the vidian–eustachian junction (VEJ). The ICA position, relative to the VEJ is described. Methods Endoscopic dissection of adult fresh-frozen cadaver ICAs and a case series of patients with petroclival pathology were performed. The relationship of the VEJ to the ICA horizontal segment, vertical segment, and second genu was assessed. The distance of the ICA second genu to VEJ was determined in coronal, axial, and sagittal planes. The length of the vidian nerve and ET was measured from the pterygopalatine fossa (PPF) and nasopharyngeal orifice to the VEJ. Results In this study, 10 cadaver dissections (82.3 ± 6.7 years, 40% female) were performed. The horizontal petrous ICA was at or behind VEJ in 100%, above VEJ in 100%, and lateral to VEJ in 80%. The vertical paraclival segment was at or behind VEJ in 100%, above in 100%, and medial in 100%. The second genu was at or behind VEJ in 100% (3.3 ± 2.4 mm), at or above in 100% (2.5 ± 1.6 mm), and medial in 100% (3.4 ± 2.0 mm). The VEJ was successfully used to locate the ICA in nine consecutive patients (53.3 ± 13.6 years, 55.6% female) where pathology was also present. The VEJ was 15.0 ± 6.0 mm from the ET and 17.4 ± 4.1 mm from the PPF. Conclusion The VEJ is an excellent landmark as it defines both superior and posterior limits when isolating the ICA in skull base surgery.

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