Lateral sublabial endoscopic approach to foramen ovale: a novel endoscopic technique to access infratemporal fossa.

Objective: Our aim was to define a novel endoscopic approach to selectively access the foramen ovale through the lateral sublabial route.

Methods: Lateral sublabial endoscopic approach to the foramen ovale was studied in 3 fresh cadavers. A 2.5-cm sublabial submucosal incision gained access to the foramen ovale through the corridor under the zygomatic process of maxilla and lateral to the pterygoid plate. To display the anatomic principles of the lateral sublabial endoscopic approach, the surgical anatomy of the endoscopic corridor and the neurovascular structures around the foramen ovale were studied and documented.

Results: Lateral sublabial endoscopic approach provided access to the foramen ovale and related neurovascular structures at the posterolateral part of the sphenoid bone without any bone resection. The branches of the pterygoid segment of the maxillary artery superficial to the lower and upper heads of the pterygoid muscles were exposed initially through the endoscopic corridor under the zygoma and lateral to the pterygoid plate. The buccal nerve, passing in between the 2 heads of the lateral pterygoid muscle and the lingual and inferior alveolar branches of the V3 segment of the trigeminal nerve, emerging from under the cover of the lower head of the lateral pterygoid muscle were exposed deep to the branches of the maxillary artery. Following the inferior alveolar nerve backward proximally under the lower head of the pterygoid muscle exposes the foramen ovale.

Conclusions: Lateral sublabial endoscopic approach, a minimally invasive route to the foramen ovale, requires no bone removal and provides adequate exposure to a hard-to-reach area in the infratemporal fossa. With the advantage of visualizing the distal segment of the maxillary artery and the segments of the mandibular nerve, early in the procedure, the approach can provide a controlled endoscopic manipulation for accessing this region.