The Endoscopic Paramandibular Window to the Infratemporal Fossa: Surgical Anatomy and Expanding Clinical Indications

Objective: The medial paramandibular window has recently been described as an endoscopic corridor for exploring the infratemporal fossa (IFT) and parapharyngeal space (PPS). This study further describes the 3-dimensional endoscopic anatomy relevant for exploring the IFT and PPS via the paramandibular window. We also report our expanding clinical experience with this approach.

Methods: One cadaveric specimen injected with colored latex was scanned for stereotactic navigation. The transvestibular approach was used to access the IFT and PPS on both sides using a hand-held 4-mm rigid endoscope, as well as the 5-mm endoscope from the Da Vinci robotic system. A second cadaveric specimen was studied with open dissection and the anatomic course of the carotid artery, and its spatial relationship to key anatomic structure was compared with that of the endoscopic approach. The bony landmarks and muscular, neural, and vascular structures of the IFT and their spatial relationship were digitally captured. Six clinical cases studied involved the resection of juvenile angiofibroma, pleomorphic adenoma, synovial chondromatosis, and a mucoepidermoid tumor.

Results: The transvestibular paramandibular window provided an adequate endoscopic access for exploration of the IFT from the middle cranial base to the upper parapharyngeal space. The medial and lateral pterygoid muscles were useful and reliable surgical landmarks for the endoscopic navigation of this corridor. Benign tumors in the IFT and upper parapharyngeal space, including highly vascular lesions, were safely removed through this approach. Vascular control was achieved in all cases with conventional endoscopic techniques.

Conclusion: The endoscopic paramandibular widow offers a direct minimally invasive approach to the IFT and upper PPS for the management of select lesions. A thorough understanding of the 3-dimensional endoscopic anatomy of this corridor is necessary for the clinical application and expansion of this new approach.