Evaluating endoscopic and endoscopic-assisted access to the infratemporal fossa: a novel method for assessment and comparison of approaches

Objectives/hypothesis: Endoscopic infratemporal fossa (ITF) surgery is a growing clinical interest. This study presents a method of analyzing approach access and visualization, identifies relevant anatomy in an endoscopic approach to the ITF, and compares endoscopic medial maxillectomy (MMA) and endoscopic-assisted sublabial transmaxillary (SLT) approaches to the ITF as a model for this paradigm.

Study design: Human cadaver anatomic study.

Methods: Five human cadaver heads (10 ITF dissections) were used. An SLT and MMA were performed on each side. For endoscopic dissections of the ITF, 0° and 30° endoscopes were used. Key landmarks were the posterior maxillary sinus wall, temporomandibular joint, pterygoid plates, foramen spinosum, and foramen ovale. Open dissection was used to confirm ITF landmarks. A novel measurement method using angles of approach and visualization was used to compare approaches.

Results: Visualization and mobility in SLT and MMA were significantly different. The lateral extent and greatest average depth for dissection was 7.9 cm in MMA and 6.1 cm for SLT. The average angle of mobility in approach was 36.3° for MMA and 57.9° for SLT. Average visualization was 40.2° for MMA and 126.5° for SLT. Despite these differences, both surgical approaches allowed access and visualization to all targeted landmarks.

Conclusions: This evaluation paradigm provides useful data in evaluating an endoscopic or endoscopic-assisted approach to the ITF. Using this paradigm, the SLT and MMA were analyzed. Each provided adequate access to the ITF, but visualization and maneuverability were better in SLT.