Quantification Analysis of Minimally Invasive Techniques to the Infratemporal Fossa

Introduction: The infratemporal fossa has always been an anatomically challenging location with several neurovascular elements, The maxillary artery and its branches as well as its close proximity to trigeminal ganglion and its branches and connections to the orbit via the inferior orbital fissure, pterygopalatine fossa, and the nose. Lesions and tumors of the infratemporal fossa have been either arising from these structures or extending into it through fissures from the nose or the orbit.

Aim of Work: In this study, comparison of transnasal transmaxillary, as well as the endoscopic transorbital approach, will be conducted to find out the best suitable approach for lesions in each quadrant of the four quadrants of the infratemporal fossa. Four cadaveric heads were used, both sides right and left. Endoscopic endonasal approach with maximal exposure possible was performed associated with medial maxillectomy to be able to reach as lateral as possible. A transmaxillary approach was done, an endoscopic transorbital approach was performed to dissect the infratemporal fossa and expose the parapharyngeal fascia. Using the navigation system, Cartesian coordinates were collected via Stryker navigation system in Altvision laboratory, and the surgical freedom area of exposure and angle of attack were calculated.

Fig. 1 A panoramic view of the infratemporal fossa through a transorbital approach. Five anatomical points were chosen to compare between the three approaches regarding surgical freedom and area of exposure and angle of attack. Each point would represent a quadrant of the infratemporal fossa and the fifth point is to represent depth while operating. These points are foramen ovale, the TMJ, inferior alveolar foramen, the inferior most portion of the pterygoid process. The fifth point is the point of intersection of the diagonals of the rectangle created by these points.

Fig. 2 Showing the TMJ through—a transorbital view.

Results: Statistical data analysis was performed using a statistical software program (SPSS for Windows, version 21, United States), data were presented as mean with standard deviation. To compare the used approaches (transorbital transmaxillary and transnasal) One-Way ANOVA test was conducted. If there is a statistically significant difference between the used methods, Tukey's multiple comparison posthoc test was done to know which of the specific groups differed. Inf alveolar foramen was not reachable through transnasal method, so in such case, paired t-test was conducted to compare between the two used methods; transorbital and transnasal. For all statistical analysis, results were considered significant at p < 0.05.