Endoscopic endonasal approach to the maxillary strut: anatomical review and case series.

Objectives/hypothesis: The maxillary strut is the bone that separates the foramen rotundum and superior orbital fissure. Tumors involving the lateral wall of the sphenoid sinus, posterior ethmoid, or posterior maxillary sinus may invade this region. The authors detail the anatomy of the strut and present a case series that emphasizes the importance and utility of this useful landmark during an endoscopic endonasal approach to lesions in this region.

Study Design: Cadaveric dissections and retrospective case series.

Methods: Endoscopic endonasal dissections were performed on six formalin-fixed cadaver heads. Morphometric analyses of 100 skulls were conducted using CT scans and BrainLab. Four patients underwent procedures that exposed the maxillary strut.

Results: The maxillary strut was trapezoidal shaped with an average cross-sectional area of 15.25 ± 0.48 mm(2) and average thickness of 4.43 ± 0.10 mm. The maxillary strut was present bilaterally in all skulls examined. Anteroposterior length averaged 4.18 ± 0.15 mm on the right and 3.90 ± 0.14 mm on the left. Our patient series illustrated the clinical utility of the maxillary strut as a landmark during endoscopic approaches to the skull base.

Conclusions: An endoscopic endonasal approach can be used to expose the maxillary strut. Improved understanding of this anatomy is important to achieving success when using this approach for the biopsy or resection of lesions in the lateral sellar compartment, pterygopalatine fossa, and aspects of the middle cranial fossa.