Morphometric Analysis of the Sphenoid Sinus Ostium in Computed Tomography: Implications for the Endonasal Transsphenoidal Approach in Pituitary Neuroendocrine Tumor Surgery

The sphenoid sinus ostium represents the main anatomical landmark for endoscopic endonasal approaches to the sellar region, which serves as a safe entry corridor into the sphenoid sinus. Characterization of this sinus anatomy is essential for preoperative planning in pituitary neuroendocrine tumor surgery. This study aimed to analyze the morphometric features of the sphenoid sinus ostium to optimize surgical preparation. A retrospective study was conducted on computed tomography scans of 30 control individuals bilaterally (60 sides) and 30 pituitary neuroendocrine tumor patients bilaterally (60 sides). Measurements included distances from the sphenoid sinus ostium to the anterior nasal spine, sphenoid sinus floor, sphenoid sinus ceiling, and anterior sellar wall. Angles between the nasal spine and the ostium to the sellar tuberculum and sellar floor were measured. In the control group, the mean sellar and tubercular angles were 155.5° (SD ± 12.29) and 168.5° (SD ± 9.64) respectively. Longer distances to the sphenoid sinus ceiling correlated with reduced tubercular angles and increased sellar angles, while greater anterior sellar wall distance correlated with larger sellar angles. Pituitary neuroendocrine tumor group displayed a sellar angle of 132.0° (SD ± 15.49) and tubercular angle of 158.7° (SD ± 13.20), both statistically reduced compared to the control group. Sellar and tubercular angles may predict surgical endoscopic trajectory. When these angles are reduced, extensive removal of the posterior ethmoid cells and sphenoid rostrum may be required to adequately expose the tubercular recess and sellar floor, respectively. Preoperative analysis of sphenoid sinus ostium morphometry for surgical planning may guide the extent of bone removal needed, enhancing safety in pituitary neuroendocrine tumor surgery.