504 Anterior-posterior Diameter Is a Key Driver of Resectability and Complications for Pituitary Adenomas With Suprasellar Extension in Endoscopic Transsphenoidal Surgery

Abstract

INTRODUCTION: As endoscopic transsphenoidal approaches are more routinely selected for larger pituitary adenomas with parasellar extension, understanding potential anatomical factors that limit resection and contribute to complications becomes increasingly important. METHODS: A single-center retrospective review of all endoscopic transsphenoidal surgeries for pituitary adenomas with suprasellar extension from 2015-2020 was performed. Preoperative MRIs were systematically assessed to assign a Knosp classification, a Zurich Pituitary Score (ZPS), and to measure lesional suprasellar dimensions. Univariate comparisons and multivariate regression models were employed to assess the influence of these factors on extent of resection (EOR) and postoperative complications. RESULTS: Of the 96 patients with suprasellar pituitary adenomas who underwent endoscopic transsphenoidal surgery, 74 patients (77%) had a gross total resection (GTR). Neither Knosp grade nor ZPS were associated with GTR (Knosp 3A-4 versus Knosp 0-2, p = 0.069; ZPS III-IV versus ZPS I-II, p = 0.079). Multivariate regression identified suprasellar anterior-posterior tumor diameter (SSAP) as the only significant predictor of EOR (OR 0.951, 95% CI 0.905-1.000, p = 0.048*). Higher SSAP also showed the strongest association with an increased overall complication rate (p = 0.0003*) and intraoperative CSF leaks (p = 0.0012*). Further analysis of the regression model for GTR suggested an optimal cut point value for SSAP of 23.7 mm, above which predictability for failing to achieve GTR carried a sensitivity of 89% and specificity of 41%. CONCLUSIONS: This study is unique in its examination of endoscopic transsphenoidal surgical outcomes for pituitary adenomas with suprasellar extension. Our findings suggest that previously established grading systems based on lateral extension into the cavernous sinus lose their predictive value in lesions with suprasellar extension and, more specifically, with increasing suprasellar anterior-posterior diameter.