Anteroposterior suprasellar diameter as a predictor of gross total resection in pituitary adenomas with suprasellar extension: A retrospective cohort study

Background: Pituitary adenomas (PAs) with suprasellar extension pose significant surgical challenges due to restricted access and a heightened risk of subtotal resection (STR). To test this hypothesis, we evaluated suprasellar morphometrics focusing on anteroposterior suprasellar diameter(APSS) as predictors of gross total resection (GTR) in PAs with suprasellar extension, while accounting for parasellar invasion using established cavernous sinus scales (Knosp and Zurich pituitary score [ZPS]). Methods: A retrospective cohort of 48 consecutive patients who underwent endoscopic endonasal surgery for PAs with suprasellar extension between July 2021 and June 2024 was analyzed. Demographic, radiologic, and intraoperative variables were collected. The extent of resection was determined by early postoperative magnetic resonance imaging. Logistic regression and receiver operating characteristic (ROC) curve analysis were used to identify predictors of GTR. Results: The mean patient age was 52.2 ± 11.6 years, with a male-to-female ratio of 1.1:1. Most tumors were nonfunctioning (81.3%). GTR was achieved in 70.8% of cases. Postoperative complications occurred in 27.1%, including cerebrospinal fluid leaks in 16.7%, one postoperative hematoma (2.1%), and two deaths (4.2%). Neither Knosp nor ZPS classifications showed significant correlation with GTR ( P = 0.055 and P = 0.258, respectively). Logistic regression identified APSS as an independent predictor of resectability ( P = 0.023). ROC analysis established an optimal APSS cutoff of 25.7 mm, with 78% sensitivity and 88% specificity for predicting STR. Knosp and ZPS are designed to quantify cavernous sinus invasion; in our suprasellar-extension cohort, their association with GTR did not reach statistical significance, whereas APSS capturing sagittal suprasellar depth beyond the endonasal working angle remained an independent predictor of incomplete resection. Conclusion: The APSS is an independent and reliable morphometric predictor of surgical outcome in PAs with suprasellar extension. An APSS ≥25.7 mm is associated with an increased risk of incomplete resection and may outperform conventional grading systems in preoperative planning.