Deep Fenestration of Craniopharyngioma Cysts Does Not Alter Recurrence Risk After Resection: A Single Institution Cohort Study

Introduction: In patients with craniopharyngioma (CP), cyst fenestration is often performed during surgery. Whether or not piercing the cyst through both the near and far walls into a CSF space (deep fenestration) affects recurrence is unknown. Objective: To assess the association between deep fenestration and recurrence, stratified by extent of resection (EOR). Methods: We retrospectively identified 80 patients who underwent surgery for craniopharyngioma at our institution between 1/1/2015 and 1/1/2025. “Deep fenestration” was defined as creation of a communication through both cyst walls. “No deep fenestration” included punctures or single wall openings. Patients were stratified by EOR into gross total and near total resection (GTR and NTR; n=40) and subtotal resection (STR; n=40). Primary outcomes were recurrence and time to recurrence (TTR). Group comparisons were performed two-sample tests selected based on normality and equal variance. Progression free survival (PFS) was calculated with Kaplan–Meier and compared with log rank testing. Results: In the GTR cohort, deep fenestration (n=12) vs. no deep fenestration (n=28) showed similar recurrence rates of 33.3% vs 42.9%, respectively (p=0.573). Among those who recurred, median TTR was shorter after deep fenestration (median: 99 days) than without deep fenestration (median: 494.5 days) (p=0.067). In the STR cohort, deep fenestration (n=11) vs. no deep fenestration (n=29) also showed similar recurrence rates of 63.6% vs 55.2%, respectively (p=0.485). The median TTR in the STR cohort was 164 days for the deep fenestration group and 104.5 for the no deep fenestration group. Kaplan-Meier PFS curves showed no significant difference between deep and no deep fenestration in either the GTR/NTR (p=0.126) or STR (p=0.602) comparisons ([ Figs. 1 ] and [ 2 ]). Conclusion: Deep fenestration of CP cysts was not associated with lower recurrence in either EOR subgroup. Overall, this data suggests that deep fenestration should not be assumed to mitigate recurrence risk. As a result, its value can be perceived as decompressive rather than disease modifying. Validation of these results in larger, multi-institutional cohorts will be important to further define its clinical utility. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany