Efficacy and Safety of Optic Nerve Sheath Fenestration for Idiopathic Intracranial Hypertension. A Subgroup-Focused Systematic Review and Meta-Analysis.

Introduction: Optic nerve sheath fenestration (ONSF) is an important surgical management option for idiopathic intracranial hypertension (IIH) who failed medical treatment. We conducted a systematic review and meta-analysis to evaluate the outcomes of ONSF, with a focus to identify factors affecting treatment success. Methods: A literature search was conducted up to December 2024. Primary outcomes included improvement in visual acuity, visual fields, and optic disc swelling resolution. We performed a detailed subgroup analysis based on geographic location, study design, surgical approach, and technical variations. Results: Nineteen studies with a total of 1,159 patients were included in our study. ONSF significantly improved visual acuity in 34.5% (95% CI: 31.8-37.3%) and visual fields in 69.4% (95% CI: 65.9-72.7%) of cases. A 90.9% improvement rate was observed in reducing optic disc swelling. Significant heterogeneity was noted in visual acuity (I Conclusions: ONSF demonstrates favorable efficacy in improving visual outcomes with an acceptable safety profile, lower postoperative complications were observed when the procedure was performed in high-volume centers using appropriate surgical techniques. Geographic variations and surgical approaches significantly affected outcomes, highlighting the importance of standardized protocols and adequate surgical experience. Future prospective studies with standardized outcome measures are needed to optimize patient selection and surgical techniques.