Effectiveness of optic nerve sheath fenestration in preserving vision in idiopathic intracranial hypertension: an updated meta-analysis and systematic review

Background: This study aims to evaluate the effectiveness of Optic Nerve Sheath Fenestration (ONSF) in improving visual outcomes in patients with Idiopathic Intracranial Hypertension (IIH).

Methods: A meta-analysis was conducted using data from 19 studies, totaling 1159 observations. The main assessed outcomes after ONSF surgery were: the improvement in visual acuity, the improvement in visual fields and reduction in papilledema. We performed separate analyses to distinguish between outcomes using different surgical approaches. Comprehensive literature searches were conducted in the Ovid MEDLINE(R) and SCOPUS databases, following PRISMA guidelines. Statistical analyses employed a Generalized Linear Mixed Model (GLMM) to integrate proportion data, with heterogeneity assessed via I-squared and H statistics. Publication bias was evaluated using funnel plots, Egger's test, and Peters' test.

Results: The analysis revealed that ONSF significantly improved visual acuity in 41.09% of patients, and visual fields in 76.34% of cases. The transconjunctival approach demonstrated higher success rates for visual field improvement. A high improvement rate of 97% was observed in reducing optic disc swelling. Significant heterogeneity was noted, particularly in visual acuity (I² = 92.1%) and visual field improvements (I² = 73.8%), reflecting variability in surgical techniques and patient demographics. Publication bias assessments indicated no significant bias for visual acuity and visual field outcomes, although potential bias was detected for papilledema reduction.

Conclusions: This meta-analysis confirms that ONSF is effective in improving visual outcomes for IIH patients, especially when using the transconjunctival approach. Early surgical intervention is crucial for optimal results, principally in preventing advanced ischemic damage. Despite high success rates, observed heterogeneity highlights the need for standardized surgical techniques and further investigation into patient-specific factors influencing outcomes. Addressing potential publication bias and conducting more rigorous studies will enhance the reliability of future meta-analyses. Upcoming research in ONSF efficacy is needed to refine surgical practices and optimize patient care.