Optic Nerve Sheath Fenestration for Progressive Visual Loss in Cerebral Venous Sinus Thrombosis: A Long-Term Retrospective Observational Study

Introduction Progressive cerebral venous sinus thrombosis (CVST)-induced visual loss remains problematic, despite decreasing overall mortality owing to early diagnosis and aggressive treatment. Optic nerve sheath fenestration (ONSF) improves or stabilizes visual function in patients with idiopathic intracranial hypertension; however, its role in CVST awaits elucidation. We evaluated the efficacy and safety of ONSF in resolving CVST-induced visual impairment based on long-term observation.Methods This observational study included 18 patients with progressive CVST-induced visual loss, who had undergone ONSF between 2012 and 2021. Patients received maximum medical therapy, including anticoagulants and intracranial pressure (ICP)-lowering medications. The best-corrected visual acuity (BCVA), visual fields (VFs), and optic nerve head were assessed at baseline, at 1 week after ONSF, and over 6 months after ONSF. Activities of daily living (ADL) and National Eye Institute Visual Function Questionnaire-25 (VFQ-25) scores were assessed at final follow-up.Results Thirty-one ONSF-treated eyes of 18 patients were included. The mean follow-up duration was 35.6 months (range 1 week-8 years). Two patients were lost to follow-up. Before ONSF, all patients were still experiencing progressive visual loss despite receiving adequate anticoagulation and ICP-lowering therapy. Postoperative BCVA remained stable or improved in 25/31 eyes (80.6%) 1 week postoperatively and 17/28 eyes (60.7%) upon final follow-up. All papilledema resolved postoperatively. No complications were reported except for one transient postoperative diplopia. The median ADL score was 100 (range 25-100), and the mean total VFQ-25 score was 40.6 (range 9.5-87.3).Conclusion This was the largest study to describe ONSF's role in CVST based on a long-term follow-up. Considering its efficacy and favorable safety, ONSF can be considered an important adjunctive approach to resolving progressive visual loss of CVST patients, on the basis of anticoagulation and ICP-lowering therapy.