Long-term visual outcomes after surgical management for intracranial idiopathic hypertension

Idiopathic intracranial hypertension (IIH) with progressive or vision-threatening disease may require surgical intervention such as optic nerve sheath fenestration (ONSF) or CSF diversion. Venous sinus stent (VSS) placement has emerged as an alternative treatment option in patients with venous sinus stenosis. The authors report their single-center experience with these three modalities, focusing on long-term visual outcomes, treatment durability, and reoperation patterns.

The authors retrospectively reviewed the medical records of all newly diagnosed IIH patients undergoing ONSF, CSF diversion (ventriculoperitoneal shunt insertion), or VSS placement between 2010 and 2024. Demographic, clinical, and neuro-ophthalmological data were collected through last follow-up, including visual acuity, Humphrey visual field (HVF) mean deviation, retinal nerve fiber layer (RNFL) thickness, and Frisén grade. Treatment failure was defined as persistent papilledema, the need for a different surgical modality, or repeat surgery of the same type. Cure was defined as complete papilledema resolution or marked improvement in IIH-related symptoms. Statistical analysis included Kruskal-Wallis, pairwise Wilcoxon, and Fisher's exact tests, with Kaplan-Meier survival analysis for time-to-event outcomes.

Thirty-six patients (mean age 32.3 ± 11.3 years, mean BMI 36.7 ± 8.9 kg/m2) were included; 94.4% presented with optic disc edema and 91.7% with visual deficits. Initial procedures were ONSF (n = 10), shunt insertion (n = 13), and VSS placement (n = 13). Failure occurred most frequently after ONSF (6/10, 60%), followed by VSS insertion (4/13, 30.8%) and shunt placement (4/13, 30.8%) (p = 0.273). Among failures, reoperation with the same modality experienced the highest rate of failure after shunt placement (40%) versus VSS insertion (23.1%) and ONSF (0%) (p = 0.056). Kaplan-Meier analysis showed earlier reoperations after VSS placement, typically acute/subacute, and later mechanical failures after shunt placement. Visual outcomes improved across all modalities. Visual acuity improved by a median of -0.13 logMAR (logarithm of the minimum angle of resolution) overall, with the greatest improvement after ONSF (-0.70 logMAR). HVF sensitivity improved by +4.8 dB, with the largest gains after shunt insertion (+6.2 dB) and ONSF (+5.7 dB). RNFL thickness decreased across groups, consistent with disc swelling resolution. The median time to papilledema resolution was shortest for ONSF (61 days) and shunt placement (88 days) compared with VSS insertion (176.5 days), although this was not statistically significant. Successful ONSF cases often resolved rapidly and completely.

Surgical intervention for IIH achieved high rates of papilledema resolution and visual improvement, with low long-term failure rates. Each modality showed distinct strengths, limitations, and temporal failure patterns. Papilledema resolution and time to resolution may serve as meaningful clinical endpoints in future multicenter IIH studies.