J Neurosurg. 2025 Dec 5:1-11. doi: 10.3171/2025.8.JNS251211. Online ahead of print.
ABSTRACT
OBJECTIVE: The aim of this study was to evaluate the long-term visual outcomes following optic nerve decompression in patients with CSF flow disturbances and to propose a mechanistic framework for surgical qualification based on infusion testing and orbital MRI, independent of idiopathic intracranial hypertension (IIH) diagnostic criteria.
METHODS: This retrospective study analyzed 30 eyes in 26 patients with progressive visual impairment and evidence of CSF flow abnormalities. All patients underwent standardized lumbar infusion testing to quantify CSF outflow resistance, pressure-volume index, and opening pressure. Orbital MRI was used to assess perioptic CSF collections or optic canal narrowing. On the basis of these data, patients underwent either optic nerve sheath fenestration (ONSF) or endoscopic optic nerve sheath decompression (EONSD). Visual function was evaluated using mean deviation of the visual field, visual evoked potentials, and optical coherence tomography of the retinal nerve fiber layer (RNFL) thickness at baseline and 6 and 24 months.
RESULTS: Mean deviation of the visual field improved by a median of +1.89 dB (p < 0.05), and P100 latency (i.e., the time between a visual stimulus and the visual cortex’s response) decreased by -5 msec at 24 months. Papilledema resolved in 87.5% of affected eyes. RNFL thickness remained stable or modestly increased across the cohort, with a trend toward greater thickening following EONSD (+9 µm at both 6 and 24 months) compared with ONSF (minimal change at 6 months [+1 µm] and slight thinning at 24 months [-2 µm]), although the differences were not statistically significant. No significant differences in functional outcomes were observed between the procedures. Patients were stratified into 3 CSF pathophysiological subgroups: 1) IIH with elevated intracranial pressure (ICP), 2) abnormal hydrodynamics without raised ICP, and 3) normal ICP and hydrodynamics with MRI-confirmed perioptic CSF collection. Visual improvement occurred across all subgroups, including groups 2 and 3.
CONCLUSIONS: The authors found that optic nerve decompression guided by CSF infusion testing and orbital MRI effectively stabilizes or improves visual function in patients with CSF-related optic neuropathy, including those without elevated ICP. A mechanism-based classification into three surgical phenotypes enables individualized treatment beyond syndromic definitions. This approach may redefine surgical eligibility and expand access to vision-preserving interventions in CSF-mediated optic nerve dysfunction.
PMID:41349016 | DOI:10.3171/2025.8.JNS251211
