Abstract
BACKGROUND
Delayed optic neuropathy after flow diversion for paraclinoid internal carotid artery (ICA) aneurysms has mainly been reported in patients with preoperative mass effect; risk in asymptomatic, electively treated patients is unclear. The authors report transient, steroid-responsive optic neuritis after Pipeline Shield placement with coiling for an asymptomatic paraclinoid aneurysm.
OBSERVATIONS
A woman in her 50s underwent elective flow diversion for a growing, asymptomatic left paraclinoid ICA aneurysm (10.4 mm). A Pipeline Shield and two coils were deployed uneventfully; she was discharged on day 5. On day 10, she developed progressive vision loss. Fundoscopy was normal, but critical flicker frequency (CFF) was reduced and a paracentral scotoma was present, indicating retrobulbar optic neuropathy. MRI showed a doughnut sign without aneurysm enlargement, distinguishing inflammatory from compressive or ischemic mechanisms. Corticosteroid therapy produced complete recovery within 1 month, with CFF normalization.
LESSONS
Delayed optic neuritis can follow flow diversion in preoperatively asymptomatic patients; proximity of the optic nerve to the aneurysm, rather than mass effect, confers this risk. A normal fundus, reduced CFF, a scotoma, and a doughnut sign without sac enlargement identify inflammatory optic neuritis and warrant prompt corticosteroid treatment. Elective paraclinoid flow diversion merits counseling and early visual surveillance even when asymptomatic.
https://thejns.org/doi/10.3171/CASE26638