Improvement in cranial nerve palsies following treatment of intracranial aneurysms with flow diverters: Institutional outcomes, systematic review and study-level meta-analysis.

Background: Cranial nerve (CN) palsies are rare presenting symptoms of intracranial aneurysms. Our objectives were to report our institutional outcomes and study-level meta-analysis summarizing rates of improvement and identifying factors associated with recovery from CN symptoms after flow diversion.

Methods: We conducted a retrospective review of our institutional database for patients with intracranial aneurysms presenting with CN palsies who underwent treatment with flow diversion between 2015 and 2023. Systematic review of the literature was performed using Medline, EMBASE, Cochrane, as well as manual citation searches. Random effects meta-analysis was used.

Results: Thirteen of 136 studies were included in the meta-analysis and were combined with our institutional data. The pooled rate of improvement in any CN palsies following flow diversion was 71 % (95 %CI, 60 %-82 %, n=322). Patients presenting with CN II deficits were less likely to improve following treatment compared to other CN deficits (pooled OR [pOR] 0.32, 95 %CI, 0.16-0.63, n=224). The pooled rate of clinical improvement was 53 % in CNII deficits (95 %CI, 42 %-65 %, n=80) and 80 % in other CN deficits (95 %CI, 71 %-88 %, n=106). An increased rate of improvement was associated with acute intervention (pOR 9.12, 95 % CI, 2.26-36.73, n = 71) and radiographic aneurysm occlusion (pOR 5.29, 95 %CI, 1.66-16.90, n=118).

Conclusions: Flow diversion improves CN palsy outcomes in patients with symptomatic intracranial aneurysms. The lower rate of improvement in visual acuity compared to other CN deficits may point to a different mechanism of injury or potential recoverability in these patients.