Cranial nerve palsies and intracranial aneurysms: A narrative review of patterns and outcomes

Cranial nerve palsy (CNP) in patients with intracranial aneurysms (IAs) can impose significant burdens on a patient’s quality of life. The literature has a paucity of reviews addressing patterns of overall reported cranial nerve (CN) involvement and outcomes in patients with IA. The literature systematically reviewed CNP at presentation in the setting of IA using PubMed, Web-of-Science, and Scopus according to the PRISMA guidelines. Fifty-two studies reported a total of 513 patients with IA and 630 CNPs observed at presentation: oculomotor (58.25%), abducent (15.87%), optic (12.06%), trochlear (8.7%), and trigeminal (1.9%). Most common aneurysms are located in a posterior communicating artery (46%) and cavernous internal carotid artery (29.2%). Trends of CNP based on the rupture status of IAs showed that 80% were associated with unruptured IAs and 20% with ruptured IAs. Post-treatment of IA, 55% of patients had complete resolution of CNP, with most (89%; n = 134) resolving within the first 6 months. Stratified by CNP type: Complete resolution rate is 100% in CN VII–IX, 60% in CN VI, 59% in CN IV, 54% in CN III, 45% in CN V, and 43% in CN II. In patients with cranial nerve palsies attributed to IAs, the location and rupture status of the aneurysm could determine the type and severity of the nerve palsy. Most patients experienced favorable outcomes in terms of their resolution and long-term function of the CNP after treatment of the IA.