Intracranial aneurysms and abducent nerve palsy

Abstract

Background: Cranial nerve (CN) palsy may manifest as an initial presentation of intracranial aneurysms or due to the treatment. The literature reveals a paucity of studies addressing the involvement of the 6th CN in the presentation of cerebral aneurysms. Methods: Clinical patient data, aneurysmal characteristics, and CN 6th palsy outcome were retrospectively reviewed and analyzed. Results: Out of 1311 cases analyzed, a total of 12 cases were identified as having CN 6th palsy at the presentation. Eight out of the 12 were found in the unruptured aneurysm in the cavernous segment of the internal carotid artery (ICA). The other four cases of CN 6th palsy were found in association with ruptured aneurysms located exclusively at the posterior inferior cerebellar artery (PICA). For the full functional recovery of the CN 6th palsy, there was 50% documented full recovery in the eight cases of the unruptured cavernous ICA aneurysm. On the other hand, all four patients with ruptured PICA aneurysms have a full recovery of CN 6th palsy. The duration for recovery for CN palsy ranges from 1 to 5 months. Conclusion: The association between intracranial aneurysms and CN 6th palsy at presentation may suggest distinct patterns related to aneurysmal location and size. The abducent nerve palsy can be linked to unruptured cavernous ICA and ruptured PICA aneurysms. The recovery of CN 6th palsy may be influenced by aneurysm size, rupture status, location, and treatment modality.