Third nerve palsy following carotid artery dissection and posterior cerebral artery thrombectomy: Case report and review of the literature

Background: Common causes of oculomotor nerve palsy are diabetes, aneurysmal compression, and uncal herniation. A lesser-known cause of third nerve dysfunction is ischemia, often due to carotid artery dissection. Case Description: An 80-year-old man presented with an acute ischemic stroke with a National Institutes of Health Stroke Scale score of >20 from a high cervical internal carotid artery (ICA) dissection and a tandem ICA terminus embolic occlusion with extension of clot into the adjacent fetal posterior cerebral artery (PCA). We used a stentriever to perform selective PCA thrombectomy, with immediate postthrombectomy development of ipsilateral anisocoria. The anisocoria progressed into complete oculomotor nerve palsy over 8 h after the procedure. Conclusions: The clinical course described in this case is consistent with injury to the third nerve due to mechanical injury or occlusion of perforator supply to the nerve during thrombectomy. Oculomotor nerve palsy is a rare but known complication after ischemia; however, to our knowledge, this is the first case after thrombectomy for a PCA embolus.