Oculomotor Palsy after Flow Diverter Treatment for Paraclinoid Aneurysm: Case Report and Literature Review.

Objective: Flow diverter placement across the ophthalmic artery carries a reported visual-impairment risk of about 1%, yet oculomotor nerve palsy following treatment of small paraclinoid aneurysms without mass effect has not been described. Our objective was to present a case of a transient oculomotor palsy following a flow diverter treatment for 6 and 2.5 mm paraclinoid aneurysms. Case Presentation: A 57-year-old woman underwent flow diverter treatment for two left paraclinoid aneurysms measuring 6 and 2.5 mm. On the fifth post-operative day, she experienced blurred vision, mild left ptosis, and restricted adduction and elevation of the left eye, while pupillary function remained intact. The diagnosis of left pupil-sparing oculomotor palsy was made. Conservative management led to full resolution of symptoms within three months. Follow-up 3D rotational angiography demonstrated occlusion at the origin of the inferolateral trunk of the left internal carotid artery. Conclusion: Oculomotor nerve palsy caused by flow diverter coverage of small internal carotid artery branches supplying the cranial nerves may be an under-recognized complication and warrants clinical attention. A review of the literature suggested an approximately 3% incidence of this complication, and we discussed the pathomechanism of the cranial nerve palsy caused by flow diverter treatment.