Oculomotor nerve palsy by non-aneurysm vascular compression (P5.186)

Objective: Case report of oculomotor nerve palsy by non-aneurysm vascular compression Background: Non-aneurysmal vascular compression of oculomotor nerve causing neurologic symptom is rare. We report a case of complete oculomotor nerve palsy by non-aneurysmal posterior communicating artery, which was treated by microvascular decompression. Design/Methods: A 74-year-old woman came to the hospital complaining of ptosis and diplopia in July, 2015. Medical history included hypertension. On neurologic examination, she had left oculomotor nerve palsy, with left pupil dilated to 6mm, unresponsive to light. High-resolution magnetic resonance imaging revealed left posterior communicating artery compressing left oculomotor nerve. Craniotomy was performed to find that sagging posterior communicating artery compressed left oculomotor nerve, and the nerve showed color change which means degenerative change had occurred. Polytetrafluoroethylene was applied to relieve pressure on the left oculomotor nerve. The patient’s oculomotor nerve palsy disappeared completely one month after the surgery. Results: Vascular compression to the oculomotor nerve has been reported frequently in asymptomatic individuals. Therefore, it may be controversial to say that non-aneurysmal vascular compression of oculomotor nerve is a true reason for oculomotor nerve palsy in symptomatic patients. There were 13 case reports describing non-aneurysmal vascular compression of oculomotor nerve causing oculomotor nerve palsy. Among them, 6 cases including this case performed decompression surgery and neurologic deficit improved after 1month to 1 year from the surgery. In the past, computed tomography or conventional angiography could not detect spatial relationship between oculomotor nerve and vessels. Technical development in magnetic resonance image(MRI) modality revealed non-aneurysmal vascular compression of oculomotor nerve. Because ptosis and diplopia undermine patient’s daily life, microvascular decompression surgery should be considered in patients with symptomatic oculomotor nerve palsy by non-aneurysmal vascular compression. Conclusions: It is important to consider non-aneurysmal vascular compression as a cause oculomotor nerve palsy, and microvascular decompression surgery should be considered. Disclosure: Dr. Jo has nothing to disclose. Dr. Lim has nothing to disclose. Dr. Kim has nothing to disclose. Dr. Kim has nothing to disclose.