Oculomotor nerve palsy in patients with cerebral aneurysms.
Twenty-six patients with oculomotor nerve palsy due to cerebral aneurysms were examined. There were six males and twenty females with a mean age of 55 years. 25 of the 26 aneurysms were located at the junction of the internal carotid and the posterior communicating artery and one was at the junction of the basilar artery and the superior cerebellar artery. Twelve patients had associated subarachnoid hemorrhage (SAH); the other 14 did not. The initial symptoms in many patients were ptosis and double vision. Twenty-one of the patients had total oculomotor nerve palsy, one had a sparing of medial rectus muscle; three patients had only ptosis and anisocoria, and one had oculomotor nerve palsy with pupillary sparing. All aneurysms, including giant aneurysms, were clipped under a microscope, and six oculomotor nerves were found to be decompressed at surgery. The follow-up periods were from six months to three years. Nine patients had a complete recovery of oculomotor function; thirteen had an incomplete recovery; and four remained unchanged. The mean interval between the onset of palsy and the time of surgery was 24 days in complete recovery cases, 42 days in incomplete recovery cases, and 119 days in unchanged cases. The recovery of oculomotor function started with the levator palpebrae muscle and followed by the medial rectus muscle. The recovery of pupillary function was, however, not consistent. Of the factors influencing recovery from oculomotor nerve palsy, the interval between the onset of palsy and the time of surgery was most important. Therefore, aneurysms with oculomotor nerve palsy should be operated on as early as possible, regardless of the presence or absence of SAH.