Background: Aneurysm of the internal carotid-posterior communicating artery (ICA-PCoA) is the most frequent cause of sudden unilateral oculomotor palsy. Timely surgery for the aneurysm is the most important factor for third nerve recovery.
Methods: We scrutinized the world literature with nearly one thousand cases of isolated unilateral oculomotor palsy caused by intracranial aneurysms and treated with surgery. Only those reports (one-third of all) in which the time interval between onset of oculomotor palsy and surgery could be determined were included. We treated 1314 patients with cerebral aneurysms (183 = 14% with ICA-PCoA aneurysms) from our catchment area in Eastern Finland during years 1977-1992. Twenty-eight patients having oculomotor palsy caused by ICA-PCoA aneurysm had surgery as soon as the diagnosis was made.
Results: Eight of 9 patients operated within three days (0-3) and 4 of 6 patients operated on within 4 to 6 days the onset of oculomotor palsy had complete recovery of their third nerve function, in contrast to only 4 of 13 patients operated on later. Especially those operated on more than four weeks later had a dismal outcome: only 1 of 6 had complete recovery.
Conclusions: We recommend immediate admission and acute or early surgery for aneurysm-induced third nerve palsy, preferably within 3 days, to avoid functionally and cosmetically invalidizing disability.