Aneurysms of the posterior communicating artery and oculomotor paresis.

One hundred and seventy-four patients with a posterior communicating aneurysm were seen over a 21 year period. There was a ratio of four females to one male and women were on average five years older. Fifty-nine (34%) had an oculomotor paresis. This group had up to four attacks of localized headache, large multiloculated aneurysms, and a greater time lapse from the onset of symptoms to surgery compared with those patients without oculomotor palsy. Delay in treatment allowed further attacks to occur which increased the mortality rate and decreased the chance that the eye would recover. Eighteen people who had had a palsy before craniotomy two to 18 years previously were examined. In four (22%) the paralysis had recovered completely, 14 (78%) had greatly reduced oculomotor function, and nine (50%) showed aberrant regeneration of the nerve. Nine of 62 patients, seven of whom were seen, developed a palsy after craniotomy and in five the eye had returned to normal.