Trend in Outcome of Cerebral Aneurysmal Rupture Since 1985: A Proposal for Future Treatment

To the Editor: Since 1985, we have been carrying out a population-based study of cerebral aneurysms in the Yamaguchi prefecture of Japan. The population of the area is approximately 1.5 million and has changed little over the last 15 years. The crude annual incidence rate of aneurysmal rupture has gradually increased from 1985 to 1997, from 12.9/100 000 population in 1985 (95% CI, 11.2 to 14.8) to 15.5/100 000 in 1997 (95% CI, 13.5 to 17.8).1 Any patient with cerebral aneurysmal rupture in Yamaguchi was admitted to one of 28 neurosurgical centers, where surgery was performed by well-trained neurosurgeons certified by the Japanese Neurosurgical Society. Our interest has focused on whether the overall management outcome for cerebral …