In this study, we discuss the indications for surgery for unruptured cerebral aneurysm and the role of Japan, with special reference to the features of the Japanese medical system based on the data of ruptured cerebral aneurysm. We investigated 506 clipping cases of cerebral aneurysms from 1999 to 2011 in Shimane Prefectural Central Hospital: 182 unruptured cerebral aneurysms and 324 ruptured cerebral aneurysms.
There were four cases (2.2%) of postoperative major complications of unruptured cerebral aneurysm, including two hemiparesis of symptomatic internal carotid artery aneurysm and two visual disturbance of paraclinoid aneurysms. There were two minor complications of transient memory disturbance and two complications of olfactory disturbance of anterior communicating artery aneurysms. There were 13 (7.1%) transient neurological deficits. Postoperative parenchymal abnormality on CT and/or MRI was seen in 14 (7.7%).
Data show ruptured aneurysms occur most frequently in males in their 50’s and in females in their 70’s. The mean size of ruptured cerebral aneurysm according to site was 7±3.4 mm, 6.9±4.0 mm, and 5.7±2.5 mm in internal carotid artery posterior communicating artery aneurysms, middle cerebral artery aneurysms and anterior communicating artery aneurysms, respectively. Small aneurysms under 5 mm were 101 (31.1%).
According to the OECD health data, Japan had the most acute care beds per 1,000 population and the most CT scan and Magnetic Resonance Imaging Units per million population.
The treatment indication of unruptured cerebral aneurysm should be considered more precisely based on sex, age and site. In Japan, we have the most follow-up data on unruptured cerebral aneurysms and should share that data with the world.