Present Situation of Therapy for Cerebral Aneurysm in Japan: According to the Data of Our Institute, the Japan Standard Stroke Registry Study, and the Japan Neurosurgical Society

Abstract

The incidences of subarachnoid hemorrhage (SAH) in Finland and Japan are the highest in the world, with about 20-23 cases per 100,000 persons per year. Since the report of the International Subarachnoid Aneurysm Trial (ISAT) was published, the use of intravascular coil embolization (CE) for cerebral aneurysm has become more frequent worldwide. In this paper, we discuss the current situation of therapy for cerebral aneurysm in Japan according to the data of our institute, the Japan Standard Stroke Registry Study, and the Japan Neurosurgical Society. From 1999 to 2013, 543 cases of ruptured saccular cerebral aneurysms were treated in Shimane Pre-fectural Central Hospital. According to data, most cases occurred in men in their fifties and in women in their seventies. The mean sizes of ruptured cerebral aneurysm according to site were 7.4 ± 4.1, 7.0 ± 5.4, and 5.5 ± 2.5 mm in the internal carotid artery posterior communicating artery, middle cere-bral artery, and anterior communicating artery, respectively. Aneurysms smaller than 5 mm account for 187 (34.4%) of the cases. According to the Japan Standard Stroke Registry Study, the poor outcome rates (modified Rankin scale score, 3-6) according to the ISAT criteria were 18.3% and 24.2% in the surgical clipping (SC) and CE groups, respectively. These rates were superior to the ISAT data (36.4% for SC and 25.4% for EC). According to the survey of the Japan Neurosurgical Society from 2001 to 2011, the prevalence of cere-bral aneurysm cases treated with clipping decreased from 88.2% in 2001 to 71.2% in 2011. The number of ruptured cerebral aneurysms treated with clipping also decreased. However, the frequency of clipping for unruptured cerebral aneurysm was increasing.