Dolichoectatic basilar aneurysmの自然予後および現在の治療状況 : アンケート調査の分析 : 椎骨脳底動脈thrombosed aneurysmの病態と治療  [in Japanese] Natural History of Dolichoectatic Basilar Artery Aneurysm: Analysis of Questionnaire  [in Japanese]

dolichoectatic aneurysmは, 伸展(elongation)曲折(tortuosity)し, 拡張(ectasia)した動脈に生じた巨大紡錘状動脈瘤(giant fusiform aneurysm)と定義される. 一般に巨大脳動脈瘤の発生頻度は5-7%であり, 巨大紡錘状動脈瘤の発生頻度は全脳動脈瘤の0.1-0.7%を占めると考えられる. そして巨大紡錘状動脈瘤の70%が後頭蓋窩に発生し, 特に椎骨動脈に好発する. この巨大紡錘状動脈瘤が脳底動脈に発生した症例が, dolichoectatic basilar aneurysmであるが, きわめてまれな病態のためその自然歴は十分に解明されていない. また脳底動脈本幹そのものが動脈瘤化しているため, その外科的治療方法は脳外科医にとってチャレンジングなものであり, 現在脳外科領域で手治療方法の確立していない疾患のひとつである. 今回dolichoectatic basilar aneurysmの自然歴, 現状での治療方法および治療成績を明らかにするため, 本邦A項病院にアンケート調査を行ったのでその結果について報告する.

We conducted a questionnaire survey of A-class neurosurgical institutes in Japan to elucidate the natural history of dolichoectatic basilar artery aneurysm. Thirty out of 316 A-class institutes answered the questionnaire, 22 of which experienced the treatment of dolichoectatic basilar artery aneurysm. Fifty-two patients treated in 22 institutes during 1991 and 2001 were analyzed: 42 males with a mean age 59 and 10 females with a mean age 54. They presented with mass effect; 48%, ischemia; 19%, hemorrhage; 18% at initial diagnosis. Examination of vertebral artery angiography revealed asymmetric vertebral arteries in 82% of them and aneurysm lesion involving both the basilar and vertebral artery in 52%. Thirty of the 52 patients were treated medically and the other 22 were treated surgically. In the medically treated group only 5 patients were unchanged during follow-up period, while 25 patients other worsened and 84% eventually died within 3.6 years. The causes of death were repeated hemorrhage (67%) and growing aneurysm lesion (20%). Nine patients developed hydrocephalus requiring a ventriculo-peritoneal shunt, and 4 patients developed dementia. Surgery was performed in 22 cases 1.6 years after the initial symptom on average. Two patients who suffered from subarachnoid hemorrhage underwent surgery in the acute phase. The other 20 patients, who showed progressive deterioration due to growing mass effect and repeated hemorrhages, were treated with parent artery ligation and high-flow bypass using radial artery graft. Fifty percent of surgical cases recovered to social activity or survived without any aid in their home, but the other 50% had poor results, including 25% who died. This study shows that the natural history of dolichoectatic basilar artery aneurysm is very poor and almost 70% died within 3 years. Another 20% became bed-ridden because of their diseases.