脳動脈瘤手術中意図的一時血行遮断後脳虚血—多変量解析による危険因子の検討

Multivariate Analysis of Intentional Temporary Vessel Occlusion in Aneurysmal Surgery

I．はじめに

　脳動脈瘤手術中親動脈の一時血行遮断（以下TO：temporary vessel occlusion）は最大径15mm以上の大きな動脈瘤，広頸動脈瘤や困難な部位の動脈瘤クリッピング時には必要な手技の一つである^2）．われわれは脳保護物質を使用下で一時血行遮断時間が延べ40分以上の症例でも神経脱落症状を残さなかった例を経験してきた^8）が，これまで意図的一時血行遮断術後脳虚血の危険因子を検討した報告は少なくTO後脳梗塞を来たす危険因子を知ることは重要である．そこで今回著者らは，自験例において術中意図的にTOを使用した症例について術後の神経脱落症状と転帰に関与した危険因子を多変量解析を用い分析し若干の知見を得たため報告する．

Temporary vessel occlusion (TO) for aneurysmal clipping is an effective technique to facilitate dissec-tion between aneurysm and parent vessels, and to place a permanent clip at the aneurysmal neck precisely.However, several unsolved problems remain regarding the overall safety and risk resulting from this tech-nique. The authors examined a series of patients in whom mannitol 500ml, tocopherol acetate 500mg, andphenytoin 500mg were administered intravenously as ischemic protection during TO for the aneurysmalclipping. The study comprises a nonconcurrent retrospective analysis of 144 consecutive aneurysm clip-pings performed with the aid of intentional TO at the Hiroshima Prefectural Hospital from 1985 to 1995.To identify technical and patient-specific risk factors for perioperative stroke, factors studied includedduration, location of the temporary clip application, number of occlusive episodes, patient sex, age, andpreoperative neurological status, timing of operation, as well as postoperative, temporary or permanent,neurological deficits (ND) due to TO were used. Overall frequency of postoperative ND due to TO man-ifested clinically and radiologically were 9.0% and 9.7%, respectively. In both univariate and multivariateanalysis there were no significant factors relevant to the ND. However, duration of the temporary occlu-sion time over 20 minutes was the factor most influetial on the ND due to TO. Duration of the temporaryocclusion time was shown to have no link with outcome. Based on our findings the authors conclude thattemporary vessel occlusion within 20 minutes with anti-ischemic drugs is a relatively safe adjunct to aneu-rysmal surgery.