中大脳動脈に生じたlarge kissing aneurysms―症例報告および文献的考察（発生部位による分類）

Large Kissing Aneurysms of The Middle Cerebral Artery : A Case Report －Classification of Kissing Aneurysms－

　Ⅰ．はじめに

2個の脳動脈瘤が相接して生じた場合，kissing aneurysmsと呼ばれるが，これは比較的稀な病態である．1978年にJefferson⁵⁾によって初めて報告され，現在までに22例^1-12)の報告がある．

　今回，われわれは，脳内血腫を伴ったくも膜下出血で発症した中大脳動脈（MCA）部のkissing aneurysms例を経験した．これまで，MCAに生じたkissing aneurysmsの報告例はなく，診断，手術手技上において，このような病態を認識することが重要であると考え，文献的考察を加えて報告する．さらに，これらの動脈瘤のクリッピングがどのような点で困難であるのかを明確にするため，過去の報告を相互の動脈瘤の頸部の位置関係に注目して2群に分類した．

　We report a rare case of kissing aneurysms located at the middle cerebral artery. A 69-year-old man had a severe subarachnoid hemorrhage associated with intracerebral hematoma (Hunt and Hess grade 5,WFNS grade V). Angiography revealed two large-sized aneurysms of the middle cerebral artery,and these aneurysms were seen as contact-ing each other. Both aneurysms were adherent,with fibrous tissue at each dome site. Neck clipping was performed.

　The difficulty of neck clipping with kissing aneurysms is dependent upon the relationship between the two aneurysmal necks. We classify kissing aneurysms into two groups based on the location of the aneurysmal neck (Type 1: each aneurysmal neck is located on the same parent artery. Type 2: each aneurysmal neck is located on different parent arteries.). In Type 1,preoperative diagnosis of kissing aneurysms is difficult and premature rupture during the application of a clip occurs frequently. Therefore,careful and meticulous dissection between the aneurysms is especially required. On the other hand,with Type 2 cases,large aneurysms (＞15mm) are seen much more frequently than in cases of Type 1. Our classification of kissing aneurysms is useful to assess the difficulty of neck clipping for these aneurysms.