胸腔鏡下縦隔・胸壁腫瘍手術

Video-assisted Thoracoscopic Surgery for Mediastinal Tumor and Thoracic Wall Tumor

縦隔腫瘍はCTの高性能化により10 mm以下の腫瘍も画像上で指摘されるようになっている．さらに縦隔腫瘍は術前診断が困難であり，基本的には切除となる．また，胸腺腫は2015年の世界保健機関（WHO）分類の改定作業1）を受けてInternational Classification of Diseases for Oncology（ICD-O）における胸腺腫コードの5桁目が1から3へ変更され，悪性腫瘍として位置づけられている．しかし成人の前縦隔は胸腺の脂肪化した組織に埋め尽くされ，10 mm程度の腫瘍を胸腔鏡下で確認する作業は困難であることが多い．さらに，胸腺静脈が比較的太く短いという解剖学的特徴も存在する．

“A final conceptual change concerns the appreciation that all major thymoma subtypes can behave in a clinically aggressive fashion and, therefore, should no longer be called benign tumors, irrespective tumor stage. Accordingly, their International Classification of Disease for Oncology （ICD）-O codes now have a /3 suffix, thymomas, for as malignant.1）” This manuscript indicated that almost all mediastinal tumors, which could not be easy to diagnose per-operatively, should be removed. There were two large problems for mediastinal tumors resection with video-assisted thoracoscopic surgery （VATS）. First is management or approach for the thymic vein, which have a short distance but large diameter relatively, and individual variation about the position and the number. Some solutions were 1） performance of pre-operative enhanced computed tomograpy （CT） or magnetic resonance imaging （MRI）, 2） transcervical approach with Kent retractor, 3） sternal-L shape approach. Second is for the patients, which have thymoma or thymic tumor with myasthenia gravis, to what extent should be removed anterior fatty tissue. For the moment including beneath the innominate vein it should be removed as extent as possible. Liga Sure Impact was useful to remove a large thoracic wall tumor with VATS for resection of thick muscle.