左下肺静脈経由の左房内浸潤(T4)肺癌に対し胸部正中切開および体外循環・心停止下に左肺全摘・左房再建を行った1治験例

Left Lung Resection and Left Atrial Reconstruction for Squamous Cell Carcinoma of the Lower Lobe of the Left Lung Performed under Extracorporeal Circulation with Cardiac Arrest Via Median Sternotomy

要旨　左肺癌が経静脈的に左房内浸潤した場合，正中切開による体外循環を用いたアプローチでは，左肺静脈が心臓の背側に当たり，切除・再建が難しい．今回われわれは胸骨正中切開のみにより，体外循環，心停止を行い，左肺全摘と左房下壁側壁の切除，再建を行った症例を経験したので報告する．症例は咳嗽を主訴とする44歳男性．左房内浸潤する左下葉発生の扁平上皮癌と診断された．PETでほかに転移なく，頭部MRIでは微小多発脳梗塞が指摘された．脳梗塞再発や血行性転移の危険性から，手術となった．手術においては胸骨正中切開後に，左内胸動脈剥離用の牽引型開胸器で左胸腔を展開した．上行大動脈送血，右房脱血により体外循環を確立し，大動脈遮断による心停止下に心臓の十分な牽引・脱転を行った．左肺全摘と，左房切除部からの内縫いにより視野の悪い左側左房壁の再建を行った．患者は，術後20日で独歩退院し，1年後も再発の兆候なく良好な経過をたどっている．

　Reconstruction of the left atrium invaded by a left lung cancer performed under extracorporeal circulation with cardiac arrest through median sternotomy is difficult. Compared to median sternotomy, left thoracotomy provides a better view of the left pulmonary veins;however, median sternotomy is sometimes necessary to establish a successful cardiopulmonary bypass and to avoid an air embolism resulting from the hyperextension of the heart while opening the left atrium. We report the case of a 44-year-old man with the diagnosis of left lung squamous cell carcinoma invading the left atrium. Magnetic resonance imaging showed multiple small cerebral infarctions, despite the patient undergoing induction chemotherapy for this cT4N0M0 cancer prior to surgery. Left lung resection and patch reconstruction of the left atrium were performed under extracorporeal circulation with cardiac arrest via median sternotomy. At first, a wound retractor for harvesting the left internal thoracic artery was used to open left thoracic cavity widely and the heart was decompressed under cardiopulmonary bypass. After aortic cross clamp and cardiac arrest, the heart was elevated for observing the left pulmonary veins and cutting the left atrial wall. Then, the left atrial suture line overhanging the left ventricle was observed from inside the left atrium. Thus, left atrial reconstruction was successfully performed. The patient was discharged on postoperative day 20, and showed no recurrence at the 1-year follow-up.