重複下大静脈を伴う直腸癌に対してロボット支援下手術を施行した1例

A case of robot-assisted anterior resection for rectal cancer with double inferior vena cava

◆要旨：症例は67歳の女性で，血便を主訴に近医を受診した．下部消化管内視鏡検査で直腸S状部に2型腫瘍を指摘され，病理検査結果でGroup5と診断されたため，手術加療目的に当科を受診した．術前の造影CT検査では直腸S状部に全周性の壁肥厚と周囲リンパ節腫大を認めたが，遠隔転移を疑う所見は認めなかった．また，重複下大静脈を認めた．直腸S状部癌，cT2N1bM0，cStage Ⅲaと診断し，ロボット支援下直腸高位前方切除術，D3郭清を施行した．術中所見では下腸間膜動脈切離後，左側結腸間膜の内側授動の際に，尿管および左卵巣動静脈とともに左側下大静脈を確認して温存し，特に合併症なく定型的に手術を施行した．術後経過は良好であり，術後11日目に退院となった．

　A 67-year-old woman consulted her previous doctor with a chief complaint of bloody stool. She was diagnosed with rectal cancer and referred to our department for surgical treatment. Computed tomography revealed concentric thickness of the rectosigmoid wall and the double inferior vena cava. The tumor was diagnosed as rectal cancer cT2N1bM0 cStageⅢa, and robot-assisted anterior resection was performed. We identified the double inferior vena cava during surgery. There were no massive bleeding necessitating blood transfusion or complications. Double inferior vena cava is a congenital venous anomaly with a reported incidence of 1.0％-3.0％. Most cases of double inferior vena cava are clinically silent and diagnosed incidentally. However, such venous anomalies can cause massive bleeding during abdominal surgery. The precise recognition of such anatomies is important to avoid fatal complications during surgery.