左側下大静脈を伴ったS状結腸癌に対して腹腔鏡下S状結腸切除術を行った1例

Laparoscopic sigmoidectomy for sigmoid colon cancer with left inferior vena cava

◆要旨：左側下大静脈は下大静脈の発生過程で生じる血管変異で，腹部大動脈の左側を上行し腎門部レベルで大動脈の腹側を横断する．左側下大静脈はS状結腸間膜の背側を走行するため，S状結腸切除において損傷しないように注意を要する．患者は63歳，女性．腹痛を契機にS状結腸癌と診断された．術前のCT検査で左側下大静脈を認めた．下腹神経前筋膜に沿った剝離層を遵守することで定型通り腹腔鏡下S状結腸切除術を施行しえた．本症例のような脈管変異を伴う症例であっても，術前画像検査で把握し，解剖学的指標にもとづいた剝離層を守ることにより安全に腹腔鏡下手術を行うことが可能と考えられた．

　A 63-year-old woman with abdominal pain was diagnosed with sigmoid colon cancer. Preoperative abdominal enhanced CT showed transposition of inferior vena cava（IVC） which is known as left sided IVC ; it ascends on the left side of the abdominal aorta and crosses the ventral side of the aorta to join normal pre-hepatic IVC. It is important to detect left sided IVC by preoperative imaging to prevent intra-operative injury. Furthermore, dissection while preserving the pre-hypogastric nerve fascia is especially important in performing sigmoidectomy. Even in cases with vascular anomaly like this case, laparoscopic surgery could be performed safely by preoperative diagnosis and detection of proper layer based on anatomical landmarks.