A Rare Complication After Laparoscopic Lateral Lymph Node Dissection for Rectal Cancer: Two Case Reports of Internal Hernia Below the Superior Vesical Artery

Total mesorectal excision or mesorectal excision with lateral lymph node dissection (LLND) is a standard treatment for locally advanced lower rectal cancer in Japan. Although laparoscopic LLND for rectal cancer is technically complex and challenging, previous studies have demonstrated its feasibility, and the procedure is gradually becoming more common. With this increased use, the incidence of new complications specific to laparoscopic LLND is likely to increase, and a greater awareness of these complications is required. Here we report two cases of internal hernia of the small bowel through an orifice of the vesicohypogastric fascia below the superior vesical artery after laparoscopic LLND. There are six previous reports of internal hernia underneath the pelvic blood vessel after pelvic lymph node dissection for urological or gynecological malignancies, but our cases are the first two that occurred after LLND for rectal cancer. Almost all cases, including our two cases, occurred after laparoscopic surgery and required resection of an incarcerated small bowel. Therefore, the incidence of this complication is likely to increase as the number of cases treated with laparoscopic LLND increases. Our cases show that it is important to perform an emergency operation promptly instead of conservative treatment.