OBJECTIVETo investigate the effect of ligation level of inferior mesenteric artery (IMA) on postoperative defecation function in patients with rectal cancer.

METHODSA total of 128 rectal cancer patients who were planned to undergo low anterior resection in the First Hospital of Zibo City between January 1, 2012 and December 31, 2013 were prospectively enrolled and randomly divided into IMA high ligation group(63 cases, cutting distance of 1.0 to 1.5 cm to the root of IMA) and low ligation group(65 cases, cutting distance of 0.5 to 1.0 cm to the root of left colic artery originated from IMA). The efficacy, especially the defecation function, was observed and compared 3 months and 1 year after surgery between the two groups.

RESULTSNo significant difference was found in the number of harvested lymph nodes between two groups[8(1-30) vs. 7(2-28), P=0.125], but high ligation group had greater number of metastatic lymph nodes[1(0-9) vs. 0(0-8), P=0.041]. Frequency of defecation in high ligation group was significantly higher than that in low ligation group during postoperative 3-month follow-up[5(2-10)/d vs. 3(1-8)/d, P=0.035], whereas other indexes of defecation function were not significantly different(all P>0.05). The proportion of patients needing laxatives in high ligation group was higher than that in low ligation group during postoperative 1-year follow-up [11.3%(6/53) vs. 1.7%(1/58), P=0.038], whereas other indexes of defecation function were not significantly different as well (all P>0.05). Three cases and 2 cases showed recurrence in high ligation group and low ligation group respectively during postoperative 1-year follow-up without significant difference(P=0.623).

CONCLUSIONLow ligation of IMA in low anterior resection for rectal cancer is beneficial to the protection against defecation function.