End-to-end versus end-to-side anastomosis for low anterior resection: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Numerous randomized controlled trials comparing end-to-end and end-to-side anastomoses after low anterior resection have been performed. Rates of anastomotic leakage and overall postoperative morbidity, as well as reported quality of postoperative bowel function, vary across individual studies. As such, this study meta-analyzes pooled data comparing end-to-end and end-to-side anastomosis after low anterior resection in terms of anastomotic leak rate and postoperative bowel function. METHODS: A search of Medline, EMBASE, and Cochrane Central Register of Controlled Trials was performed. Articles were included if they were randomized controlled trials that compared end-to-end and end-to-side anastomosis after low anterior resection for benign or malignant disease. The primary outcome was anastomotic leak rate. A pairwise meta-analysis was performed using inverse variance random effects. RESULTS: From 1,452 citations, 6 randomized controlled trials with 270 patients undergoing end-to-end anastomosis (45.9% female, mean age: 63.5 years) and 268 patients undergoing end-to-side anastomosis (52.4% female, mean age: 64.0 years) met inclusion criteria. Patients undergoing end-to-side anastomosis had a significantly lower rate of anastomotic leak (RR 0.37, 95% CI 0.15-0.93, P = .04, I²=0%). There were no differences in rate of anastomotic stenosis (RR 1.03, 95% CI 0.21-5.19, P = .97) or overall postoperative morbidity (RR 0.60, 95% CI 0.33-1.07, P = .08). Narrative review of postoperative bowel function demonstrated evidence of improved Wexner scores for 6 months postoperatively in patients undergoing end-to-side anastomosis. CONCLUSION: End-to-side anastomosis significantly reduces the risk of anastomotic leak after low anterior resection. Additional prospective trials are warranted to confirm the findings of this review and to contribute to the growing evidence-base aimed at optimization of bowel function after low anterior resection.