Side-to-side versus end-to-side ileocolic anastomosis in right-sided colectomies: A cohort control study.

Aims: The three main types of anastomotic configurations following colorectal resection are Side-to-Side Anastomosis (S-S), End-to-Side Anastomosis (E-S) and End-to-End Anastomosis (E-E). This study aims to present results from a local cohort supplemented by a systematic review with meta-analysis of existing literature to compare the post-operative outcomes between E-S and S-S. Methods: A cohort study of patients who underwent right colectomy with E-S or S-S anastomosis, was conducted at the National University Hospital Singapore. Electronic databases Embase and Medline were systematically searched from inception to 21 August 2020, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Studies were included if they compared post-operative outcomes between E-S and S-S. Results: In the cohort study, 40 underwent E-S and 154 underwent S-S. Both post-operative ileus (12.5% vs. 29.2%, P = 0.041) and length of hospital stay (9.35 days vs. 14.04 days, P = 0.024) favoured E-S, but anastomotic bleed favoured S-S (15.0% vs. 3.2%, P = 0.004). Five studies were included in the meta-analysis with 860 E-S and 1126 S-S patients. Similarly, post-operative ileus (odds ratio [OR] =0.302; 95% confidence interval [CI]: 0.122-0.747; P = 0.010) and length of hospital stay (mean differences = ‒1.54 days; CI: ‒3.00 to ‒0.076 days; P = 0.039) favoured E-S. Additional sensitivity analysis including only stapled anastomosis showed a lower rate of anastomotic leak in E-S patients (OR = 0.185; 95% CI: 0.054-0.627; P = 0.007). Conclusions: This is the first systematic review to show that the E-S technique produces superior post-operative outcomes after right colectomy compared to S-S. However, the choice of anastomosis was largely surgeon dependent, but surgeon factors were not reported.