The value of mechanical bowel preparation in elective colorectal surgery: an updated meta-analysis and systematic review

The necessity for bowel preparation in elective colorectal surgery (ECS) is still a topic of considerable discussion. The choice to implement mechanical bowel preparation (MBP) is part of the preoperative process, yet there are no established standards in the changing landscape of clinical practice. This comprehensive analysis seeks to assess the effectiveness of MBP in ECS, offering valuable insights for informed clinical decision-making. A comprehensive systematic search of English and Chinese databases—including PubMed, Cochrane Library, Embase, Web of Science, Chinese Biomedical Literature Database (CBM), VIP Database, China National Knowledge Infrastructure (CNKI), and Wanfang—was conducted from inception through March 31, 2025. Only randomized controlled trials were eligible for inclusion. Two reviewers independently extracted study data and assessed risk of bias using the Cochrane ROB2 tool. The target population comprised adults undergoing elective colorectal surgery. Prespecified outcomes were intra-abdominal abscess, anastomotic leakage, wound dehiscence, surgical-site infection, and urinary tract infection. Effect estimates were expressed as relative risks (RR) with 95% confidence intervals. A comprehensive analysis was conducted on 18 RCTs, encompassing an aggregate of 5,930 individuals. Within this cohort, 2,982 individuals were assigned to the MBP group, while 2,948 individuals were included in the non-bowel preparation group (non-MBP). Meta-analysis demonstrated no significance in statistics differences among the MBP and the non-MBP cohorts in anastomotic leakage incidence (RR = 1.07, 95% CI: 0.84–1.36, p = 0.60), wound infection incidence (RR = 1.12, 95% CI: 0.96–1.30, p = 0.16), intra-abdominal abscess incidence (RR = 0.75, 95% CI: 0.53–1.06, p = 0.10), wound dehiscence incidence (RR = 1.31, 95% CI: 0.75–2.28, p = 0.34) and urinary tract infection incidence (RR = 1.08, 95% CI: 0.68–1.70, p = 0.75). The current evidence does not demonstrate a clear benefit of mechanical bowel preparation prior to elective colorectal surgery, and routine use cannot be recommended. No statistically significant differences were observed between MBP and non-MBP groups for anastomotic leakage, surgical-site infection, intra-abdominal abscess, wound dehiscence, or urinary tract infection, and confidence intervals for key outcomes do not exclude the possibility of clinically meaningful harm.