Mechanical bowel preparation for colorectal surgery: a meta-analysis on abdominal and systemic complications on almost 5,000 patients

Background Several studies concluded that mechanical bowel preparation (MBP) does not confer any advantage on reducing the anastomotic leak rate or wound infections. The aim of this meta-analysis was to review all prospective randomised controlled trials on the use of MBP before colorectal surgery in order to find differences in the rates of abdominal and systemic complications in view of recent published articles. Methods Review of all randomised prospective trials compare MBP vs. non-MBP. Primary outcome measures were anastomotic leakages, abdomino-pelvic abscesses and postoperative ileus. Secondary outcomes were wound infections, extra-abdominal complications (urinary infections, pulmonary infections, deep venous thrombosis or pulmonary embolism, cardiac events), sepsis and mortality. Results Twelve articles met the inclusion criteria with 4,919 patients. The non-MBP group showed no significant increase of the anastomotic leakages (3.4% vs. 4.1%; p = NS) and wound infections (8.7% vs. 9.6%; p = NS) but had a lower rate of postoperative cardiac events (2.5% vs. 4.0%; p = 0.04). Conclusion The evidence from recent studies, combined with previous ones, further suggests that the dogma of the necessity of mechanical bowel preparation before elective colorectal surgery should be reconsidered.