Does mechanical bowel preparation have a role in preventing postoperative complications in elective colorectal surgery?

BACKGROUND mechanical bowel preparation (MBP) consists of orthograde fluid preparation to clean the bowel. MBP is considered to prevent postoperative complications. METHODS meta-analysis of prospective randomised clinical trials (RCT) evaluating MBP versus no MBP. RESULTS following a medline search we retrieved 15 prospective trials of which only 5 where RCT comparing MBP versus no MBP in elective colorectal surgery. For the randomised studies, there were respectively 186, 179, 149, 267 and 380 patients, including all type of resections. The total number of patients in these 5 studies was 1144 (565 with MBP and 579 with no preparation). All patients received perioperative antibiotic prophylaxis. Only one of these RCT show a significant decrease in anastomotic leak (AL), but among all the patients enrolled, AL is significantly more frequent in the group with MBP (Odds Ratio 1.8). Wound infection, re-operation and intra-abdominal abscess rates were more frequent in the MBP group but the difference did not reach statistical significance and the odds ratios for a 95% confidence interval were extremely large. CONCLUSION there is limited evidence in the literature to support the use of MBP in patient undergoing elective colorectal surgery. Available data tend to suggest that MBP could be harmful with respect to the incidence of anastomotic leak. Moreover, MBP does not reduce the incidence of other infectious complications. Further RCTs are needed to establish an evidence-based rationale for the use of MBP in elective colorectal surgery.