Review: mechanical bowel preparation before colorectal surgery does not provide any benefit and may be harmful
Does mechanical bowel preparation (MBP) before colorectal surgery provide any benefit?
Included studies compared MBP with no MBP before elective colorectal surgery for malignant or benign conditions. Outcomes included anastomotic leakage, pelvic or abdominal abscess, and surgical site infection.
Medline, Scopus, and Cochrane Library (to Jan 2008); recent issues of major surgical journals; proceedings of major meetings; and reference lists were searched for randomised controlled trials (RCTs). 14 RCTs (n = 4859) met the selection criteria. All but 1 trial enrolled only adults.
Groups did not differ for anastomotic leakage or pelvic or abdominal abscess (table). Surgical site infections were more frequent in the MBP group (table). Relative risks of adverse outcomes were similar whether polyethylene glycol (9 RCTs, n = 3619) or sodium phosphate (4 RCTs, n = 2253) was the solution used.
Mechanical bowel preparation before colorectal surgery does not provide any benefit but may increase risk of infection.
Slim K, Vicaut E, Launay-Savary MV, et al. Updated systematic review and meta-analysis of randomized clinical trials on the role of mechanical bowel preparation before colorectal surgery. Ann Surg 2009;249:203–9.
MBP before colorectal surgery is a practice that dates back to the 1940s despite a lack of empirical evidence to support its use. Since the 1970s, trials have shown no benefit of MBP to postoperative recovery, and indeed, some trials have suggested that MBP may cause harm.1 However, practice has remained unchanged because earlier trials were considered too small, inaccurate, or underpowered. Recent larger, multicentre RCTs have been more structurally and statistically robust. Evidence from these RCTs provided impetus for Slim et al to update their earlier systematic review.2
This re-evaluation of the evidence is a methodologically rigorous review that provides a clear account of purpose, process, and results. 14 RCTs, including 2 new large trials, were examined, and meta-analysis was applied according to the QUOROM statement. Regardless of solution used, the results clearly show that MBP provides no benefit. The conclusion was that MBP should not be done before colonic surgery.
Similar results were found and the same conclusions drawn in a Cochrane review by Guenaga et al, which included 13 RCTs.3 Given the strength of the current evidence, use of MBP before colorectal surgery should become a thing of the past. This conclusion supports previous observational findings that MBP is distressing for patients, slows time to bowel emptying postoperatively,4 and has resource implications. Research should now address the complex issue of how changes in practice can be implemented.