Impact of mechanical bowel preparation in elective colorectal surgery: A meta-analysis

Abstract

Aim: To analyse the effect of mechanical bowel preparation vs no mechanical bowel preparation on outcome in patients undergoing elective colorectal surgery.

Methods: Meta-analysis of randomised controlled trials and observational studies comparing adult patients receiving mechanical bowel preparation with those receiving no mechanical bowel preparation, subdivided into those receiving a single rectal enema and those who received no preparation at all prior to elective colorectal surgery.

Results: A total of 36 studies (23 randomised controlled trials and 13 observational studies) including 21568 patients undergoing elective colorectal surgery were included. When all studies were considered, mechanical bowel preparation was not associated with any significant difference in anastomotic leak rates (OR = 0.90, 95%CI: 0.74 to 1.10, P = 0.32), surgical site infection (OR = 0.99, 95%CI: 0.80 to 1.24, P = 0.96), intra-abdominal collection (OR = 0.86, 95%CI: 0.63 to 1.17, P = 0.34), mortality (OR = 0.85, 95%CI: 0.57 to 1.27, P = 0.43), reoperation (OR = 0.91, 95%CI: 0.75 to 1.12, P = 0.38) or hospital length of stay (overall mean difference 0.11 d, 95%CI: -0.51 to 0.73, P = 0.72), when compared with no mechanical bowel preparation, nor when evidence from just randomized controlled trials was analysed. A sub-analysis of mechanical bowel preparation vs absolutely no preparation or a single rectal enema similarly revealed no differences in clinical outcome measures.

Conclusion: In the most comprehensive meta-analysis of mechanical bowel preparation in elective colorectal surgery to date, this study has suggested that the use of mechanical bowel preparation does not affect the incidence of postoperative complications when compared with no preparation. Hence, mechanical bowel preparation should not be administered routinely prior to elective colorectal surgery.

Keywords: Antibiotics; Bowel preparation; Mechanical; Meta-analysis; Morbidity; Mortality; Outcome complications; Surgery.

Figure 1

PRISMA diagram showing identification of relevant studies from initial search, PRISMA: Preferred reporting Items for systematic reviews and meta-analyses.

Figure 2

Forest plot comparing overall anastomotic leak rate for patients receiving mechanical bowel preparation vs either a single rectal enema (top) or absolutely no preparation (bottom). A Mantel-Haenszel random effects model was used to perform the meta-analysis and odds ratios are quoted including 95% confidence intervals. MBP: Mechanical bowel preparation.

Figure 3

Forest plot comparing overall surgical site infection rates for patients receiving mechanical bowel preparation vs either a single rectal enema (top) or absolutely no preparation (bottom). A Mantel-Haenszel random effects model was used to perform the meta-analysis and odds ratios are quoted including 95% confidence intervals. MBP: Mechanical bowel preparation.

Figure 4

Forest plot comparing overall intra-abdominal collection rates for patients receiving mechanical bowel preparation vs either a single rectal enema (top) or absolutely no preparation (bottom). A Mantel-Haenszel random effects model was used to perform the meta-analysis and odds ratios are quoted including 95% confidence intervals. MBP: Mechanical bowel preparation.

Figure 5

Forest plot comparing overall hospital length of stay for patients receiving mechanical bowel preparation vs either a single rectal enema (top) or absolutely no preparation (bottom). An inverse-variance random effects model was used to perform the meta-analysis and mean differences are quoted including 95% confidence intervals. MBP: Mechanical bowel preparation.

Figure 6

Forest plot comparing overall mortality rates for patients receiving mechanical bowel preparation vs either a single rectal enema (top) or absolutely no preparation (bottom). A Mantel-Haenszel random effects model was used to perform the meta-analysis and odds ratios are quoted including 95% confidence intervals. MBP: Mechanical bowel preparation.

Figure 7

Forest plot comparing overall reoperation rates for patients receiving mechanical bowel preparation vs either a single rectal enema (top) or absolutely no preparation (bottom). A Mantel-Haenszel random effects model was used to perform the meta-analysis and odds ratios are quoted including 95% confidence intervals. MBP: Mechanical bowel preparation.