Mechanical bowel preparation to prevent infective complications after colon and rectal surgery: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION: Surgical site infections (SSI) represent a global health challenge, particularly in colorectal surgery, when rates can reach up to 20%. The role of mechanical bowel preparation (MBP) is still debated. A systematic review is proposed to evaluate MBP effectiveness in reducing SSI and complications after colorectal surgery. EVIDENCE ACQUISITION: This systematic review and meta-analysis was conducted following the PRISMA guidelines. Only randomized studies comparing two or more methods for preventing infectious complications in patients undergoing colorectal surgery were included. The primary endpoint was the occurrence of SSIs, while secondary endpoints included anastomotic leak (AL) and intra-abdominal septic complications (IASC) other than AL. EVIDENCE SYNTHESIS: Eighteen studies met the inclusion criteria, including a total of 6,302 patients in the analysis. The meta-analysis showed similar SSI rates between the MBP and no-treatment groups (OR 1.015, 95% CI 0.855-1.206, I2=22.33%, P=0.863) as well as between the MBP and enema groups (OR 1.100, 95% CI 0.616-1.965, I2=35.96%, P=0.748). The risk of anastomotic leak (AL) was also similar when comparing no treatment to MBP (OR 0.904, 95% CI 0.661-1.237, I2=0%, P=0.528), and MBP to enema (OR 0.727, 95% CI 0.286-1.845, I2=25.98%, P=0.502). IASC rates were lower with MBP compared to no treatment (OR 0.526, 95% CI 0.326-0.848, I2=3.50%, P=0.008). CONCLUSIONS: This meta-analysis found no significant reduction in SSI or AL rates with MBP alone compared to no preparation or enema use. However, MBP significantly lowered IASC. Further research is warranted to evaluate the effectiveness of MBP combined with antibiotics in reducing postoperative complications.