Bowel preparation in colorectal surgery: the day of reckoning is here

A Network Meta-Analysis and GRADE Assessment of the Effect of Preoperative Oral Antibiotics with and Without Mechanical Bowel Preparation on Surgical Site Infection Rate in Colorectal Surgery

Objective

To compare the effect of different methods of bowel preparation on the incidence of surgical site infections (SSI), anastomotic leakage (AL), and mortality in patients undergoing elective colorectal surgery.

Background

Recent guidelines advise mechanical bowel preparation with oral antibiotics (MBP-OA) for the prevention of SSI in colorectal surgery. Recent trials suggest oral antibiotics (OA) alone may be sufficient.

Methods

PubMed, MEDLINE, and Embase were searched from inception until 10-08-2021. We included randomized controlled trials (RCTs) comparing multiple methods of bowel preparation (mechanical bowel preparation [MBP], OA, MBP-OA, or no preparation) with regards to clinical outcomes such as incidence of SSI, AL, and mortality rates. A frequentist random-effects network meta-analysis was conducted to estimate the network effects of the different treatment options.

Results

We included 48 studies with 13,611 patients. Compared to no preparation, combined direct and indirect network estimates showed a relative risk (RR) for SSI of 0.57 (95% confidence interval [CI], 0.45-0.72) for MBP-OA, 0.68 (95% CI, 0.49-0.95) for OA, and 1.05 (95% CI, 0.87-1.26) for MBP. The RR for MBP-OA compared to OA was 0.84 (95% CI, 0.60-1.19); in sensitivity analysis of mainly laparoscopic procedures this effect of MBP-OA was more profound (RR, 0.56; 95% CI, 0.31-0.99).

Conclusions

This network meta-analysis of RCTs finds that both mechanical bowel preparation with oral antibiotics and oral antibiotics alone are comparably effective in the prevention of SSI. The evidence is uncertain about the relative benefit of MBP-OA compared to OA alone. Therefore, it seems justified to use either of the 2 for the prevention of SSI in colorectal surgery.

Bowel decontamination before colonic and rectal surgery

Several strategies are available to reduce adverse events after colonic and rectal surgery. Oral and intravenous antibiotics have proven efficacy in reducing surgical-site infections, and might be beneficial against anastomotic leaks. The role of mechanical bowel preparation needs further elucidation.