Mechanical bowel preparation and antibiotics in elective colorectal surgery: network meta-analysis

Antibiotic prophylaxis for the prevention of surgical site infections following colorectal surgery: protocol for network meta-analysis of randomized trials

BACKGROUND

Surgical site infections continue to be a significant challenge following colorectal surgery. These can result in extended hospital stays, hospital readmissions, increased treatment costs, and negative effects on patients' quality of life. Antibiotic prophylaxis plays a crucial role in preventing infection during surgery, specifically in preventing surgical site infections after colorectal surgery in adult patients. However, the optimal antibiotic regimen is still unclear based on current evidence. Considering the limitations of existing reviews, our goal is to conduct a comprehensive systematic review and network meta-analysis of randomized controlled trials to evaluate the comparative benefits and harms of available antibiotic prophylaxis regimens for preventing surgical site infections following colorectal surgery in adult patients.

METHODS

We will search the Medline, EMBASE, CINAHL, Scopus, and Cochrane Central Register of Controlled Trials databases to identify relevant randomized controlled trials. We will include trials that (1) enrolled adults who underwent colorectal surgeries and (2) randomized them to any systemic administration of antibiotic (single or combined) prophylaxis before surgery compared to an alternative systemic antibiotic (single or combined antibiotic), placebo, control, or no prophylactic treatment. Pairs of reviewers will independently assess the risk of bias among eligible trials using a modified Cochrane risk of bias instrument for randomized trials. Our outcomes of interest include the rate of surgical site infection within 30 days of surgery, hospital length of stay, 30-day mortality, and treatment-related adverse effects. We will perform a contrast-based network meta-analysis using a frequentist random-effects model assuming a common heterogeneity parameter. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach will be utilized to assess the certainty of evidence for treatment effects.

DISCUSSION

By synthesizing evidence from available RCTs, this study will provide valuable insight for clinicians, patients, and health policymakers on the most effective antibiotics for preventing surgical site infection.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42023434544.

Morbidity After Mechanical Bowel Preparation and Oral Antibiotics Prior to Rectal Resection: The MOBILE2 Randomized Clinical Trial

Importance

Surgical site infections (SSIs)-especially anastomotic dehiscence-are major contributors to morbidity and mortality after rectal resection. The role of mechanical and oral antibiotics bowel preparation (MOABP) in preventing complications of rectal resection is currently disputed.

Objective

To assess whether MOABP reduces overall complications and SSIs after elective rectal resection compared with mechanical bowel preparation (MBP) plus placebo.

Design, Setting, and Participants

This multicenter, double-blind, placebo-controlled randomized clinical trial was conducted at 3 university hospitals in Finland between March 18, 2020, and October 10, 2022. Patients aged 18 years and older undergoing elective resection with primary anastomosis of a rectal tumor 15 cm or less from the anal verge on magnetic resonance imaging were eligible for inclusion. Outcomes were analyzed using a modified intention-to-treat principle, which included all patients who were randomly allocated to and underwent elective rectal resection with an anastomosis.

Interventions

Patients were stratified according to tumor distance from the anal verge and neoadjuvant treatment given and randomized in a 1:1 ratio to receive MOABP with an oral regimen of neomycin and metronidazole (n = 277) or MBP plus matching placebo tablets (n = 288). All study medications were taken the day before surgery, and all patients received intravenous antibiotics approximately 30 minutes before surgery.

Main Outcomes and Measures

The primary outcome was overall cumulative postoperative complications measured using the Comprehensive Complication Index. Key secondary outcomes were SSI and anastomotic dehiscence within 30 days after surgery.

Results

In all, 565 patients were included in the analysis, with 288 in the MBP plus placebo group (median [IQR] age, 69 [62-74] years; 190 males [66.0%]) and 277 in the MOABP group (median [IQR] age, 70 [62-75] years; 158 males [57.0%]). Patients in the MOABP group experienced fewer overall postoperative complications (median [IQR] Comprehensive Complication Index, 0 [0-8.66] vs 8.66 [0-20.92]; Wilcoxon effect size, 0.146; P < .001), fewer SSIs (23 patients [8.3%] vs 48 patients [16.7%]; odds ratio, 0.45 [95% CI, 0.27-0.77]), and fewer anastomotic dehiscences (16 patients [5.8%] vs 39 patients [13.5%]; odds ratio, 0.39 [95% CI, 0.21-0.72]) compared with patients in the MBP plus placebo group.

Conclusions and Relevance

Findings of this randomized clinical trial indicate that MOABP reduced overall postoperative complications as well as rates of SSIs and anastomotic dehiscences in patients undergoing elective rectal resection compared with MBP plus placebo. Based on these findings, MOABP should be considered as standard treatment in patients undergoing elective rectal resection.

Trial Registration

ClinicalTrials.gov Identifier: NCT04281667.

Is mechanical bowel preparation mandatory for elective colon surgery? A systematic review and meta-analysis

BACKGROUND

Growing evidence demonstrates minimal impact of mechanical bowel preparation (MBP) on reducing postoperative complications following elective colectomy. This study investigated the necessity of MBP prior to elective colonic resection.

METHOD

A systematic literature review was conducted across PubMed, Ovid, and the Cochrane Library to identify studies comparing the effects of MBP with no preparation before elective colectomy, up until May 26, 2023. Surgical-related outcomes were compiled and subsequently analyzed. The primary outcomes included the incidence of anastomosis leakage (AL) and surgical site infection (SSI), analyzed using Review Manager Software (v 5.3).

RESULTS

The analysis included 14 studies, comprising seven RCTs with 5146 participants. Demographic information was consistent across groups. No significant differences were found between the groups in terms of AL ((P = 0.43, OR = 1.16, 95% CI (0.80, 1.68), I2 = 0%) or SSI (P = 0.47, OR = 1.20, 95% CI (0.73, 1.96), I2 = 0%), nor were there significant differences in other outcomes. Subgroup analysis on oral antibiotic use showed no significant changes in results. However, in cases of right colectomy, the group without preparation showed a significantly lower incidence of SSI (P = 0.01, OR = 0.52, 95% CI (0.31, 0.86), I2 = 1%). No significant differences were found in other subgroup analyses.

CONCLUSION

The current evidence robustly indicates that MBP before elective colectomy does not confer significant benefits in reducing postoperative complications. Therefore, it is justified to forego MBP prior to elective colectomy, irrespective of tumor location.

The Impact of Mechanical Bowel Preparation and Oral Antibiotics in Colorectal Cancer Surgery (MECCA Study): A Prospective Randomized Clinical Trial

Background: Colorectal cancer surgery has been associated with surgical site infections (SSIs), leading to an increase in postoperative morbidity, length of stay and total cost. The aim of the present randomized study was to investigate the relationship between the preoperative administration of oral antibiotic therapy and SSI rate, as well as other postoperative outcomes in patients undergoing colorectal cancer surgery. Material and Methods: Patients who underwent colorectal cancer surgery in a university surgical department were included in the present study. Patients were randomized into two groups using the "block randomization" method. The intervention group received three doses of 400 mg rifaximin and one dose of 500 mg metronidazole per os, as well as mechanical bowel preparation the day before surgery. The control group underwent only mechanical bowel preparation the day before surgery. The study has been registered in ClinicalTrials.gov (NCT03563586). Results: Two hundred and five patients were finally included in the present study, 97 of whom received preoperative antibiotic therapy per os (intervention group). Patients of this group demonstrated a significantly lower SSI rate compared with patients who did not receive preoperative antibiotic therapy (7% vs. 16%, p = 0.049). However, preoperative antibiotic administration was not correlated with any other postoperative outcome (anastomotic leak, overall complications, readmissions, length of stay). Conclusions: Preoperative antibiotic therapy in combination with mechanical bowel preparation seemed to be correlated with a lower SSI rate after colorectal cancer surgery.