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.
METHODS: 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.
CONCLUSIONS: 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.

BACKGROUND: Diverticulitis is one of the most common gastrointestinal diseases in western population. Colonic resection is recommended by international guidelines as a routinely used technique for purulent diverticulitis. Laparoscopic lavage was introduced as a non-resection alternative. The studies available so far have shown contradictory results. This meta-analysis aims to compare laparoscopic lavage versus colonic resection in patients with Hinchey Ⅲ-Ⅳ diverticulitis.
METHODS: We did a systematic review of articles published before March 20, 2019, with no language restriction by searching PubMed, Cochrane library, EMBASE databases, clinicaltrials.gov, and Google Scholar databases. We included all RCTs and cohort studies comparing outcomes between patients with Hinchey Ⅲ-Ⅳ diverticulitis undergoing laparoscopic lavage versus colonic resection. Important outcomes were mortality, complications, length of stay, readmission and reoperation rates. We combined data to assess the outcomes using DerSimonian and Laird random-effects model.
RESULTS: A total of 569 patients with diverticulitis of which more than 80% were Hinchey Ⅲ were enrolled from 3 RCTs and 5 cohort studies. Laparoscopic lavage was associated with shorter operative time (WMD -78.9, 95%CI -100.58 to -57.11, P < 0.0001) and total postoperative hospital stay (WMD -7.62, 95%CI -11.60 to -3.63, P = 0.0002) but a higher rate of intra-abdominal abscess (OR 2.69, 95%CI 1.39 to 5.21, P = 0.0032) and secondary peritonitis (OR 5.30, 95%CI 1.91 to 14.73, P = 0.0014).
CONCLUSIONS: Laparoscopic lavage for patients with Hinchey Ⅲ to Ⅳ diverticulitis does provide similar mortality, shorter operative time and hospital stay. However, the evidence so far suggests that it might be inadequate for sepsis control and may result in more unplanned reoperations. Further studies are needed to standardize the formal indication for laparoscopic lavage.