Best practices in bowel preparation for colorectal surgery: a 2020 overview.

INTRODUCTION: Cohort studies have recently initiated a paradigm shift in the field of preoperative bowel preparation. Indeed, the adjunction of oral antibiotics (OAB) to mechanical bowel preparation (MBP) is now the gold standard for the American guidelines. However, this strategy is highly controverted. AREAS COVERED: This review was an up-to-date analysis of literature on bowel preparation. We conducted a systematic review for randomized controlled trials (RCTs) and meta-analyses published since 2009. A non-exhaustive overview of the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) cohort studies and the international guidelines was also given, and future leads were discussed. EXPERT OPINION: The methodology of the ACS NSQIP studies did not allow a strong conclusion in favor of the association MBP+OAB. Besides, guidelines were not univocal, with non-American guidelines promoting no preparation at all. RCTs favored OAB alone: indeed, MBP+OAB showed no benefits in terms of surgical site infection (SSI) except when compared to MBP alone, while OAB alone seemed superior to no preparation. Likewise, the meta-analyses also favored OAB alone in terms of overall SSI and organ space infection. Large RCTs are currently running and may change these conclusions. Finally, microbiota is a future lead for personalized OAB.