Bowel Preparation Before Elective Colorectal Surgery: What is the Evidence

Mechanical and antibiotic bowel preparation is a time tested procedure that when done appropriately, significantly reduces the risk of infectious complications of colorectal surgical procedures, surgical site infections, and anastomotic dehiscence. Currently, a 3-tier regimen, which includes preoperative mechanical cleansing to reduce the fecal load, preoperative nonabsorbed oral antimicrobials effective against both aerobic and anaerobic bacteria, and perioperative parenteral antibiotics is most commonly used in the US. The vast majority of surgeons in the US today consider this approach as the cornerstone of elective colorectal surgery. However, randomized clinical trials from several countries have concluded that the role of mechanical and antibiotic bowel preparation should be re-evaluated. To date, there have been numerous randomized clinical trials comparing preoperative mechanical preparation to no preparation in patients undergoing elective colorectal surgery. When combined in meta-analyses, however, there is no statistically significant evidence that patients benefit from either mechanical or antibiotic bowel preparation. The data are overwhelming that the dogma regarding bowel preparation before elective colorectal surgery should be abandoned.