Where Do You Stand on Mechanical Bowel Preparation for Patients Undergoing Colorectal Surgery?

Q: There have been a number of papers in the literature debating the use of mechanical bowel preparation for patients undergoing colorectal surgery. What are your thoughts?

A: The use of mechanical bowel preparation has been around for a long time and it’s been studied in many randomized, controlled trials. Over the past one and a half decades, these studies have suggested that bowel preparation may not reduce the chance of surgical site infection or anastomotic leak for patients.

As taking a mechanical bowel preparation is not particularly pleasant ― often associated with nausea or vomiting and can dehydrate the patient before surgery ― many surgeons thought this would be a way to help our patients and have them avoid needing to take a bowel prep.

What these studies missed, however, was that the populations evaluated were often quite varied. Sometimes inflammatory bowel disease was included, sometimes it wasn’t. Sometimes an abdominal or pelvic abscess was counted as a leak, sometimes it wasn’t. And some of the studies that showed that avoiding a bowel prep did not make a difference would have reported different findings had abscesses and anastomotic leaks been counted together.

In my practice doing laparoscopic surgery, I’ve always approached the subject thinking that the bowel prep was equivalent to no bowel prep. But for doing laparoscopic surgery, it was much easier to handle a clean colon and there was never the challenge of having of dealing with a full colon when doing an anastomosis.

However, everything really changed about 10 years ago as the literature increasingly showed that the use of oral antibiotics with the mechanical bowel prep reduced complications more than the mechanical bowel prep alone. This has now been substantiated in several meta-analyses and is also supported by several population-based analyses, such as the NSQIP analysis and the Michigan Surgical Quality Collaborative analysis.

To my mind, the data adequately shows that an oral antibiotic and mechanical bowel prep reduces surgical site infection and may, in addition, reduce anastomotic leak rates over mechanical bowel prep alone. Personally, I think that the discussion of whether to use or avoid a bowel prep is, therefore, a moot point. And so, in our practice at Cleveland Clinic, we use a mechanical bowel prep with oral antibiotics as part of our standardized preoperative care plan.

There may be space in the future to conduct a randomized trial to evaluate oral antibiotics alone or to re-evaluate mechanical bowel prep with oral antibiotics. However, this would need to be an extremely large and well-prepared trial ― making it extremely expensive. I personally think the evidence we have at the present time is sufficient to continue with oral antibiotics and mechanical bowel prep for the foreseeable future.

— Conor Delaney, MD, PhD
Chairman, Digestive Disease & Surgery Institute
Cleveland Clinic