The Role of Bowel Preparation in Colorectal Surgery

Results of the 2012-2015 ACS-NSQIP Data

Aaron L. Klinger, MD; Heather Green, MS; Dominique J. Monlezun, MD, PhD, MPH; David Beck, MD; Brian Kann, MD; Herschel D. Vargas, MD; Charles Whitlow, MD; David Margolin, MD


Annals of Surgery. 2019;269(4):671-677. 

In This Article

Abstract and Introduction


Objective: To analyze potential benefits with regards to infectious complications with combined use of mechanical bowel preparation (MBP) and ABP in elective colorectal resections.

Background: Despite recent literature suggesting that MBP does not reduce infection rate, it still is commonly used. The use of oral antibiotic bowel preparation (ABP) has been practiced for decades but its use is also controversial.

Methods: Patients undergoing elective colorectal resection in the 2012 to 2015 American College of Surgeons National Surgical Quality Improvement Program cohorts were selected. Doubly robust propensity score–adjusted multivariable regression was conducted for infectious and other postoperative complications.

Results: A total of 27,804 subjects were analyzed; 5471 (23.46%) received no preparation, 7617 (32.67%) received MBP only, 1374 (5.89%) received ABP only, and 8855 (37.98%) received both preparations. Compared to patients receiving no preparation, those receiving dual preparation had less surgical site infection (SSI) [odds ratio (OR) = 0.39, P < 0.001], organ space infection (OR = 0.56, P ≤ 0.001), wound dehiscence (OR = 0.43, P = 0.001), and anastomotic leak (OR = 0.53, P < 0.001). ABP alone compared to no prep resulted in significantly lower rates of surgical site infection (OR = 0.63, P = 0.001), organ space infection (OR = 0.59, P = 0.005), anastomotic leak (OR = 0.53, P = 0.002). MBP showed no significant benefit to infectious complications when used as monotherapy.

Conclusions: Combined MBP/ABP results in significantly lower rates of SSI, organ space infection, wound dehiscence, and anastomotic leak than no preparation and a lower rate of SSI than ABP alone. Combined bowel preparation significantly reduces the rates of infectious complications in colon and rectal procedures without increased risk of Clostridium difficile infection. For patients undergoing elective colon or rectal resection we recommend bowel preparation with both mechanical agents and oral antibiotics whenever feasible.


Cleansing the bowel to limit the infectious complications of colorectal surgery is hardly a new concept. In fact, in 1887 Halsted noted that "the chief danger of infection of the peritoneal cavity is manifestly from the contents of the intestine."[1] Shortly after the discovery of penicillin, surgeons began using oral antibiotics in attempts to reduce intraluminal bacterial counts. This was usually used in conjunction with purgatives or bowel irrigation to reduce stool burden and further reduce the bacterial counts. At the time these methods were being developed mortality rates for colorectal surgery was as high as 10% to 12% with as many as 90% of survivors developing surgical site infections (SSIs).[2] By the 1950s patients began to receive perioperative antibiotics and would often demand them regardless of their surgeon's recommendations.[3] In 1972 Nichols et al[4] introduced their protocol, still commonly used today, consisting of mechanical bowel preparation (MBP) and doses of neomycin and erythromycin which they found to reduce rates of SSI from 43% to 9%.

In recent years, the benefit of MBP has been called into question in various clinical trials.[5–8] In a 2011 Cochrane review Güenaga et al[9] analyzed more than 5800 colorectal surgery patients from 20 trials. They compared patients receiving MBP to patients receiving no preparation and found no significant difference between these groups in rates of anastomotic leakage or wound infection in colon or rectal resection. In 2015 Atkinson et al[10] found ABP alone to result in fewer SSIs than no preparation and questioned whether combined bowel preparation is necessary. Others have questioned if antibiotic bowel preparation offers any benefit when systemic intravenous antibiotics have been provided.[11,12] Furthermore, Wren et al[13] found oral antibiotics to result in increased rates of Clostridium difficile infection.

The high rate of infections and other postoperative complications in colorectal surgery and the desire to reduce hospital costs has led many surgeons to follow "fast-track" or "enhanced recovery pathways" (ERPs). These pathways vary but typically consist of limited perioperative fasting with early postoperative feeding, careful intravenous fluid management, attempts to limit postoperative nausea, vomiting, and ileus, and early discharge planning. Although some authors suggest using MBP as part of an ERP,[14–16] others insist a key component of enhanced recovery is avoidance of MBP.[17–20] In fact, recently published guidelines from the American Society of Colon and Rectal Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons recommend the use of combined MBP and ABP.[21]

Despite multisociety guidelines calling for the use of MBP and ABP in addition to IV antibiotic prophylaxis, the use of preparation remains controversial.[22] The Society of American Gastrointestinal and Endoscopic Surgeons recognizes this controversy and suggest that for colonic resection, if MBP is to be used, ABP must also be used. They note a lack of data for elective rectal surgery and do not make any specific recommendations.[23]

Surveys of the American Society of Colon and Rectal Surgeons have shown a trend in recent years toward abandoning preoperative bowel preparation. A 1990 survey by Beck and Fazio[24] found all respondents to use MBP and 87% to use oral antibiotics. Nichols created a similar survey in 1997 and again found 100% to use MBP and 88.5% using ABP plus IV antibiotics.[25] A 2003 survey by Zmora et al[26] found 99% of American Society of Colon and Rectal Surgeons (ASCRS) members to routinely use MBP and 75% to routinely use ABP, although only half thought ABP was essential. An ASCRS member survey by Markell et al[27] in 2010 found that 76% of respondents used MBP routinely before elective colectomy but only 36% used ABP routinely. Most recently in a 2016 ASCRS survey Beck and McCoy (Current perioperative management of the colorectal surgery patient: an ASCRS survey. unpublished observation. 2017) found only 59% to always use MBP and 48% to always use ABP.

We hypothesize that there is a significant benefit with regards to infectious complications with combined use of mechanical and antibiotic preparation in elective colorectal resections without an increased incidence of C. difficile infection.