Mechanical and Oral Antibiotic Bowel Preparation in the Era of Minimally Invasive Surgery and Enhanced Recovery

Mechanical bowel preparation

At least 17 RCTs have compared the use of preoperative MBP (without oral antibiotic bowel preparation) versus no bowel preparation in patients undergoing elective colorectal surgery. In aggregate, these trials suggest that MBP is not associated with reductions in the incidence of SSI.^18,19 A 2011 Cochrane Review concluded that MBP has no significant impact on the incidence of infectious complications, anastomotic dehiscence, or mortality. ¹⁸ There is even a suggestion that MBP may promote infectious complications. In a RCT by Bucher et al. (2005), MBP administration was associated with a significantly higher incidence of a composite endpoint that included anastomotic leaks, intra-abdominal abscesses, and peritonitis (22% in MBP versus 8% in no MBP, P = .028). ²⁰

Based on these data, multiple authors have concluded that surgeons should omit MBP in elective open colorectal surgical procedures.^20–24 However, we note that data on the impact of MBP on SSI risk specifically in the context of laparoscopic surgery are limited.^20,25,26 Indeed, laparoscopic surgery was an exclusion criterion in some of the RCTs described above.^21,27

Oral antibiotic bowel preparation

A RCT evaluating oral antibiotic bowel preparation alone (without MBP) versus no bowel preparation is yet to be reported. For now, data on the efficacy of oral bowel preparation alone in reducing SSI risk are limited to retrospective database analyses. For example, in an analysis of the ACS-NSQIP Colectomy Targeted Dataset, oral antibiotic bowel preparation alone had no impact on incidence of SSI or other complications after colorectal surgery for inflammatory bowel disease. ²⁸ In contrast, a recent retrospective analysis of the same database compared no preparation, mechanical preparation alone, oral antibiotic preparation alone, and combined oral and antibiotic preparation and found that oral antibiotic preparation alone was protective against SSI, anastomotic leak, ileus, and major morbidity, but not mortality. ²⁹ This study also noted that combined oral antibiotic and MBP were protective of the aforementioned four metrics, in addition to mortality. ²⁹ Given the limited and conflicting data, we do not recommend oral antibiotic bowel preparation alone for minimally invasive colorectal surgery.

Combined mechanical and oral antibiotic bowel preparation

To the authors' knowledge, at least 19 RCTs have evaluated the effect of adding oral antibiotic bowel preparation to MBP in patients undergoing elective colorectal surgery.^30–32 Three of these RCTs revealed significant reductions in SSI with addition of oral antibiotic bowel preparation.^30,33,34 A recently reported RCT by Hata et al. revealed that patients undergoing laparoscopic colorectal procedures had a lower incidence of SSI (7.3% versus 12.8%, P = .028) when receiving oral antibiotic prophylaxis in addition to MBP. ³⁰ Similarly, in a RCT by Sadahiro et al., patients given oral antibiotics and MBP experienced lower incidences of SSI (6.1% versus 17.9%, P = .014) and anastomotic leak (1.0% versus 7.4%, P = .004) compared to patients who received preoperative MBP without oral antibiotics. ³⁵

In addition, a 2014 Cochrane Review found that the addition of oral antibiotics to preoperative intravenous antimicrobial prophylaxis in patients who received MBP reduced SSI by 45%. ³¹ Furthermore, a meta-analysis by Bellows et al. revealed that patients receiving oral nonabsorbable antibiotics as part of surgical antibiotic prophylaxis experienced a 43% risk reduction of SSI. ³²

Retrospective analysis of the ACS-NSQIP database revealed that patients receiving both oral antibiotic prophylaxis and MBP experienced a SSI incidence of 3.2% compared to 9% for those receiving no preparation (P < .001). ³⁶ Another retrospective review by Vo et al. found that patients receiving both MBP and oral antibiotics experienced an overall SSI rate of 8% compared to a rate of 27% in patients receiving MBP alone (P = .03). ³⁷

Other studies have indirectly examined the effect of combined antibiotic and MBP treatments by assessing patient outcomes in colorectal “bundles”.^38–40 A bundle is a systematic approach that incorporates the best interdisciplinary practices throughout the different phases of perioperative care, including preoperative MBP with oral antibiotics, intraoperative maintenance of euglycemia and normothermia, and postoperative wound care, to reduce postoperative infection rates. ³⁹ A study from the Michigan Surgical Quality Collaborative (2014) assigned “bundle scores” to each colorectal procedure. ³⁸ Each operation received a bundle score point if their patients received a “bundle measure” in their care. Bundle measure criteria included points for: appropriate prophylactic intravenous antibiotics, prophylactic oral antibiotics, minimally invasive surgery, short operative duration (<100 minutes), and other postoperative laboratory values. Patients who received all measures of a perioperative bundle, including MBP and oral antibiotics, had a 2.5% mean SSI rate compared to a 17.5% mean SSI rate in patients who received only one bundle measure. ³⁸ In a similar approach, Keenan et al. included MBP with oral antibiotics in their “preventative SSI bundle” for patients undergoing surgery. Patients receiving a bundle had significantly lower superficial SSI (5.6% versus 24.9%, P < .001) and postoperative sepsis (2.4% versus 10.4%, P < .001) rates compared to those who did not receive a bundle. ³⁹ Another study found that patients treated with oral antibiotics and MBP in infection prevention bundles for both open and laparoscopic colorectal procedures had a 2.7% SSI rate compared to a 15.8% SSI rate for those not receiving the bundle (P < .001). ⁴⁰

Bowel preparation and minimally invasive surgery

Several authors have noted the lack of RCT data comparing MBP with oral antibiotics to no MBP in laparoscopic surgery.^12,19 However, recent studies examining the role of bowel preparation have begun to include large numbers of laparoscopic cases, and the data suggest that MBP and oral antibiotics could lower infectious complications in laparoscopic surgery. ⁴¹ In a recent study of colorectal surgery for inflammatory bowel disease, in which approximately half of the 3600 patients studied underwent laparoscopic procedures, the combination of MBP and oral antibiotics significantly reduced rates of SSI, anastomotic leak, and sepsis. ²⁸ Over 2000 patients received MBP and oral antibiotics before laparoscopic colorectal surgery in an ACS-NSQIP database analysis by Kiran et al.; in this study MBP with (but not without) oral antibiotics was associated with significant reductions in incidence of SSI and of anastomotic leak. ⁴² Furthermore, another retrospective ACS-NSQIP data analysis, in which over 5000 patients underwent minimally invasive surgery, demonstrated that MBP in combination with oral antibiotics was associated with reductions in incidences of SSI and readmission and in hospital length of stay. ⁴³

Although data on the impact of bowel preparation in patients specifically undergoing minimally invasive colorectal surgery are limited, MBP can offer other benefits that most studies of bowel preparation have failed to address. These benefits are particularly relevant to minimally invasive procedures. First, MBP can enhance intraoperative bowel manipulation. Indeed, a RCT by Won et al. revealed that MBP improves both surgical viewing and bowel handling in laparoscopic procedures. ⁴⁴ In addition, MBP facilitates intraoperative colonoscopy, should it be required.^45–47 Given these potential benefits, the Society of Alimentary Gastrointestinal Endoscopic Surgeons (SAGES) recommends the use of MBP in laparoscopic surgeries to facilitate bowel manipulation during the procedure and to allow the surgeon to perform intraoperative colonoscopy if needed. ⁴⁶ As noted in the SAGES guidelines, a common indication for intraoperative endoscopy is the evaluation of colorectal anastomosis quality in the case of low anterior resections. ⁴⁶

Enhanced recovery after surgery

Enhanced recovery after surgery (ERAS) guidelines generally recommend against routine bowel preparation (particularly MBP) in elective colorectal surgery, citing adverse physiologic consequences such as dehydration and prolonged ileus.^12,48–50 However, ERAS recommendations by Gustafsson et al. note that most RCTs examining MBP have only included open colorectal procedures. ¹² The authors concede that the extrapolation of data from open procedures to laparoscopic surgery may be difficult. A recent survey of general surgeons found that only 20%–30% of surgeons omit MBP in colorectal surgery cases, highlighting that the majority of surgeons continue to use MBP in their standard practice. ⁵¹