To prep, or not? Evidence is against mechanical bowel preparation in gynecologic surgery

Easing bowel manipulation

Some gynecologists continue to use MBP in cases at low risk for bowel injury because they are concerned about the ease of operation and want to ensure good visibility, particularly when laparoscopy is involved. Muzii and colleagues conducted a randomized, single-blinded study of MBP versus no preparation in benign cases managed by gynecologic laparoscopy. The surgeons were blinded as to whether or not the patient had undergone MBP; at the conclusion of the procedure, these surgeons rated the ease of operation and visualization based on the quality of the surgical field, evaluation of the small and large bowel, and surgical difficulty. MBP was not associated with any measured outcome, including complications, surgical time, and self-assessed ease of operation—although patients reported significantly more discomfort with MBP.⁴

Easing intraoperative colonoscopy

Experts agree that planned or potential intraoperative colonoscopy is a clear indication for adequate bowel preparation.¹⁰ A smaller body of evidence suggests that, when “subtle palpation of the bowel wall” is required, MBP may help the surgeon avoid mistaking a nodule for stool.^5,25

Beyond these examples, routine MBP is not supported by randomized data.

We sorely need guidelines on MBP

Like many general and colorectal surgeons, many gynecologists still use MBP. A 2011 survey of Canadian gynecologic oncologists reported that 47% still routinely order MBP, although 77% of surgeons acknowledged a lack of “good evidence” to support the practice.²⁶ Similarly, although 95% of colorectal surgeons in Michigan in 2011 believed that the data against routine use of MBP was scientifically valid, only 50% agreed that MBP was unnecessary.²⁷ Data from Spain echo these results: 77% of surgeons viewed bowel preparation as useful or very useful.²⁸

The striking contrast between literature and practice merits scrutiny. When the literature demonstrates no need for MBP and a risk of patient harm, why are so many surgeons still electing preoperative MBP for their patients? Reasons listed by gynecologic oncologists in a 2011 survey varied but included a reduction in anastomotic leakage (31%) and improved visualization (37%)—reasons unsupported by the randomized literature. A majority (71%) agreed that guidelines would be helpful in determining the appropriate use of MBP, if any.²⁶ Overall, ACOG has not laid out clear guidelines on the use or avoidance of MBP to support gynecologic surgeons’ decision-making.

MBP is an antiquated practice

The colorectal literature has identified MBP as an antiquated practice without evidence to support its routine use. Therefore, mechanical bowel preparation is likely to be of minimal value for patients undergoing major gynecologic surgery, based on extensive data from randomized trials of planned bowel surgery.²⁹ The role of MBP in laparoscopic, robotic, and vaginal surgery is less clearly defined, although there is no clear evidence to support the use of MBP in any surgical modality except intraoperative colonoscopy. Despite the lack of clear guidance from ACOG, the colorectal and gynecologic literature strongly suggests that MBP does not reduce the risk of SSI or intraoperative or postoperative complications. Nor do surgical ease and visibility appear to be improved with MBP, though the literature in this area is limited.

MBP is not without risk, particularly for elderly patients who have medical comorbidities. Without clearly established benefits, we recommend that you strongly consider these randomized data and limit—or even eliminate—the use of MBP for major abdominal procedures in your practice.

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