Pelvic organ prolapse is a prevalent condition affecting one in every 10 women in the United States.1 Between 1976 and 2006, 5 million prolapse procedures were performed in the United States.2 The lifetime risk of prolapse surgery is 11% for symptomatic women with an additional 30% risk of reoperation.3
Mechanical bowel preparation is a common but not a universal practice among surgeons operating in the abdominal or pelvic area. Its practice in gynecologic surgery was originally adopted from colorectal surgery where it was perceived to reduce surgical site infection without clear evidence of its benefit.4 A 2011 Cochrane Review of the use of mechanical bowel preparation for elective colorectal surgery concluded that there is no significant evidence that patients benefit from its use or that of rectal enemas.5 Additionally, patients may experience more side effects with bowel preparation and diet alterations, including gastrointestinal distress, dehydration, and electrolyte disturbances.6
Recent studies demonstrated no advantage to mechanical bowel preparation in laparoscopic gynecologic surgery and reported increased adverse side effects.7–9 Although evidence against routine use in colorectal and laparoscopic gynecologic surgery exists and is changing practice,10,11 many pelvic reconstructive surgeons continue to use some form of preoperative bowel preparation.
Because a paucity of evidence exists for the use of bowel preparation before reconstructive vaginal prolapse surgery, we performed a randomized controlled trial to assess the effect of mechanical bowel preparation on intraoperative surgeon acceptability or assessment of the operative field regarding bowel contents. Secondarily, we evaluated patient satisfaction, associated bowel symptoms, and complications.
MATERIALS AND METHODS
This was a single-blind, randomized trial conducted in women presenting to the Urogynecology Care Clinic at the University of Alabama at Birmingham between January 2011 and August 2012. Eligible participants were women older than 19 years of age scheduled to undergo reconstructive vaginal prolapse surgery to include an apical suspension with posterior compartment repair; other surgical procedures were allowed. Women were excluded if they had a history of a total colectomy, a diagnosis of inflammatory bowel disease, colorectal cancer receiving treatment, or chronic constipation per Rome III guidelines.12 Written informed consent was obtained from all participants in accordance with a research protocol approved by the University of Alabama at Birmingham Institutional Review Board for Human Use.
Eligible women were enrolled and randomized to treatment assignment at the time of their preoperative visit (within 30 days of surgery) by research staff. After obtaining informed consent, baseline characteristics including age, body mass index, medical history, surgical history (specific to abdominal, pelvic, or abdominal and pelvic surgery) were recorded and physical examination conducted. Participants received preoperative counseling and were randomly assigned with a 1:1 ratio to receive mechanical bowel preparation (intervention group) or not (control group). On the day before surgery, verbal and written instructions to the intervention group included 1) intake of a clear liquid diet; 2) self-administration of two separate saline enemas at 4:00 PM and at 6:00 PM, along with 3) nothing by mouth after midnight on the day of surgery. Saline enemas were chosen as the intervention because they are the institutional standard for those surgeons who use a mechanical bowel preparation. Instructions given to the control group included: 1) continuation of a regular diet; and 2) nothing by mouth after midnight on the day of surgery. Participants were asked not to reveal the bowel preparation assignment to the surgeon. Both groups were given written instructions on a high-fiber diet (20–25 g/d) as a guideline to follow postoperatively.
Immediately after surgery, the primary surgeon (four faculty pelvic reconstructive surgeons) completed a self-administered questionnaire assessing the intraoperative surgical field. The surgeon's questionnaire included an overall assessment of bowel cleansing as measured on a 4-point Likert scale (1, excellent; 2, good; 3, fair; 4, poor) based on the presence of gas, fluid, particulate formed stool, or large solid stool by inspection and palpation.6 The primary outcome (surgeon acceptability) was dichotomized as “excellent or good” compared with “fair, poor, or missing.” Other factors such as intraoperative stooling, adequacy of visualization, and difficulty with bowel handling were also evaluated. Perioperative parameters collected included operative time, estimated blood loss, use of preoperative antibiotics, surgical complications (if any), and type(s) of surgical procedures performed.
Secondary outcomes included the patient's overall satisfaction with their preoperative regimen (reflecting patient acceptability) using previously reported standardized questions.6 The overall patients' preoperative satisfaction and experience was assessed with a self-administered questionnaire. A modified patient satisfaction question13 assessed overall satisfaction with the following question: “How satisfied are you with the method used to prepare your bowel for your surgery?” with response options of “completely,” “somewhat,” or “not at all.” Participants were also asked to estimate the percentage of enema completed, if they adhered to the preoperative diet regimen, if they were willing to have the identical bowel preparation in the future, and if they would be willing to try another regimen in the future. Participants used a visual analog, scored from 0 (none) to 4 (distressing), to rate severity of their perioperative bowel symptoms. The 13 bowel symptoms included: trouble taking the enema, abdominal fullness or bloating, sleep loss, fatigue, abdominal cramps, nausea, vomiting, anal irritation, weakness or faint feeling, chest pains, chills, and ease of completing their regimen.
The sample size for the primary outcome assumed a reference rate of 87% for acceptable (excellent or good) bowel preparation as reported by Oliveria et al.6 As reported by Muzii,7 the goal was to detect a 20% difference in rates of acceptable bowel preparation between groups with a two-sided 5% significance level and a power of 80%. A sample size of 70 participants was needed in each group. Assuming a 7% attrition rate, we aimed to recruit 150 patients for this study.
Block randomization was applied using blocks of 10. The allocation sequence was computer-generated and concealed in sequentially numbered, opaque, sealed, and stapled envelopes. Corresponding envelopes were opened only after the enrolled participants completed all baseline assessments and it was time to allocate the intervention. Each participant was provided with the assigned preparation regimen by research staff. Participants assigned to the intervention were not blinded. However, surgeons assessing the primary outcome and data analyst were blinded to the allocation.
χ2 (Fisher's exact as applicable) and t tests were used to compare categorical and continuous variables, respectively, between the intervention and control groups. For data that were not normally distributed, Wilcoxon rank sum tests were used to compare medians. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for surgeons' acceptability and patient satisfaction. The analyses are based on an intention-to-treat approach. Per-protocol analyses were also performed. In sensitivity analyses, missing data for surgeons' acceptability were classified as either all treatment failures and or as all treatment successes to compare the consistency of our findings. Adjustment of P values for multiple comparisons was not performed. A P value of ≤.05 was considered to be significant.
Over 20 months, 150 women were enrolled and randomized: 75 to the bowel preparation and 75 to the control group. A total of 145 (97%) participants completed the study. The study patient flow diagram is shown in Figure 1. Demographic, clinical, and intraoperative characteristics were similar between the two groups (Table 1). Ninety-nine percent of the intervention group and 100% of the participants in the control group received concomitant vaginal apical suspension (P>.05). Concurrent posterior colporrhaphy was performed in 96% and 97% of intervention and control groups, respectively (P=.68). There were no significant differences among concomitant hysterectomy, conversion to laparotomy, estimated blood loss, or operative time between groups (P>.05). With regard to complications, there were no bowel injuries at the time of surgery and no surgical site infectious complications in either group postoperatively.
Eight-four percent (63/75) of women adhered to their treatment assignment (completing greater than 50% of the enema and complying with a clear liquid diet) in the mechanical bowel preparation group compared with 93% (70/75) in the control group. No differences existed in the surgeon's intraoperative acceptability of the bowel preparation regarding bowel contents as it related to the surgical field, rated as “excellent or good,” in 85% (61/72) of the intervention group compared with 90% (66/73) in the control group (OR 0.59, 95% CI 0.21–1.61; P=.30) (Table 2). In a sensitivity analysis, with missing data classified as either all successes or all failures, the results were similar (Table 2). Similarly, in per-protocol analysis, of those completing the study, no significant differences in the primary outcome were noted (data not shown). Surgeons' intraoperative assessment of the rectal vault revealed that there were no differences in the presence of gas or stool between the intervention and the control groups (Table 2). Adequate visualization was similar between groups and there were no differences in intraoperative stooling or difficulty of bowel handling between groups, all P>.05. Of the cases noted to have fair or poor bowel preparation, surgeons' subjective evaluation largely reflected stooling on the field while performing a rectal examination during the procedure or while performing the procedure itself.
Overall, patient satisfaction with their bowel preparation was lower in women randomized to the bowel preparation (66% intervention compared with 94% control group, P<.001) (Table 3). The mechanical bowel preparation group was less likely to report “complete” satisfaction compared with the control group (OR 0.11, 95% CI 0.04–0.35; P<.001). In addition, women who received the mechanical bowel preparation were less likely to repeat a mechanical bowel preparation again. Overall, perioperative bowel symptom severity was low in both groups; however, women in the intervention group were more symptomatic. The highest symptom severity scores were reported for hunger pains (1.09±1.13 compared with 0.27±0.73, P<.001), abdominal cramps or pain (0.99±1.35 compared with 0.35±0.91, P<.001), and abdominal fullness and bloating (0.81±1.08 compared with 0.31±0.77, P<.001) for mechanical bowel preparation compared with control groups, respectively. In addition, three (4%) participants noted it to be “distressing” administering the saline enemas.
Use of a mechanical bowel preparation with clear liquids and saline enemas did not significantly improve surgeons' intraoperative acceptability of the operative field regarding the presence of bowel contents compared with a control group. Importantly, women undergoing a bowel preparation before vaginal prolapse surgery reported decreased satisfaction and increased distressing bowel symptoms, strongly suggesting that a bowel preparation should not be performed routinely in women undergoing reconstructive vaginal prolapse surgery.
Our data are in agreement with a recent Cochrane Review summarizing outcomes of 5,805 patients in randomized trials evaluating mechanical bowel preparation for elective colorectal surgery, where it was concluded that its routine use did not prove beneficial. Specifically, there were no statistically significant differences with regard to leakage of the anastomotic site, mortality rates, peritonitis, need for reoperation, wound infection, and other nonabdominal complications.14 Mechanical bowel preparation outcomes using rectal enemas were also included and there was no significant evidence of patient benefit with their use. Although bowel preparation has continued to be performed before vaginal reconstructive prolapse surgery despite the reported overwhelming lack of benefit demonstrated in the colorectal literature,5 and given the low risk of bowel injury (less than 2%) in vaginal reconstructive surgery, it stands to reason that mechanical bowel preparation would not be of benefit even for this potential complication.
Our conclusions also align with prior level I studies investigating the role of bowel preparation in laparoscopic gynecologic surgery.7,8 Yang and colleagues8 randomized 145 women undergoing advanced gynecologic laparoscopy to receive either oral sodium phosphate solution or single sodium phosphate enema. No differences between groups were noted for the acceptability of the surgical field and the use of oral sodium phosphate resulted in more adverse side effects. Muzii et al7 conducted a single-blind trial randomizing 91 patients undergoing diagnostic or operative laparoscopy for gynecologic indications to oral sodium phosphate or no bowel preparation. Similarly, there were no significant differences noted between the control and intervention groups in terms of intraoperative and postoperative complication rates, operative times, surgical field visualization, or self-reported ease of the procedure. The intervention arm also had more perioperative gastrointestinal symptoms.
Lijol and colleagues15 reported findings in 83 women undergoing laparoscopy for benign gynecologic conditions comparing bowel preparation with a preoperative 7-day minimal residue diet. They found no differences in the surgeons' acceptability of surgical field and participants randomized to bowel preparation reported more bowel symptoms. Won et al9 reported the results of a trial of 308 women scheduled for laparoscopic gynecologic surgery. Participants were randomized to one of three arms: fasting only, minimal residue diet the day before surgery plus fasting after midnight, or minimal residue diet with bowel preparation (oral sodium picosulfate) and fasting. Contrary to these findings, a minimal residue diet plus mechanical bowel preparation provided a better surgical view (P<.01) compared with the other two groups using a visual analog scale. However, when the surgical view was assessed by a verbal descriptor scale (excellent, good, medium, sufficient, poor), no difference existed among groups.
Regarding the use of bowel preparation in reconstructive vaginal prolapse surgery, Estanol et al16 reported results of a trial of 41 women with stage II or greater posterior vaginal wall prolapse randomized to a liquid diet and sodium phosphate enema compared with no intervention. The Bristol Stool Scale was used to characterize intestinal transit times. No significant differences were seen in postoperative colonic transit times between the two groups. Wiebracht et al17 reported results of a prospective trial of 40 participants undergoing transvaginal surgery randomized to receive two preoperative enemas or no enemas. They concluded that preoperative enema before transvaginal surgery provided no benefit or improved surgical exposure.
Our study is strengthened by its robust sample size with adequate power and randomized design. This is a well-characterized surgical cohort undergoing a well-defined operative approach with a minimum of a concomitant apical suspension and posterior repair providing level I evidence investigating the usefulness of preoperative bowel preparation for reconstructive vaginal prolapse surgery. The use of previously published standardized questions for assessment of the surgeons' and patients' experiences further strengthens this study, allowing a similar comparison to other trials in the literature. However, the lack of validation of this instrument is a limitation. Nevertheless, these questions are structured using a standardized visual analog scale or Likert scales commonly used and previously published.6,8,15 The study is also limited by participation of a single site; however, assessments were performed by four experienced, high-volume vaginal surgeons increasing generalizability. Finally, given the multiple comparisons, it is possible that some significant associations arose as a result of chance and may not be clinically significant. In conclusion, routine use of mechanical bowel preparation for reconstructive vaginal prolapse surgery should be reconsidered by all pelvic floor surgeons.
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© 2014 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.
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