According to the most recent population study from the 1999 National Health and Nutrition Examination Survey, approximately 61% of the U.S. population were overweight or obese (body mass index [BMI] more than 25 kg/m2).1 Of these, 34% were overweight with a BMI of 25 to 29.9 kg/m2, and 27% were classified as obese with a BMI equal to or greater than 30 kg/m2.1 The prevalence of morbid obesity (BMI more than 40) in American adults (aged older than 18 years) has rapidly increased from 0.78% in 1990 to 2.2% in the year 2000.2
It has been shown that morbidity rates in obese patients who underwent elective general surgery were not much different from those of the nonobese.3 In the obese group, however, the incidence of wound infections after open surgery was significantly increased.3,4 Wound complications have been one of the major concerns in obese women who undergo abdominal hysterectomy as well. Because vaginal hysterectomy eliminates an abdominal wound, and therefore wound complications, entirely, it is intuitive to suggest that vaginal approach may be more favorable for obese women. Previously, there have been some efforts to assess the effect of obesity on hysterectomy outcomes. However, these retrospective studies only compared the obese and nonobese groups for either abdominal or vaginal hysterectomies, and produced somewhat conflicting information due to confounding factors.4–7 Moreover, they used weight cutoffs for categorizations, instead of BMI criteria, disregarding the effects of height.4,5 Our aim in this study was to assess the operative and postoperative outcomes of abdominal and vaginal hysterectomy in obese women, with the modern definition based on BMI.
MATERIALS AND METHODS
In a retrospective, cohort study, we reviewed the hospital records of all women with a BMI of 30 kg/m2 or more who underwent simple hysterectomy for benign gynecologic conditions at Temple University Hospital from January 1997 to December 2002. Procedures that were combined with other major pelvic and abdominal surgery were excluded. Minor concomitant procedures, such as oophorectomy, ovarian cystectomy, salpingectomy, appendectomy, and cystoscopy, were included in our analysis. Obese women who underwent abdominal hysterectomy were compared with those whose hysterectomies were completed vaginally without any laparoscopic or abdominal entry. Antibiotic prophylaxis and overnight indwelling urinary catheterization were standard for all the cases.
Age, race, gravidity, parity, comorbid medical conditions, indications for hysterectomy and previous abdominal or pelvic surgeries were analyzed. We also evaluated perioperative complications such as postoperative febrile morbidity, ileus, bowel and urinary tract injury, wound complications, urinary tract infection, urinary retention, thromboembolic events, postoperative hemorrhage, and blood transfusion. Parameters such as change of hemoglobin concentration within 24 hours of surgery, operative time, and length of hospital stay were compared as well.
Previous pelvic surgeries were categorized as uterine, adnexal, and bowel surgery that can potentially increase the risk of complications due to adhesions during hysterectomy. When assigning the primary indication for the hysterectomy, we occasionally had to use our medical judgment using the available information from the charts, because there were some patients with 2 or more diagnoses listed. For example, the indication for surgery was assigned as uterine leiomyoma if the patient was complaining of pelvic pain and menometrorrhagia due to uterine leiomyomata.
Febrile morbidity was defined as 2 oral temperature measurements of 38.0°C and greater occurring at least 6 hours apart and at least 24 hours after the procedure. Ileus was diagnosed when bowel dysfunction, delaying oral intake, causing nausea, vomiting, and abdominal distention or decreased bowel sounds or both, resolved with conservative management. Urinary tract infection was diagnosed by growth of at least 100,000 colony-forming units of a urinary tract pathogen per milliliter in a culture of a midstream urine sample. Any specimen containing high colony counts with more than 1 species of bacterium in asymptomatic patients was considered contaminated. Postoperative hemorrhage diagnosis was made when there was clinical and laboratory signs of rapid blood loss that required transfusion or reoperation after the completion of the hysterectomy. Any wound complication that required early removal of staples or stitches and exploration of the incision was included in the wound complication category. Any damage to ureter or bladder was combined as urinary tract injury. Last, perioperative hemoglobin change was calculated by finding the difference between the hemoglobin level on the first postoperative day and the one taken as a part of preadmission assessment.
The study was approved by the institutional review board. Software by SAS (Cary, NC) was used for statistical analysis. Comparisons were done by means of frequency tables and Fisher exact test for categorical variables, and independent t tests for the continuous ones. A P value of less than .05 was used for assignment of significance. Univariate logistic regression analysis was used to estimate the relationship of the perioperative outcome measures with the hysterectomy route. The odds ratio and the 95% confidence interval were calculated for each discrete variable. The statistically significant variables were then combined in a multivariate stepwise logistic regression to ascertain that each variable was indeed statistically significant, independent of the other factors.
During the study period there was a total of 899 women who underwent abdominal or vaginal hysterectomy for benign gynecologic conditions with complete medical records. The total number of women with a BMI of 30 kg/m2 or greater was 369 (41%). Of these, 189 (51.2%) of the procedures were performed abdominally and 180 (48.8%) were completed vaginally.
Although the mean age, BMI, and race distribution did not differ between the groups, women who underwent vaginal hysterectomy had higher mean gravidity, parity, and lower uterine weight (Table 1). Uterine leiomyomata were the primary indication in both groups (Table 2). In women with prolapse, it has been noted that primarily the vaginal approach was preferred; 28 of 29 (96.6%) women with prolapse underwent vaginal hysterectomy. Hysterectomies for chronic pelvic pain and pelvic masses are performed more frequently abdominally, 83.3% and 86.4%, respectively. No difference was noted between the groups with respect to comorbid conditions and previous abdominal or pelvic surgeries (Table 3).
After controlling for all the significantly different variables, lower incidences in favor of vaginal hysterectomy were noted for postoperative fever (odds ratio [OR] 0.22, 95% confidence interval [CI] 0.12–0.39), ileus (OR 0.21, 95% CI 0.06–0.75), and urinary tract infection (OR 0.21, 95% CI 0.06–0.75). Seven women (3.7%) who underwent abdominal hysterectomy developed wound infections during their hospital stay compared with none in the vaginal hysterectomy group. Vaginal hysterectomies resulted in a significantly shorter operative time and hospital stay but similar perioperative hemoglobin concentration change. Bleeding requiring transfusion did not differ between the groups (Table 4).
Although not statistically significant, 2 (1.1%) of the vaginal hysterectomy patients suffered from postoperative hemorrhage (Table 4). One of these women had to be taken back to the operating room. An exploratory laparotomy was performed; bleeding from 1 of the pedicles was identified and stopped. The bleeding in the other patient was managed conservatively with success.
Our results showed a lower incidence in fever, ileus, urinary tract infection, and wound complications after vaginal hysterectomy when compared with abdominal hysterectomy in obese women. In addition, vaginal approach in obese women resulted in shorter operative time and required shorter hospital stay compared with the abdominal procedure.
Pitkin4,5 studied the effect of obesity in abdominal and vaginal hysterectomy. In his first study focusing on abdominal hysterectomy only, he compared 300 women weighing at least 200 lb with a matched control group of women weighing less than 200 lb. He found that heavy women had significantly increased operative time, blood loss with consecutive transfusion, and a striking 7-fold increase in wound complications, which was mostly responsible for a doubling of postoperative fever and a tripling of length of hospital stay.4 In the following year, using the same weight cutoff, Pitkin reported his findings for vaginal hysterectomy, with 108 women in each group. Postoperative fever and length of hospitalization did not reveal any statistically significant difference between the groups. However operative time and blood loss were increased in the obese group, and this was attributed to the fact that these women underwent significantly more concomitant anterior or posterior repair or both than the normal weight women (P < .01).5 Pitkin's conclusion based on these 2 studies was that obesity increased the morbidity of abdominal hysterectomy but not that of vaginal hysterectomy. These studies were limited by their retrospective design, omission of the effect of height, and the presence of various confounding factors, including pelvic floor repairs. Clearly, comparison between the patients from his first study, who underwent abdominal hysterectomies, and those of the second, who had the vaginal approach, would not be ideal scientifically, because this would be a historical comparison. Later, in 1990, Pratt and Daikoku6 made one more attempt to assess the effect of vaginal hysterectomy by comparing normal weight, overweight, and obese women using the ideal body weight corrected for height. At least 63% of each comparison group in their study had pelvic relaxation, and 72% of all patients needed pelvic floor repairs. Although they did not use any significance tests for statistical analyses, they somehow concluded “...obesity per se caused few problems during and after vaginal hysterectomy.” Practice styles, surgical techniques, and anesthesia and postanesthesia care have changed during the decades since these studies were published. Certainly, the modern definition of obesity with BMI cutoffs, which minimizes the effect of height, is necessary to apply this information to clinical use today. Last, we have not been able to find any scientific report comparing abdominal and vaginal routes for hysterectomy in obese women.
By excluding the women who required concomitant pelvic floor repair, we were able to eliminate the potential confounding effects of additional surgery. Even though we had an adequately large sample size for most comparisons, a larger group could have improved the power of the study for statistical analyses of rare complications. We included every obese woman who underwent abdominal or vaginal hysterectomy during the study period but not both approaches. This is why we did not take 5 women whose surgeries were started vaginally, then converted to laparotomy for difficult access or bleeding. It would be very hard to attribute any complication, prolonged operative time, or hospital stay to either route of hysterectomy.
Because this is a retrospective study, selection and reporting biases cannot be completely eliminated. Gynecologists may choose abdominal route when they anticipate complications, especially for women with chronic pelvic pain, suspected endometriosis, pelvic infection, and enlarged uterus. Because this could affect the outcomes, we tried to adjust and account for these factors.
We regret that we did not have access to the postoperative outpatient records of the entire study population, and late-occurring complications could not be analyzed in this article. Due to short hospitalization, it is likely that we missed some complications, especially wound problems that possibly occurred after discharge from the hospital. Despite this, 7 of 189 women (3.7%) who underwent abdominal hysterectomy developed wound infection during their hospital stay. Wound complications have been shown to be the major concern in obese patients after abdominal hysterectomy resulting in febrile morbidity and prolonged hospitalization.4
Our study suggests that vaginal approach should be preferred for hysterectomies in obese patients due to significant decrease in postoperative febrile morbidity, ileus, urinary tract infection, operating time, and length of hospitalization. Larger prospective multicenter studies are necessary to have more precise assessment about the effects of hysterectomy route in obese women.