Uterosacral ligament suspension and sacrospinous ligament fixation are commonly performed native tissue surgical procedures for pelvic organ prolapse in the apical compartment.1,2 Risk factors for recurrent pelvic organ prolapse include prior hysterectomy, previous pelvic reconstructive surgery,3 and a native tissue approach.4 Unfortunately, the pathophysiology of recurrent prolapse is not well-understood and the aforementioned risk factors are not modifiable.
Several studies suggest that a widened preoperative genital hiatus is also a risk factor for prolapse recurrence.5–9 However, we do not clearly understand whether surgical reduction of the genital hiatus size helps to minimize prolapse recurrence and to what degree the genital hiatus should be reduced during surgical repair. It is unclear if a universally performed posterior repair or perineorrhaphy is necessary in women with a widened preoperative genital hiatus or if there is a “goal” genital hiatus that would decrease an individual's risk of failure after a native tissue vaginal repair. The decision on whether to perform a posterior repair or perineorrhaphy is not standardized and it is important that clinicians have improved tools to decide who may benefit from this additional procedure.
The primary aim of this study is to compare anatomic outcomes after native tissue vaginal vault suspension with either uterosacral ligament suspension or sacrospinous ligament fixation at medium term among women categorized by their preoperative and 6-week postoperative genital hiatus size. We hypothesized that women with a persistently wide genital hiatus of 4 cm or greater will have the highest risk of anatomic failure after native tissue vaginal vault suspension.
MATERIALS AND METHODS
After approval from the institutional review board at Duke University Medical Center (# Pro00075311), we performed a retrospective cohort study of women undergoing native tissue vaginal vault suspension with uterosacral ligament suspension or sacrospinous ligament fixation for either uterine prolapse or posthysterectomy vaginal vault prolapse. We grouped uterosacral ligament suspension and sacrospinous ligament fixation procedures together for our analysis based on similar anatomic and functional outcomes of the two procedures noted in the OPTIMAL trial.2 Women were identified by their Current Procedural Terminology code for these procedures (57282 or 57283). Our study population included women undergoing surgery within the division of female pelvic medicine and reconstructive surgery at a single academic medical center from January 1, 2005, to August 16, 2015. Women were included if they had full pelvic organ prolapse quantification system (POP-Q) examination information from a preoperative and 6-week postoperative visit along with at least one subsequent visit at medium term, defined as any time point between 3 months and 2 years after surgery. All pertinent POP-Q measurements were performed during Valsalva. Women were excluded if their surgery was performed by a health care provider in another division (urologist or general obstetrician–gynecologist), if the repair was mesh- or graft-augmented, or if the woman was missing any POP-Q examination information at any of the three time points of interest. We compared anatomic outcomes at medium term in three groups: 1) women with a wide genital hiatus preoperatively and 6 weeks postoperatively (persistently wide cohort), 2) women with a wide genital hiatus preoperatively but normal genital hiatus 6 weeks postoperatively (improved cohort), and 3) women with a normal genital hiatus preoperatively and 6 weeks postoperatively (stably normal cohort). We defined a wide genital hiatus as 4 cm or greater and a normal genital hiatus as less than 4 cm. We defined preoperative advanced prolapse as stage 3 prolapse or greater in at least one compartment. Our primary outcome was composite anatomic failure at medium term, defined as either recurrent prolapse in any vaginal compartment beyond the hymen (POP-Q point Ba, Bp, or C greater than 0) or retreatment for prolapse with surgery or pessary. We combined posterior colporrhaphy and perineorrhaphy into one variable for the analysis, because very few patients received only a posterior colporrhaphy without a perineorrhaphy.
Electronic health records were reviewed and data collected with regard to demographics, medical and surgical history, concurrent procedures, perioperative complications, POP-Q examinations, and length of follow-up. All data were abstracted by manual chart review by members of the study team and included a detailed review of operative reports as well as all postoperative visits recorded in the electronic health record. Data were extracted from the medical record through a double-entry process.
Demographic, perioperative, and postoperative data were compared among the three groups. Data analysis was performed using IBM SPSS Statistics 24.0. Continuous variables were analyzed using one-way analysis of variance with pairwise post hoc analysis as appropriate. Categorical variables were analyzed using χ2 tests or Fisher exact tests as appropriate. Bivariate analyses were conducted to determine relationships between variables and risk of failure followed by multivariable logistic regression to adjust for potential confounders.
For our full regression model covariates, we initially considered known a priori risk factors for prolapse, significantly different baseline characteristics between our two cohorts, and variables that were significantly different among groups in bivariate analyses. We then conducted a stepwise variable selection procedure to identify the model that best fit the data. To estimate the incremental odds of failure for each genital hiatus group, we performed two final regression models. The first model included the improved genital hiatus group as the reference group with the following covariates: concomitant anterior repair, concomitant posterior repair or perineorrhaphy, prior hysterectomy, advanced preoperative prolapse, and permanent suture type for suspension procedure. The second model used the stably normal group as the reference group with the same covariates. We recognize that genital hiatus is a continuous variable that we dichotomized for our groups. Therefore, we performed a third logistic regression model that included the baseline genital hiatus as a predictor and genital hiatus change score (preoperative genital hiatus minus postoperative genital hiatus) as a covariate. Additional covariates in this third model were concomitant posterior colporrhaphy, concomitant anterior colporrhaphy, prior hysterectomy, advanced preoperative prolapse, and suture type. For all data analyses, a P value of <.05 was considered statistically significant.
A total of 295 patients underwent a native tissue vaginal vault suspension with at least one medium-term postoperative visit during the study time period. Thirty-five patients were excluded as a result of exclusion criteria (Fig. 1). Therefore, our final study population consisted of 260 women with mean body mass index (BMI, calculated as weight (kg)/[height (m)]2) of 27.6±5.3 and mean age of 63.3±9.7 years. Of the 258 women who reported race, 222 (85.4%) were white; 170 of 260 (65.4%) had advanced preoperative prolapse and 65 of 260 (25.0%) had a prior hysterectomy. Mean follow-up time was 349±155.2 days. Overall, 92 patients in the study population had either a posterior colporrhaphy or perineorrhaphy. Eighty-one (88%) of those patients had a combined posterior repair with perineorrhaphy, 4 of 92 (4.3%) had a perineorrhaphy without concomitant posterior colporrhaphy, and 7 of 92 (7.6%) had only posterior colporrhaphy stitches.
Approximately 15.0% (39/260) of patients in our study had a persistently wide genital hiatus, 60.4% (157/260) were improved, and 24.6% (64/260) were stably normal. Baseline characteristics of the genital hiatus groups are presented in Table 1. There were differences among groups with respect to advanced preoperative prolapse (P<.01), mean BMI (P<.01), and concomitant posterior colporrhaphy or perineorrhaphy (P<.01) (Table 1). There were no differences among groups with respect to parity, age at the time of surgery, or follow-up time. We also noted no difference in age (P=.10), BMI (P=.48), parity (P=.94), advanced preoperative prolapse (P=.69), or concomitant posterior colporrhaphy or perineorrhaphy (P=.82) with regard to route of apical suspension (uterosacral ligament suspension vs sacrospinous ligament fixation). With respect to intraoperative characteristics, there were no differences in concomitant anterior colporrhaphy (P=.79) or hysterectomy (P=.88) among genital hiatus groups. Approximately 45% of the improved group underwent concomitant posterior colporrhaphy or perineorrhaphy compared with 18% in the persistently wide group and 22% in the stably normal group. These differences were statistically significant (P<.01).
Regarding the primary outcome, composite anatomic failure occurred in 50 of 260 (19.2%) women. There was a statistically significant difference in overall composite anatomic failure among the groups (P<.01). Composite anatomic failure was significantly more likely in the persistently wide group (51.3%) compared with the improved group (16.6%, P<.01) and compared with the stably normal group (6.3%, P<.01). These results were consistent when examining all vaginal compartments individually, including anterior, apical, and posterior (Table 2). There was a trend toward more reoperations in the persistently wide group (17.9%) compared with the improved (8.3%) and stably normal groups (4.7%), but this trend did not reach statistical significance (P=.07).
We performed additional bivariate analyses and found no differences in anatomic failure in patients with advanced preoperative prolapse (P=.09), patients with prior hysterectomy (P=.36), diabetes (P=.64), route of vault suspension (uterosacral ligament suspension vs sacrospinous ligament fixation, P=.90), or use of permanent compared with absorbable suspension suture (P=.45). There was also no difference in anatomic failure among patients undergoing a primary compared with a secondary prolapse repair (P=.16). Notably, patients undergoing posterior colporrhaphy or perineorrhaphy were less likely to have composite anatomic failure in bivariate analysis (P=.03). We also performed a Kaplan-Meier survival analysis (Fig. 2). Based on the log-rank test, we determined the shortest time to anatomic failure was in the persistently wide group (P<.01; Fig. 2).
Regarding the two baseline logistic regression models (the first model with the improved group as a reference (Table 3) and the second model with the stably normal group as the reference (Table 4), the persistently wide genital hiatus cohort was associated with a 4.4-fold increased odds of composite failure (adjusted odds ratio [OR] 4.41, 95% CI 1.99–9.76, P<.01; Table 3) compared with the improved genital hiatus cohort and a 15.8-fold increased odds compared with the stably normal genital hiatus cohort (adjusted OR 15.8, 95% CI 4.66–53.57, P<.01; Table 4). Notably, BMI was significantly different between certain groups in bivariate analysis, but was not included in the final logistic regression models because it was no longer statistically significant. In the third logistic regression model in which baseline genital hiatus score (continuous variable) was used as a predictor with genital hiatus change score as a covariate, for every 1-cm increase in the baseline genital hiatus, there was a 2.6-fold increased odds of anatomic failure (adjusted OR 2.64, 95% CI 1.72–4.03, P<.01; Table 5). Moreover, for every 1-cm change in genital hiatus compared with baseline, there was a 56% reduction in the odds of composite anatomic failure (adjusted OR 0.56, 95% CI 0.37–0.86, P<.01). For each of the three logistic regression models, one case was missing for a final n of 259 cases included in the analysis.
Women with a persistently wide genital hiatus 6 weeks after native tissue vaginal vault suspension were at significantly higher odds of anatomic failure at medium term compared with women with an improved or stably normal genital hiatus. Women presenting with a normal genital hiatus (less than 4 cm) who remain stably normal after surgery have the lowest odds of anatomic failure. Furthermore, regression models demonstrate a higher odds of anatomic failure with every centimeter increase in preoperative genital hiatus and a decreased odds of failure for each incremental centimeter of genital hiatus reduction.
The main strengths of our study include a large, well-characterized study population with consistent surgical techniques used over a 10-year study period. Importantly, we present a novel categorization of women that takes into account the surgical reduction of a patient's genital hiatus size. This categorization of patients is clinically relevant and we anticipate it will help guide surgical decision-making, specifically regarding when to perform a posterior repair or perineorrhaphy, at the time of native tissue vaginal vault suspension. Finally, we based our primary outcome of anatomic failure on a rigorous definition that is supported in the literature.10
In terms of study limitations, we recognize that our study lacks formal subjective outcomes. However, we considered retreatment for prolapse as a proxy for subjective outcomes and included reoperation in our composite anatomic failure outcome measure. Another limitation of our study is the potential for selection bias, because the decision to add a posterior repair or perineorrhaphy at the time of vault suspension was not standardized among surgeons. We included this variable in a variety of logistic regression models to control for this possible bias. Finally, postoperative genital hiatus measurements taken at the end of surgery may be more clinically relevant compared with 6-week postoperative measurements. For purposes of this study, we chose to use the 6-week postoperative measurement according to the conventional definition,11 which is performed during Valsalva. We assumed that the 6-week postoperative genital hiatus would be consistent with intraoperative measurements, but clearly an immediate postoperative measurement would be useful in future studies.
Our present work expands on prior studies that have investigated the association between genital hiatus size and vaginal prolapse, including several retrospective studies that likely overestimated rates of prolapse recurrence based on liberal pelvic organ prolapse diagnosis.7,8 Lowder et al9 retrospectively studied factors associated with apical support loss and found that a genital hiatus of greater than 3.75 cm was highly predictive of vaginal apical prolapse. Our study expands on these investigations by confirming that a widened genital hiatus is associated with risk of prolapse recurrence after surgery and further demonstrates that surgical correction of a widened genital hiatus may mitigate recurrence risk.
In our study population, women with a genital hiatus less than 4 cm (stably normal) had lower BMI, less advanced prolapse, and the least risk of prolapse recurrence compared with the improved or persistently wide groups. Thus, women in this group may comprise a different subpopulation with less preoperative injury to the pelvic floor and therefore greater likelihood of successful repair. However, with the exception of some minor differences in BMI (Table 1), the women in our improved and persistently wide groups were generally similar. Therefore, the comparisons between these groups, particularly with regard to the effect of surgical change in genital hiatus, are particularly intriguing. These data prompt the question of whether surgical reduction of a wide genital hiatus actually minimizes prolapse recurrence or whether narrowing the hiatus simply masks a recurrent prolapse that does not proceed beyond the hymen. Future prospective studies addressing this question that also include validated symptom assessments would be useful. Moreover, the decision to add a posterior colporrhaphy or perineorrhaphy at the time of native tissue vaginal vault suspension should be carefully considered only after appropriate preoperative counseling that includes a discussion of the possible functional sequelae of these procedures, including dyspareunia, pain, and defecatory symptoms.
In conclusion, our data indicate that a persistently wide genital hiatus after native tissue vaginal vault suspension is associated with significantly higher odds of future anatomic failure. Additionally, women in our study who began with a normal genital hiatus preoperatively (stably normal group) had the lowest odds of anatomic failure. These data are important for perioperative counseling and risk stratification. Baseline genital hiatus size itself is not a modifiable risk factor, but surgical reduction of the genital hiatus at the time of uterosacral ligament suspension or sacrospinous ligament fixation should be considered to reduce the risk of prolapse recurrence.
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