Background
Recognition and assessment of apical vaginal support defects remains a significant challenge in the evaluation and management of prolapse. There are several reasons that this is likely: (1) Although the Pelvic Organ Prolapse-Quantification examination is the standard prolapse staging system used in the Female Pelvic Medicine and Reconstructive Surgery field for reporting outcomes, this assessment is not used commonly in clinical care outside the subspecialty; (2) no clinically useful and accepted definition of apical support loss exists, and (3) no consensus or guidelines address the degree of apical support loss at which an apical support procedure should be performed routinely.
Objective
The purpose of this study was to identify a simple screening measure for significant loss of apical vaginal support.
Study Design
This was an analysis of women with Pelvic Organ Prolapse-Quantification stage 0-IV prolapse. Women with total vaginal length of ≥7 cm were included to define a population with “normal” vaginal length. Univariable and linear regression analyses were used to identify Pelvic Organ Prolapse-Quantification points that were associated with 3 definitions of apical support loss: the International Consultation on Incontinence, the Pelvic Floor Disorders Network revised eCARE, and a Pelvic Organ Prolapse-Quantification point C cut-point developed by Dietz et al. Linear and logistic regression models were created to assess predictors of overall apical support loss according to these definitions. Receiver operator characteristic curves were generated to determine test characteristics of the predictor variables and the areas under the curves were calculated.
Results
Of 469 women, 453 women met the inclusion criterion. The median Pelvic Organ Prolapse-Quantification stage was III, and the median leading edge of prolapse was +2 cm (range, –3 to 12 cm). By stage of prolapse (0-IV), mean genital hiatus size (genital hiatus; mid urethra to posterior fourchette) increased: 2.0 ± 0.5, 3.0 ± 0.5, 4.0 ± 1.0, 5.0 ± 1.0, and 6.5 ± 1.5 cm, respectively ( P < .01). Pelvic Organ Prolapse-Quantification points B anterior, B posterior, and genital hiatus had moderate-to-strong associations with overall apical support loss and all definitions of apical support loss. Linear regression models that predict overall apical support loss and logistic regression models predict apical support loss as defined by International Continence Society, eCARE, and the point C; cut-point definitions were fit with points B anterior, B posterior, and genital hiatus; these 3 points explained more than one-half of the model variance. Receiver operator characteristic analysis for all definitions of apical support loss found that genital hiatus >3.75 cm was highly predictive of apical support loss (area under the curve, >0.8 in all models).
Conclusions
Increasing genital hiatus size is associated highly with and predictive of apical vaginal support loss. Specifically, the Pelvic Organ Prolapse-Quantification measurement genital hiatus of ≥3.75 cm is highly predictive of apical support loss by all study definitions. This simple measurement can be used to screen for apical support loss and the need for further evaluation of apical vaginal support before planning a hysterectomy or prolapse surgery.
Although the vaginal apex is essential for pelvic organ support, recognition and assessment of apical support defects remains a significant challenge in the evaluation and management of pelvic organ prolapse. The International Consultation on Incontinence states that apical vaginal support, regardless of the presence or absence of the uterus, must be assessed and that the best surgical correction of the anterior and posterior walls may fail unless the apex is supported adequately. Likewise, Eilber et al showed that the reoperation rate for prolapse at 10 years was reduced significantly when a concomitant apical support procedure was performed. However, despite >20 years of evidence regarding the pivotal role of apical support loss in anterior and posterior vaginal wall prolapse, the most frequently performed procedures for prolapse continue to be anterior and/or posterior colporrhaphy without concomitant apical support procedures. The variable was not in the model
Several factors may explain the reason that apical support procedures are performed infrequently concomitantly with anterior and/or posterior vaginal wall repairs. First, although the Pelvic Organ Prolapse-Quantification (POP-Q) examination is the standard prolapse staging system used in the Female Pelvic Medicine and Reconstructive Surgery field for reporting outcomes, this assessment is not used commonly in clinical care outside the subspecialty. One of the primary advancements of the POP-Q was the standardized, independent evaluation of all 3 compartments (anterior, apical, and posterior) of the vagina. Because the POP-Q is not used widely, these 3 compartments may not be assessed routinely and adequately. Also, the POP-Q may not be used commonly by nonspecialists because it has been described as “cumbersome” and “difficult to teach.” )
A second likely explanation is that no clinically useful and accepted definition of apical support loss exists. The currently available definitions are based on point C of the POP-Q. Point C is the distance from the hymen to the cervix or vaginal cuff (herein referred to as the vaginal apex) and is a negative number if the vaginal apex is above the hymen. The International Consultation on Incontinence (ICI) defines apical support loss as the vaginal apex descending to a point 2 cm lower than the total vaginal length (TVL; eg, C > TVL –2 cm). However, this definition has come under some scrutiny as being too stringent. In a recent publication of the 7-year outcomes of the National Institutes of Health–Pelvic Floor Disorders Network extended Colpopexy and Urinary Reduction Efforts (eCARE) study, the authors revised the definition of apical support loss to apical descent more than one third TVL.
Finally, no consensus or guidelines address the degree of apical support loss at which an apical support procedure should be performed routinely. Thus, it is not surprising that apical support procedures continue to be underused. The objective of this study was to determine whether clinically significant apical support loss, as defined by 3 methods, could be predicted with a single or simple combination of POP-Q points so that apical support loss could be screened for more easily. Clinically significant apical support loss was defined by ICI, the eCARE Study, and a POP-Q point C cut point that was identified recently by Dietz and Mann to be associated with symptoms of pelvic organ prolapse.
Materials and Methods
This is a secondary analysis of a single-institution database that was developed from 2 nonoverlapping studies. The first study was designed to assess pelvic floor symptoms in women with POP-Q stages I-IV prolapse. In that study, women presenting for evaluation of pelvic floor disorders were recruited from a tertiary urogynecology practice between July 2003 and September 2005. The second study was designed to evaluate body image in women who undergo reconstructive surgery for prolapse and had a control arm of women without symptomatic prolapse (POP-Q stage ≤ I and answering “no” to Pelvic Floor Disorders Inventory [PFDI] questions 4 and 5). Women were recruited from an academic general gynecology practice and a tertiary urogynecology practice from December 2005 to January 2009. Design and results of these studies have been described previously. In both studies, women underwent the POP-Q examination as part of routine clinical care and completed a research questionnaire packet that included biodemographics, past medical and surgical information, and general and disease-specific health-related quality of life and symptom questionnaires, which included the PFDI. Given the design of the original studies, populations, sample sizes, and inclusion of all stages of pelvic organ support, this combined dataset was appropriate for our study objective and analyses. Although the parent studies were completed in 2005 and 2009, the nature of the data being analyzed (the POP-Q) and the disease process (prolapse) have not changed since those dates. The combination of the 2 databases allowed a dataset with a complete range of pelvic organ support (POP-Q stage 0-IV). The University of Pittsburgh Institutional Review Board approved both the original studies and this study. The use of the deidentified databases for this analysis was considered exempt (institutional review board, # PRO15080063).
For this analysis, we selected subjects with a TVL ≥7 cm (n = 450), which we define as a “normal” vaginal length. Dichotomous variables (“0” denotes apical support and “1” denotes apical support loss) were created for 3 definitions of apical support loss: (1) For the ICI definition, we defined point C < TVL –2 cm = 0, and point C ≥ TVL –2 cm = 1. (2) For the eCARE definition, we defined point C less than one third TVL = 0, and point C more than or equal to one third TVL = 1. (3) On the basis of work by Dietz and Mann who found that a POP-Q point C ≥ –5 cm was associated with significant overall prolapse symptoms, we defined point C < –5 cm = 0 and point C ≥ –5 cm = 1. This variable will be referred to as “point C –5 cm.” To allow for applicability of this point C cut-point to different vaginal lengths within the sample, we calculated a variable called the point C:total vaginal length (C:TVL) ratio. The C:TVL cut-point was calculated by dividing the point C cut-point of –5 cm by 9 cm, according to literature-based reports of average vaginal length. (3) Thus, we defined C:TVL < –0.56 = 0, and C:TVL ≥ –0.56 = 1. We evaluated both the point C –5cm variable and the C:TVL –0.56 cut-point values.
All analyses were performed in SPSS statistical software (version 22; IBM Corporation, Armonk, NY). Descriptive statistics for the study sample are reported as mean ± standard deviation (or median with interquartile range) for continuous variables and frequency with percent for categoric variables. The Kolmogorov-Smirnov test and visual assessment of histograms were used to determine whether the distributions of continuous variables were distributed normally. Spearman’s Correlation was used to determine univariable associations between POP-Q points, definitions of apical support loss, and biodemographic information. Explanatory variables that were examined were all 9 POP-Q points (C [cervix or cuff], genital hiatus (GH), perineal body (PB), point D, Aa, Ba, Ap, Bp, TVL), leading edge of prolapse (centimeters relative to hymen), age, ethnicity, body mass index, and hysterectomy (no/yes). All POP-Q point measurements were obtained as originally described during maximum valsalva, except TVL, by Bump et al. To determine whether overall apical support loss (POP-Q point C) could be predicted mathematically and to assess how much variance was accounted for by the explanatory variables selected by the use of Spearman’s Correlation, we created multivariable linear regression models using POP-Q point C as the dependent variable. The models were created in a stepwise fashion and confirmed with a backward fitting linear regression model. To determine whether apical support loss as defined by ICI, eCARE, point C –5 cm, and C:TVL –0.56 definitions could be predicted mathematically, we created multivariable logistic regression models for each definition. The models were created in forward logistic fashion and confirmed with backward logistic models.
Finally, receiver operator characteristic (ROC) curves were calculated for each definition of apical support loss vs predictor variables. The area under the ROC curve (AUC) was calculated as a summary measure of predictive performance of the model. We then used the details tables that were supplied in the ROC output to determine the sensitivity and specificity of the model. The optimal cut-off for the explanatory variables was generated by calculation of the Youden Index that maximized the vertical distance from the line equality to the point (x, y) on the ROC curve. The Youden Index measures the effectiveness of a diagnostic marker and enables the selection of an optimal threshold value (or cutoff point) for the marker. The index ranges between 0 and 1, with values close to 1 that indicate high diagnostic effectiveness of the marker and values close to 0 that indicate limited effectiveness. For all analyses, a probability value of < .05 was considered statistically significant.
Results
From the database, 453 of 462 women met the inclusion criterion (TVL ≥ 7 cm) for this analysis. Descriptive statistics describing relevant biodemographic, surgical history; prolapse-related data are presented in Table 1 . Apical support loss by each definition in this population was as follows: (1) ICI, 366 (80.8%), (2) eCARE,327 (72.2%), (3) point C ≥ –5 cm, 306 (67.5%), and (4) C:TVL ≥ –0.56, 269 (65.3%).
| Characteristic | Measurement |
|---|---|
| Age, y a | 60.5 ± 11.7 |
| Body mass index, kg/m 2 a | 28.7 ± 6.5 |
| Race, n (%) | |
| White | 418 (92.3) |
| Black | 15 (3.3) |
| Other | 9 (2.6) |
| Not reported | 8 (1.8) |
| Hysterectomy, n (%) | 216 (47.7) |
| Pelvic Organ Prolapse–Quantification stage, n (%) | |
| 0 | 23 (5.1) |
| I | 41 (9.1) |
| II | 132 (29.1) |
| III | 226 (49.9) |
| IV | 31 (6.8) |
| Leading edge of prolapse, cm a | +2.0 ± 2.9 (range, –3.0 to 12.0) |
| Compartment of leading edge of prolapse, n (%) | |
| Anterior | 233 (51.4) |
| Apical | 108 (23.8) |
| Posterior | 56 (12.4) |
| Equivalent b | 56 (12.4) |
| Pelvic Organ Prolapse–Quantification, cm a | |
| Aa | +0.0 ± 2.0 |
| Ba | +1.5 ± 3.0 |
| C | –2.5 ± 5.0 |
| D | –4.7 ± 4.8 |
| Total vaginal length | 9.3 ± 1.2 |
| Ap | –1.3 ± 1.5 |
| Bp | –0.3 ± 2.9 |
| Genital hiatus | 4.4 ± 1.6 |
| Perineal body | 3.7 ± 1.1 |
| Answered “Yes” to Pelvic Floor Disorders Inventory question #4: “Do you usually have a sensation of bulging or protrusion from the vaginal area?”, n (%) | 294 (66.1) |
| Answered “Yes” to Pelvic Floor Disorders Inventory question #5 “Do you usually have a bulge or something falling out that you can see or feel in the vaginal area?”, n (%) | 291 (65.1) |
a Data are given as mean ± standard deviation
As an initial assessment of “symptomatic” prolapse in this population, the PFDI question #5 “Do you usually have a bulge or something falling out that you can see or feel in the vaginal area?” was analyzed by the dichotomous definitions of apical support loss. In this population, 65.1% (291 women) answered “Yes.” For the ICI, eCARE, point C ≥ –5 cm, and C:TVL ≥ –0.56 definitions of apical support loss, 62.2% (278 women), 58.4% (261 women), 56.8% (254 women), and 54.1% (242 women), respectively, answered “Yes” and had apical support loss by study definitions.
Next, we performed bivariate analyses of POP-Q variables (points Aa, Ba, Ap, Bp, GH, and PB) that might be used to predict overall apical support loss (POP-Q point C) and apical support loss defined by the ICI, eCARE, point C –5 cm, and C:TVL –0.56 definitions. POP-Q points Aa, Ba, Bp, and GH had moderate-to-strong associations with overall apical support loss (POP-Q point C; Table 2 ). POP-Q points Aa, Ba, and GH had moderate-to-strong associations with all definitions of apical support loss, whereas Bp also had moderate association with only 2 definitions: point C –5 cm and C:TVL –0.56 ( Table 2 ). We calculated mean GH and point C as continuous variables by POP-Q stage and found that both increase significantly by POP-Q stage ( Table 3 ).
| Variable | Correlation coefficient | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Aa | P value | Ba | P value | Ap | P value | Bp | P value | Genital hiatus | P value | Perineal body | P value | |
| Point C (continuous) | .386 | < .001 | .746 | < .001 | .277 | < .001 | .640 | < .001 | .593 | < .001 | –.114 | .016 |
| International Consultation on Incontinence a | .400 | < .001 | .505 | < .001 | .218 | < .001 | .297 | < .001 | .484 | < .001 | .044 | .351 |
| Extended Colpopexy and Urinary Reduction Efforts study a | .381 | < .001 | .534 | < .001 | .218 | < .001 | .328 | < .001 | .523 | < .001 | .023 | .633 |
| Point C -5 cm a | .419 | < .001 | .588 | < .001 | .209 | < .001 | .342 | < .001 | .505 | < .001 | –.018 | .711 |
| Point C:total vaginal length –0.56 | .348 | < .001 | .507 | < .001 | .245 | < .001 | .352 | < .001 | .458 | < .001 | .008 | .847 |
| Pelvic Organ Prolapse–Quantification stage | Point C, cm | Genital hiatus, cm |
|---|---|---|
| 0 | –8.0 ± 1.0 | 1.9 ± 1.0 |
| I | –7.5 ± 1.4 | 2.9 ± 0.7 |
| II | –5.2 ± 2.2 | 3.8 ± 1.1 |
| III | –0.7 ± 4.1 | 5.0 ± 1.3 |
| IV | 7.2 ± 2.7 | 6.5 ± 1.7 |
| r -squared | .489 | .424 |
To assess how well the POP-Q measurements (independent variables) predicted overall apical support loss (dependent variables POP-Q point C and C:TVL ratio as a continuous measurements), we created linear regression models that also included biodemographic variables that included age, body mass index, and hysterectomy (no/yes). For POP-Q point C and C:TVL ratio, the following were predictive: POP-Q points Ba, Bp, and GH, and hysterectomy (no/yes; Table 4 ).
| Variable | Point C | Point C:total vaginal length ratio |
|---|---|---|
| β | β | |
| Point Ba | 0.851 a | 0.088 a |
| Point Bp | 0.630 a | 0.067 a |
| Hysterectomy status (Yes-No) | –1.248 a | –0.157 a |
| Genital hiatus | 0.240 b | 0.031 b |
| r -squared | 0.674 | 0.662 |
We also created logistic regression models to assess how well the independent variables predicted apical support loss. For the ICI, eCARE, and point C –5 cm definitions, age and POP-Q points Ba and GH were highly predictive of apical support loss; for C:TVL –0.56 definition, the POP-Q points Ba and GH were highly predictive of apical support loss ( Table 5 ).
| Variable | International Consultation on Incontinence | Extended Colpopexy and Urinary Reduction Efforts study (revised) | Point C –5 cm | Point C:total vaginal length –0.56 cm | ||||
|---|---|---|---|---|---|---|---|---|
| Exp(B) | 95% Confidence interval | Exp(B) | 95% Confidence interval | Exp(B) | 95% Confidence interval | Exp(B) | 95% Confidence interval | |
| Ba | 1.737 a | 1.419–2.125 | 1.520 a | 1.309–1.766 | 1.719 a | 1.481–1.995 | 1.633 a | 1.427–1.867 |
| Genital hiatus | 2.339 a | 1.673–3.272 | 2.337 a | 1.756–3.109 | 1.774 a | 1.371–2.296 | 1.796 a | 1.407–2.292 |
| Age | 1.039 b | 1.009–1.070 | Variable not in model | Variable not in model | 1.024 b | 1.001–1.047 | Variable not in model | Variable not in model |
| r -square | 0.558 | 0.520 | 0.548 | 0.516 | ||||
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