Geometric analysis of the urethral-vaginal interface curvature in women with and without stress urinary incontinence: A pilot magnetic resonance imaging study

AIMS

To evaluate differences in the curvature of the urethral-vaginal interface in women with and without stress urinary incontinence (SUI) using geometric morphometric analysis techniques.

METHODS

We conducted a pilot case-control study using magnetic resonance imaging (MRI) scans of 18 women with and without SUI. The urethral-vaginal interface at the level of the mid-urethra was fitted with a second-order polynomial regression. The chord length and chord-to-vertex length of the resulting parabolic curve were used to calculate the arc length and radius of a circular arc fitted to the interface curvature. Demographic characteristics and Pelvic Organ Prolapse Quantification (POP-Q) parameters were collected. Subjects were stratified by those with and without SUI, as well as by those with and without anterior wall prolapse beyond 2 cm proximal to the hymen (Aa > -2 cm).

RESULTS

The radius of the urethral-vaginal interface curvature was not found to be different between subjects with and without SUI (8.8 vs. 9.2 mm, p = 0.53); however, this value was smaller in subjects with Aa > -2 (8.4 vs. 11.9 mm, p = 0.03). The chord length, chord-to-vertex length, and arc length comprising the urethral-vaginal interface curvature were similar between subjects with and without SUI, and between subjects with and without Aa > -2 cm (p > 0.05 for all).

CONCLUSIONS

In this pilot study population, the radius of the urethral-vaginal interface curvature at the mid-urethra was smaller among women with anterior vaginal wall prolapse beyond 2 cm proximal to the hymen. A difference in the urethral-vaginal interface curvature among women with and without SUI was not found.

Mechanisms of hiatus failure in prolapse: a multifaceted evaluation

INTRODUCTION AND HYPOTHESIS

We investigated whether factors influencing pelvic floor hiatal closure are inter-related or independent, hypothesizing that (1) hiatus size is moderately correlated with levator defect, pelvic floor muscle strength, and change in hiatus size with contraction and (2) urogenital hiatus (UGH) and levator hiatus (LH) measures are similar in patients with anterior wall (AW) and posterior wall (PW) prolapse.

METHODS

This cross-sectional case-control study included subjects with AW prolapse (n = 50), PW prolapse (n = 50), and normal support (n = 50). Hiatus measurements and levator defects were assessed on MRI, and vaginal closure force was measured with an instrumented speculum. Pearson correlation coefficients and simple and multivariable linear regression models were performed.

RESULTS

During contraction, LH narrowed 47% more in the PW compared to AW group (p = 0.001). With straining, LH lengthened 34% more in the PW than AW group (p < 0.001). With straining, UGH and LH lengthening was greater by 72% and 44% in those with major compared to no/minor defect (p < 0.001 and p = 0.004). Contraction strength explained, at most, 4% of UGH (r = 0.17) or LH (r = 0.20) shortening during contraction (r = 0.17 and r = 0.20, respectively), indicating that these factors are largely independent. After controlling for prolapse size, resting UGH and levator defect status were associated with straining UGH (p < 0.001, p = 0.004), but muscle strength and resting tone were not.

CONCLUSIONS

Hiatus measures are complex and differ according to prolapse occurrence and type. They are, at best, only weakly correlated with pelvic floor muscle strength and movement during contraction.

A novel measurement of pelvic floor cross-sectional area in older and younger women with and without prolapse

BACKGROUND

An increase in size of the aperture of the pelvis that must be spanned by pelvic floor support structures translates to an increase in the force on these structures. Prior studies have measured the bony dimensions of the pelvis, but the effect of changes in muscle bulk that may affect the size of this area are unknown.

OBJECTIVES

To develop a technique to evaluate the aperture size in the anterior pelvis at the level of the levator ani muscle attachments, and to identify age-related changes in women with and without prolapse.

MATERIALS AND METHODS

This was a technique development and pilot case-control study evaluating pelvic magnetic resonance imaging from 30 primiparous women from the Michigan Pelvic Floor Research Group MRI Data Base: 10 younger women with normal support, 10 older women with prolapse, and 10 older menopausal women without prolapse. Anterior pelvic area measurements were made in a plane that included the bilateral ischial spines and the inferior pubic point, approximating the level of the arcus tendineus fascia pelvis. Measurements of the anterior pelvic area, obturator internus muscles, and interspinous diameter were made by 5 independent raters from the Society of Gynecologic Surgeons Pelvic Anatomy Group who focused on developing pelvic imaging techniques, and evaluating interrater reliability. Demographic characteristics were compared across groups of interest using the Wilcoxon rank sum test, χ2, or Fisher exact test where appropriate. Multiple linear regression models were created to identify independent predictors of anterior pelvic area.

RESULTS

Per the study design, groups differed in age and prolapse stage. There were no differences in race, height, body mass index, gravidity, or parity. Patients with prolapse had a significantly longer interspinous diameter, and more major (>50% of the muscle) levator ani defects when compared to both older and younger women without prolapse. Interrater reliability was high for all measurements (intraclass correlation coefficient = 0.96). The anterior pelvic area (cm2) was significantly larger in older women with prolapse compared to older (60 ± 5.1 vs 53 ± 4.9, P = .004) and younger (60 ± 5.1 vs 52 ± 4.6, P = .001) women with normal support. The younger and older women with normal support did not differ in anterior pelvic area (52 ± 4.6 vs 53 ± 4.9, P = .99). After adjusting for race and body mass index, increased anterior pelvic area was significantly associated with the following: being an older woman with prolapse (β = 6.61 cm2, P = .004), and interspinous diameter (β = 4.52 cm2, P = .004).

CONCLUSION

Older women with prolapse had the largest anterior area, suggesting that the anterior pelvic area is a novel measure to consider when evaluating women with prolapse. Interspinous diameter, and being an older woman with prolapse, were associated with a larger anterior pelvic area. This suggests that reduced obturator internus muscle size with age may not be the primary factor in determining anterior pelvic area, but that pelvic dimensions such as interspinous diameter could play a role. The measurements were highly repeatable. The high intraclass correlation coefficient indicates that all raters were able to successfully learn the imaging software and to perform measurements with high reproducibility.

Levator bowl volume during straining and its relationship to other levator measures

INTRODUCTION AND HYPOTHESIS

This study was aimed at measuring levator ani bowl volume at rest and while straining, comparing women with and without prolapse (controls), and assessing the ability of measures of the mid-sagittal bowl area, levator hiatus (LH), and urogenital hiatus (UGH) to predict bowl volume.

METHODS

Forty MRI scans previously acquired in case-control prolapse studies, including 20 women with prolapse and 20 women without prolapse, of similar age and parity, were selected. 3D models of rest and strain bowl volumes were made using sagittal scans and 3D Slicer®. Mid-sagittal bowl area, UGH, and LH were measured using ImageJ. Data were analyzed using two sample t tests, effect sizes, and Pearson's correlation coefficients at the 0.05 significance level.

RESULTS

Data were acquired in a total of 40 total women. Levator bowl volume at strain had a correlation coefficient of 0.5 with bowl volume at rest. During straining, prolapse subjects had a 53% larger bowl volume than control subjects (254 ± 86 cm³ vs 166 ± 44 cm³, p < 0.001), but at rest, the difference was 34% (138 ± 40 cm³ vs 103 ± 25 cm³, p = 0.002). Effect sizes for all parameters were large (d > 0.75). The strongest correlation with straining bowl volume was mid-sagittal straining bowl area (r = 0.86), followed by LH strain (r = 0.80), then UGH strain (r = 0.76).

CONCLUSIONS

Straining levator bowl volume is substantially different than measures made at rest, with only a quarter of straining values explained by resting measurements. The bowl area at strain is the best 2D measurement estimating bowl volume and explains 74% of straining bowl volume.

Documenting pessary offer prior to hysterectomy for management of pelvic organ prolapse

OBJECTIVES

To (1) determine the proportion of hysterectomy cases with documentation of pessary counseling prior to prolapse surgery and (2) identify variables associated with women offered a pessary.

STUDY DESIGN

The Michigan Surgical Quality Collaborative (MSQC) is a hysterectomy improvement initiative. Hysterectomies from 2013 to 2015 in which prolapse was the principal diagnosis were included. "Pessary offer" was defined as documentation showing the patient declined, could not tolerate, or failed a pessary trial. Bivariate analyses were used to compare demographics, medical history, surgical route, concomitant procedures (colpopexy or colporrhaphy), and intra- and postoperative complications between women with and without pessary offer. Hierarchical logistic regression was used to determine factors independently associated with pessary offer. Risk-adjusted pessary offer rates by hospital were calculated.

RESULTS

The adjusted rate of pessary offer was 25.2%, ranging from 3 to 76% per hospital. Bivariate comparisons showed differences between women with and without pessary offer in age, tobacco use, prior pelvic surgery, insurance status, surgical approach, secondary indication for surgery, concomitant prolapse procedure, teaching hospital status and hospital bed size. In logistic regression, odds of pessary offer increased with age > 55 years (OR 1.45, 95% CI 1.12-1.88, p = 0.006), Medicare insurance (OR 1.65, 95% CI 1.30-2.10, p < 0.0001), and a concomitant procedure (OR 1.5, 95% CI 1.16-1.93, p = 0.002). Postoperative urinary tract infections were more common in patients offered a pessary (6.4% vs. 2.5%, p < 0.0001), but other complications were similar.

CONCLUSIONS

Overall, only one-quarter of hysterectomies for prolapse in MSQC hospitals had documentation of pessary counseling-suggesting an opportunity to improve documentation, counseling regarding pessary use, or both.

Interactions among pelvic organ protrusion, levator ani descent, and hiatal enlargement in women with and without prolapse

BACKGROUND

Pelvic organ prolapse has 2 components: (1) protrusion of the pelvic organs beyond the hymen; and (2) descent of the levator ani. The Pelvic Organ Prolapse Quantification system measures the first component, however, there remains no standard measurement protocol for the second mechanism.

OBJECTIVE

We sought to test the hypotheses that: (1) difference in the protrusion area is greater than the area created by levator descent in prolapse patients compared with controls; and (2) prolapse is more strongly associated with levator hiatus compared to urogenital hiatus.

STUDY DESIGN

Midsagittal magnetic resonance imaging scans from 30 controls, 30 anterior predominant, and 30 posterior predominant prolapse patients were assessed. Levator area was defined as the area above the levator ani and below the sacrococcygeal inferior pubic point line. Protrusion area was defined as the protruding vaginal walls below the levator area. The levator hiatus and urogenital hiatus were measured. Bivariate analysis and multiple comparisons were performed. Bivariate logistic regression was performed to assess prolapse as a function of levator hiatus, urogenital hiatus, levator area, and protrusion. Pearson correlation coefficients were calculated.

RESULTS

The levator area for the anterior (34.0 ± 6.5 cm²) and posterior (35.7 ± 8.0 cm²) prolapse groups were larger during Valsalva compared to controls (20.9 ± 7.8 cm², P < .0001 for both); similarly, protrusion areas for the anterior (14.3 ± 6.2 cm²) and posterior (14.4 ± 5.7 cm²) prolapse groups were both larger compared to controls (5.0 ± 1.8 cm², P < .0001 for both). The levator hiatus length for the anterior (7.2 ± 1 cm) and posterior (6.9 ± 1 cm) prolapse groups were longer during Valsalva compared to controls (5.2 ± 1.5 cm, P < .0001 for both); similarly, urogenital hiatus lengths for the anterior (5.7 ± 1 cm) and posterior (6.3 ± 1.1 cm) prolapse groups were both longer than controls (3.8 ± 0.8 cm, P < .0001 for both). The difference in levator area in prolapse patients compared with controls was greater than the difference in protrusion area (14.0 ± 7.2 cm² vs 9.4 ± 5.9 cm², P < .0002). The urogenital hiatus was more strongly associated with prolapse than the levator hiatus (odds ratio, 12.9; 95% confidence interval, 4.1-39.2, and odds ratio, 4.3; 95% confidence interval, 2.3-7.5). Levator hiatus and urogenital hiatus are both correlated with levator and protrusion areas, and all were associated with maximum prolapse size (P ≤ .001, for all comparisons).

CONCLUSION

In prolapse, the levator area increases more than the protrusion area and both the urogenital hiatus and levator hiatus are larger. The odds of prolapse for an increase in the urogenital hiatus are 3 times larger than for the levator hiatus, which leads us to reject both the original hypotheses.

Are perioperative bundles associated with reduced postoperative morbidity in women undergoing benign hysterectomy? Retrospective cohort analysis of 16,286 cases in Michigan

BACKGROUND

Healthcare teams that frequently follow a bundle of evidence-based processes provide care with lower rates of morbidity. Few process bundles to improve surgical outcomes in hysterectomy have been identified.

OBJECTIVE

The purpose of this study was to investigate whether a bundle of 4 perioperative care processes is associated with fewer postoperative complications and readmissions for hysterectomies in the Michigan Surgical Quality Collaborative.

STUDY DESIGN

A bundle of perioperative care process goals was developed retrospectively with 30-day peri- and postoperative outcome data from the Hysterectomy Initiative in Michigan Surgical Quality Collaborative. All benign hysterectomies that had been performed between January 2013 and January 2015 were included. Based on evidence of lower complication rates after benign hysterectomy, the following processes were considered to be the "bundle": use of guideline-appropriate preoperative antibiotics, a minimally invasive surgical approach, operative duration <120 minutes, and avoidance of intraoperative hemostatic agent use. Each process was considered present or absent, and the number of processes was summed for a bundle score that ranged from 0-4. Cases with a score of zero were excluded. Outcomes measured were rates of complications (any and major) and hospital readmissions, all within 30 days of surgery. Postoperative events that were considered a "major complication" included acute renal failure, cardiac arrest that required cardiopulmonary resuscitation, central line infection, cerebral vascular accident, death, deep vein thrombosis, intestinal obstruction, myocardial infarction, pelvic abscess, pulmonary embolism, rectovaginal fistula, sepsis, surgical site infection (deep and organ-space), unplanned intubation, ureteral obstruction, and ureterovaginal and vesicovaginal fistula. The outcome "any complication" included all those events already described in addition to blood transfusion within 72 hours of surgery, urinary tract infection, and superficial surgical site infection. Outcomes were adjusted for patient demographics, surgical factors, and hospital-level clustering effects.

RESULTS

There were 16,286 benign hysterectomies available for analysis. Among all hysterectomies that were reviewed, 33.6% met criteria for all bundle processes; however, there was wide variation in the rate among the 56 hospitals in the study sample with 9.1% of cases at the lowest quartile and 60.4% at the highest quartile of hospitals that met criteria for all bundle processes. Overall, the rate of any complication was 6.8% and of any major complication was 2.3%. The rate of hospital readmissions was 3.6%. After adjustment for confounders, in cases in which all bundle criterion were met compared with cases in which all bundle criterion were not met, the rate of any complications increased from 4.3-7.8% (P<.001); major complications increased from 1.7-2.6% (P<.001), and readmissions increased from 2.6-4.1% (P<.001). After adjustment for confounders, hospitals with greater rates of meeting all 4 criteria were associated significantly with lower hospital-level rates of postoperative complications (P<.001) and readmissions (P<.001).

CONCLUSIONS

This multiinstitutional evaluation reveals that reduced morbidity and readmission are associated with rates of bundle compliance. The proposed bundle is a surgical goal, which is not possible in every case, and there is significant variation in the proportion of cases meeting all 4 bundle processes in Michigan hospitals. Implementation of evidence-based process bundles at a healthcare system level are worthy of prospective study to determine whether improvements in patient outcomes are possible.

Plexiform schwannoma: an unusual clitoral mass

Acquired clitoral enlargement is a rare condition resulting from a variety of etiologies, including tumors and excess androgens. Few cases of nonmalignant schwannoma, a benign tumor of the peripheral nerve sheath, have been reported in the literature as causes of clitoral enlargement in patients without known neurofibromatosis. These painless, slow-growing tumors rarely recur once excised. We present the initial investigation of a patient with a large clitoral schwannoma and subsequent treatment with partial vulvectomy. The workup, including advanced pelvic imaging for diagnosis and surgical planning, as well as removal of the clitoral tumor with preservation of functional tissue and restoration of normal vulvar anatomy despite a large excision, is demonstrated.

Tobacco use as a risk factor for reoperation in patients with stress urinary incontinence: a multi-institutional electronic medical record database analysis

INTRODUCTION AND HYPOTHESIS

Recurrence rates of stress urinary incontinence after surgery are reported to be between 8 to 15%. Both surgical technique and non-surgical risk factors have been shown to affect post-operative outcomes. Tobacco use is a possible risk factor that may increase the surgical failure rate, however, there are currently conflicting reports in the literature regarding the affect of tobacco use on surgical outcomes. Our objective is to evaluate the effect of tobacco use on the risk of repeat surgery for stress urinary incontinence (SUI).

METHODS

We performed a retrospective cohort analysis using a de-identified clinical database from a large multi-institution electronic health records data web application EPM:ExploreTM (Explorys Inc, Cleveland, Ohio) to identify women with and without a history of tobacco use who underwent reoperation for stress urinary incontinence within 2 years of the first surgery. We then evaluated previously described risk factors for reoperation: diabetes mellitus (DM), pelvic organ prolapse (POP), anti-muscarinic (AM) use at initial surgery, obesity, and advanced age on rate of reoperation and the impact of tobacco use on these risk factors.

RESULTS

Tobacco use was associated with an increased rate of a second surgery for SUI (OR=1.43, p <0.001), as was anti-muscarinic use (OR = 1.68, p<0.001), DM (OR = 1.21, p = 0.005), age >50 years (OR= 1.16, p = 0.040), and BMI > 30 kg/m2 (OR = 2.97 p<0.001). The odds of a second surgery for SUI in patients who used tobacco and anti-muscarinic medications or had pelvic organ prolapse were lower when compared to non-users. The odds of a second surgery for SUI were higher in patients who used tobacco and had asthma when compared to non-users who had asthma.

CONCLUSIONS

Tobacco increases the overall risk of second surgery for SUI, however, in patients with specific risk factors, tobacco use is associated with a decrease risk of reoperation.