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Original Study

Translabial ultrasound indices of failed pessary fittings in women with symptomatic pelvic organ prolapse

Xu, Hainan MD1; Wu, Wenjing BS2; Wang, Xinlu PhD3; Xia, Zhijun PhD1

Author Information
doi: 10.1097/GME.0000000000001939

Abstract

Pelvic organ prolapse (POP) is a common female pelvic floor dysfunction (PFD) that adversely impacts quality of life. Affected women may be surgically treated or managed conservatively, primarily via vaginal pessaries. The latter has been used to treat symptomatic POP for thousands of years.1 Not only is there immediate relief of symptoms, but some data suggest that long-term use of a pessary may prevent the progression of prolapse.2 Given their efficacy and safety, vaginal pessaries are considered first-line treatment for symptomatic POP.3 Furthermore, in nearly two-thirds of women with symptomatic POP, a pessary is preferred as initial treatment.4

Despite the widespread global acceptance of vaginal pessaries, the recently reported lifetime risk of surgical intervention for symptomatic POP within the US is estimated at 20%.5 Thus, not all attempted pessary fittings are successful; and because the rate of successful fittings varies considerably (41%-86%),6-8 factors associated with failed fittings should be explored. The most common predictors of failure cited in the literature are shorter vaginal length, wider vaginal introitus,6,9,10 posterior compartment prolapse,9 urinary incontinence (UI),6,11 prior prolapse surgery or hysterectomy, increased parity,7,9,12 advanced prolapse,13,14 and age<65 years.15 However, there is little clinical research on objective anatomic measures that may predict fitting failures.

The most important organ-supportive muscle of the pelvic floor is the levator ani muscle (LAM). The growing use of three- or four-dimensional translabial ultrasound (TLUS) in assessments of pelvic floor structure and function has increasingly shed light on relations between TLUS measures of LAM and POP. Both LAM avulsion and hiatal area (HA) upon Valsalva (included in TLUS evaluations) have shown associations with POP and POP recurrence in a select population of women with pelvic floor dysfunction.16 Moreover, LAM avulsion and sizeable hiatal dimensions (hiatal circumference [HC] and HA) have been linked to 1-year pessary retention failures.17 Still, in this particular setting, the predictive natures of such parameters have not been adequately investigated to date. The present study was undertaken to assess TLUS-determined LAM avulsion and excess hiatal expanse as indices of failed pessary fittings in women with symptomatic POP.

METHODS

Participant selection

In retrospect and with approval of our Institutional Review Board (ID: 2021PS170K), we studied women presenting between May 2018 and December 2020 to the Pelvic Floor Disease Diagnosis and Treatment Center (Liaoning Province, China), each seeking treatment for symptomatic POP. Inclusion criteria were vaginal pessary as the first choice of treatment and TLUS before pessary placement. Failure to complete the fitting process was grounds for exclusion. All participants were examined and staged by one urogynecologist with experience (≥10 y) conducting International Continence Society Pelvic Organ Prolapse Quantification (POP-Q) examinations.18 One experienced sonographer, blinded to outcomes of pessary fittings, performed all TLUS assessments. Data on participant age, gravidity, parity, menopausal status, body mass index (BMI), history of hysterectomy or prior POP surgery, UI symptoms, fitting result (yes/no), POP-Q stage, and TLUS parameters, were extracted from medical records.

Translabial ultrasound imaging

TLUS was undertaken with participants in dorsal lithotomy positions (after bladder emptying and defecation), using either a Voluson E8 (GE Healthcare, Chicago, IL) or a Resona 8 (Mindray Medical, Shenzhen, China) ultrasound system equipped with a curved-array transducer (4-8 MHz, 85° acquisition angle).19 Volume acquisitions were obtained at rest, upon maximal Valsalva maneuver, and upon maximal pelvic-floor muscle contraction, as described by Dietz et al.20 For optimal analyses, at least three volumes were obtained per patient during Valsalva maneuvers, each at least 6-seconds long and in the absence of levator coactivation. LAMs were assessed by tomographic ultrasound imaging at 2.5-mm slice intervals, using volumes acquired at maximum pelvic-floor muscle contraction and from 5 mm below to 12.5 mm above planes of minimal hiatal dimensions. Levator-urethra gap, also described by Dietz et al,21 was measured as well. We defined LAM avulsion as complete avulsion in at least the three central slices, with a levator-urethra gap cutpoint of 23.6 mm.22 HC and HA were assessed in the plane of least hiatal dimensions upon maximal Valsalva maneuver. In the mid-sagittal plane, the inferior margin of the symphysis pubis (SP) was set as a reference to assess prolapse of anterior, apical, and posterior compartments, recording inferiormost aspects of bladder, cervix, and rectal ampulla, respectively (relative to SP) on maximal Valsalva. After hysterectomy, apical compartment prolapse assessments referenced the position of the vaginal vault (rather than the cervix). Downward displacement of abdominal contents (mostly small bowel) into the vagina, dorsal to an anechoic bladder and ventral to rectal ampulla and anal canal, constituted evidence of enterocele.23

Pessary fittings

At our treatment center, we typically offer expectant management, vaginal pessary, or surgical intervention during the first patient visit for symptomatic POP. One experienced and trained nurse conducted all the fittings for participants who opted for pessaries as first-line treatments. Two types of medical-grade silicone pessaries were available, either a ring with support (51, 58, 64, 70, or 76 mm in diameter) or a Gellhorn design (51, 57, 64, 70, or 76 mm in diameter). Women were initially fitted with either pessary during the first visit. If a participant experienced discomfort or pain, insertion of a smaller size pessary was attempted, and a larger size was inserted if the pessary could not be retained. If the participant failed to retain any size, another type was immediately placed after the same procedure. Once comfortably fitted, the participant was asked to ambulate and void during the office visit. If the pessary was comfortably retained, the initial fitting was considered successful, and the participant or her caregiver was instructed on how to manage the pessary, including its regular removal, cleaning, and replacement. Generally, we recommend that at least once a week participants remove and clean their pessaries before going to bed and reinsert it the next morning. The removal of the pessary was also recommended before sexual activity regardless of the pessary type. Participants were scheduled to return to the center 2 weeks after the first visit to assess the fitting or sooner if they encountered a problem. Women who reported discomfort or expulsion were offered another size or type of pessary for refitting. They returned again after 2 weeks for a third visit. Follow-up visits were also scheduled as needed, until participants had tried both types and all sizes of pessaries available in our treatment center. Moreover, a pessary fitting was considered successful if a participant who was fitted with a pessary either in the initial fitting or in the refitting trials continued to use it for 2 weeks, regardless of the number of refittings.

Calculation of sample size

The primary objective of the study was to assess TLUSdetermined excess hiatal expanses as indices of failed pessary fittings in women with symptomatic POP. Referring to previous reports, the proportion of successful fittings of ring pessaries was about 63%6-8 and the means of HA in the successful and failed group were 29.0 and 33.0 cm2, respectively, with a standard deviation (SD) of 8.0.17,24 After calculating the sample size, 115 and 68 participants in the successful and failed groups were needed to achieve 90% power to reject the null hypothesis of equal means when the population mean difference was μ1-μ2 = 29.0-33.0=-4.0, with an SD for both groups of 8.0 and a significance level (alpha) of 0.050 using a two-sided twosample equal-variance t test.

Statistical analysis

Quantitative data were expressed as mean ± SD or median (range) values. Independent-sample t test or Mann-Whitney U test (for continuous data that do not fit normal distributions) served for group-wise comparisons, the relations between categorical variables determined by the Chi-square test. The relations between a categorical variable and one continuous variable were determined by Spearman rank correlation. We used uni- and multi-variate logistic regression models to ascertain factors predicting failed pessary fittings. Variables of significance by univariate analysis were input into a multiple backward step-wise logistic regression model. The calculation of sample size was done using PASS 15 Power Analysis and Sample Size Software (NCSS, LLC. Kaysville, UT). Other computations were driven by standard software (SPSS Statistics v22.0; IBM Corp, Armonk, NY), setting significance at P < 0.05.

RESULTS

Between May 2018 and December 2020, a total of 394 women with symptomatic POP submitted to pessary fittings in our clinic. Each had undergone TLUS in advance, although some (n = 21) did not complete their fittings and were subsequently excluded. Among the remaining 373 women, 255 (68.4%) achieved successful fittings of either ring pessaries with support (n = 90) or Gellhorn pessaries (n = 165).

Population characteristics

Demographic and clinical characteristics (including POP-Q stage and TLUS parameters) of the participant population are shown in Table 1. Most women (341/373, 91.4%) were postmenopausal, but none had received hormonal therapy. There were 182 (49.9%) reporting symptoms of UI. In terms of POP-Q staging, 121 participants (32.4%) were stage II, 219 (58.7%) were stage III, and 33 (8.8%) were stage IV. Rates of pessary fitting success were distributed as follows: stage II, 63.6% (77/121); stage III, 71.2% (156/219); and stage IV, 66.7% (22/33). Twenty-two women had undergone previous hysterectomies for either prolapse or for gynecologic diseases, only five participants had past prolapse surgeries other than hysterectomy. Overall, LAM avulsion was identified by TLUS in 37 (9.9%) women, including 12 (32.4%) with leftsided, 11 (29.7%) with right-sided, and 14 (37.8%) with bilateral avulsion. Manifestations of enterocele were evident in 25 participants.

TABLE 1. - Participant characteristics and univariate analysis of indices for failed pessary fittings

Characteristic

Successfula (N = 255)

Faileda (N = 118)

Pb

Age, y

64.72 ± 10.30

61.54 ± 10.25

0.006

Gravidityc

3 (1, 8)

3 (2, 6)

1.0

Parityc

2 (1, 8)

2 (1, 6)

0.07

BMI, kg/m2 c

24.34 ± 2.77

24.14 ± 2.96

0.5

Postmenopausal

0.006

Yes

240 (94.1)

101 (85.6)

No

15 (5.9)

17 (14.4)

Previous hysterectomy

1.0

Yes

15 (5.9)

7 (5.9)

No

240 (94.1)

111 (94.1)

History of urinary incontinencec

0.9

Yes

124 (49.6)

58 (50.4)

No

126 (50.4)

57 (49.6)

POP-Q stage

0.3

II

77 (30.2)

44 (37.3)

III

156 (61.2)

63 (53.4)

IV

22 (8.6)

11 (9.3)

LAM avulsion

0.001

Yes

16 (6.3)

21 (17.8)

No

239 (93.7)

97 (82.2)

Enterocele

0.02

Yes

12 (4.7)

13 (11.0)

No

243 (95.3)

105 (89.0)

Inferiormost aspect of bladder on Valsalva

0.9

At/above SP

34 (13.3)

15 (12.7)

Below SP

221 (86.7)

103 (87.3)

Inferiormost aspect of cervix on Valsalvad

0.03

At/above SP

59 (23.1)

16 (13.6)

Below SP

196 (76.9)

102 (86.4)

Inferiormost aspect of rectal ampulla on Valsalva

0.2

At/above SP

71 (27.8)

26 (22.0)

Below SP

184 (72.2)

92 (78.0)

HC on Valsalva, cm

19.70 ± 2.50

20.36 ± 2.33

0.02

HA on Valsalva, cm2

27.27 ± 6.99

29.67 ± 7.14

0.003

BMI, body mass index; HA, hiatal area; HC, hiatal circumference; LAM, levator ani muscle; POP-Q, pelvic organ prolapse quantification; SD, standard deviation; SP, symphysis pubis.
aData expressed as mean ± SD, median (range), or n (%).
bAssessed via t test, Mann-Whitney U test, or Chi-square test.
cVariables with missing data (the number of participants with missing data in the successful/failed group was 28/15 for Gravidity, 25/15 for Parity, 27/14 for BMI, and 5/3 for History of urinary incontinence, respectively).
dPosition of the vaginal vault (rather than the cervix) recorded after hysterectomy to assess apical compartment prolapse.

Uni- and multi-variate analyses

In comparing failed versus successful group demographics (Table 1, Fig. 1), younger age (61.54 ± 10.25 y vs 64.72 ± 10.30 years; P = 0.006) and premenopausal status (14.4% vs 5.9%; P = 0.006) correlated significantly with failed pessary fittings by univariate analysis. However, there were no significant differences in other demographic variables, including gravidity, parity, BMI, symptoms of UI, prior hysterectomy, or POP-Q stage.

F1
FIG. 1.:
Univariate analysis of factors distinguishing successful and failed pessary fitting groups: (A) age; (B) hiatal circumference (HC) on Valsalva; (C) hiatal area (HA) on Valsalva; (D) menopausal status; (E) levator ani muscle (LAM) avulsion; (F) enterocele; and (G) inferiormost aspect of cervix on Valsalva.

Univariate analyses of TLUS parameters in women with failed versus successful pessary fittings (Table 1, Fig. 1) revealed significant differences in HC (20.36 ± 2.33 cm vs 19.70 ± 2.50 cm; P = 0.02) and HA (29.67 ± 7.14 cm2 vs 27.27 ± 6.99 cm2; P = 0.003), more sizeable values associated with fitting failures. Failed fittings were also significantly more likely in women with (vs without) LAM avulsions (odds ratio [OR] = 3.23, 95% confidence interval [CI] = 1.62-6.46; P = 0.001) and with (vs without) enteroceles (OR = 2.51, 95% CI = 1.11-5.68; P = 0.03). With respect to degrees of prolapse, we similarly found a significant difference in fitting success for women with cervical positioning at or above (vs below) SP (OR = 0.52, 95% CI = 0.29-0.95; P = 0.03) (Table 2). Apical compartment prolapse beyond SP showed a significant association with fitting failure, whereas anterior or posterior compartment prolapse did not.

TABLE 2. - Uni- and multi-variate analyses (logistic regression) of indices for failed pessary fittings

Univariate analysis

Multivariate analysisa

Characteristic

OR

95% CI

P

OR

95% CI

P

Age (continuous)

0.97

0.95-0.99

0.006

0.98

0.95-1.00

0.04

Post- vs pre-menopausal

0.37

0.18-0.77

0.008

-

-

-

LAM avulsion (yes/no)

3.23

1.62-6.46

0.001

2.87

1.32-6.25

0.008

Enterocele (yes/no)

2.51

1.11-5.68

0.03

2.70

1.12-6.50

0.03

Inferiormost aspect of cervix on Valsalva (at/above vs below SP)b

0.52

0.29-0.95

0.03

-

-

-

HC on Valsalva (continuous)

1.12

1.01-1.23

0.03

-

-

-

HA on Valsalva (continuous)

1.05

1.02-1.08

0.003

1.04

1.01-1.08

0.02

CI, confidence interval; HA, hiatal area; HC, hiatal circumference; LAM, levator ani muscle; OR, odds ratio; SP, symphysis pubis.
aBackward step-wise logistic regression.
bPosition of the vaginal vault (rather than the cervix) recorded after hysterectomy to assess apical compartment prolapse.

All significant predictors of failed pessary fittings (P < 0.05) determined by univariate analysis served as input for a multivariate logistic regression model (Table 2). Ultimately, younger age (OR = 0.98, 95% CI = 0.95-1.00; P = 0.04), sizeable HA on Valsalva (OR = 1.04, 95% CI = 1.01-1.08; P = 0.02), LAM avulsion (OR = 2.87, 95% CI = 1.32-6.25; P = 0.008), and enterocele (OR = 2.70, 95% CI = 1.12-6.50; P = 0.03) emerged as independent predictors of failed pessary fittings.

Correlation between ultrasound parameters and POP-Q stage

When correlating translabial ultrasound parameters with the POP-Q stage, we found that the inferiormost aspect of the cervix beyond SP, HC, and HA on Valsalva were significantly associated with the POP-Q stage. The larger the HA and HC detected, the more severe the POP (Table 3).

TABLE 3. - Ultrasound parameters correlation with POP-Q stage

POP-Q stagea

Characteristic

II

III

IV

Pb

LAM avulsion

0.2

Yes

17 (14%)

18 (8.2%)

2 (6.1%)

No

104 (86%)

201 (91.8%)

31 (93.9%)

Enterocele

0.2

Yes

5 (4.1%)

16 (7.3%)

4 (12.1%)

No

116 (95.9%)

203 (92.7%)

29 (87.9%)

Inferiormost aspect of bladder on Valsalva

0.1

At/above SP

20 (16.5%)

28 (12.8%)

1 (3%)

Below SP

101 (83.5%)

191 (87.2%)

32 (97%)

Inferiormost aspect of cervix on Valsalvac

0.008

At/above SP

34 (28.1%)

39 (17.8%)

2 (6.1%)

Below SP

87 (71.9%)

180 (82.2%)

31 (93.9%)

Inferiormost aspect of rectal ampulla on Valsalva

0.4

At/above SP

35 (28.9%)

56 (25.6%)

6 (18.2%)

Below SP

86 (71.1%)

163 (74.4%)

27 (81.8%)

HC on Valsalva, cm

19.69 ± 2.51

19.84 ± 2.36

21.35 ± 2.73

0.05

HA on Valsalva, cm2

27.32 ± 7.09

27.36 ± 6.27

32.65 ± 8.72

0.03

HA, hiatal area; HC, hiatal circumference; LAM, levator ani muscle; POP-Q, pelvic organ prolapse quantification; SD, standard deviation; SP, symphysis pubis.
aData expressed as N (%) or mean ± SD.
bAssessed via Chi-square test or Spearman rank correlation.
cPosition of the vaginal vault (rather than the cervix) recorded after hysterectomy to assess apical compartment prolapse.

DISCUSSION

The aim of this study was to investigate TLUS parameters as indices of failed pessary fittings in women with symptomatic POP. Our findings indicate that a number of such parameters, namely, LAM avulsion, enterocele, and sizeable HA upon Valsalva, are indeed independent predictors of ineffectual pessary fittings.

Vaginal pessaries commonly used to treat POP, and are offered as first-line treatment by 75% of specialty clinicians in the US.25 However, they are not fitted successfully in all women. The fitting process is also time consuming and may become tedious if multiple attempts are required. It is thus beneficial to identify women for whom pessary fittings will likely fail, alerting them to this likelihood and allowing doctors to reconsider this approach.

Most studies conducted to date have focused on successful fitting rates or continued use rates and related clinical factors.7,8,26,27 Unfortunately, clinical assessment alone is a rather inadequate means of assessing pelvic floor function and anatomy. TLUS, on the other hand, is safe, simple, and easily replicated28-31 and provides real-time organ assessment. Not only is it useful for quantifying prolapse of pelvic organs23,32,33 but needed insight into underlying organs and functional anatomy is also conveyed.23 Because TLU S fills in the blanks, its use for investigating POP is increasing. There is limited data as yet on predicting failed pessary fittings through objective anatomic measures, but the present findings confirm this relation, allowing patients and doctors to better decide treatment choice.

As the most important muscle of the pelvic floor, the LAM is critical for pelvic organ support, leading to POP when defective. Previous studies have found that LAM avulsion bears an association with symptoms of POP and severe prolapse34,35 and impacts outcomes after prolapse surgery.36 At 6 weeks after primary prolapse surgery, participants with avulsed (vs intact) LAMs demonstrated worse anterior vaginal support.37 It also appears that mesh repair significantly reduces subjective and objective recurrences in women with LAM avulsions, perhaps benefitting those with advanced POP as a consequence.38 Although DeLancey et al39 have previously documented LAM avulsion in > 50% of women with POP, it was detectable by TLUS in just 37 (9.9%) of our participants. However, LAM avulsion has been linked to vaginal delivery,40 national proclivities, delivery rates (vaginal and cesarean), forceps use during delivery, racial status, and more, so inconsistencies may be expected. A recent report has indicated that LAM avulsion does not predict successful 3-month pessary use,24 although Cheung et al17 observed a threefold increase in 1-year risk of vaginal pessary expulsion in the presence of LAM avulsion. Our participants with TLUS-detected LAM avulsion likewise showed a 2.87-fold increase in the risk of failed pessary fitting.

Hiatal ballooning is known to be an independent risk factor for POP,41 and our study also demonstrated that hiatal ballooning correlated with the POP-Q stage (Table 3). HA on maximal Valsalva effort has been shown predictive of prolapse recurrence after surgery.36,42 A past study has also disclosed that sizeable HA on Valsalva is predictive of pessary failure,17,24 each 1-cm increment in HA beyond 25 cm2 increasing the likelihood of failure by 5%.24 In our study population, both HC and HA on Valsalva differed significantly in failed and successful pessary fitting groups. LAM avulsion and excessive hiatal distension are actually manifestations of pelvic-floor muscle defects, making it difficult to retain pessaries above the levator plate and leading to fitting failures. Our data further indicate a nearly threefold greater risk of failed pessary fittings in conjunction with enteroceles. This may be explained by the fact that enteroceles are indirect reflections of support defects in the apical pelvic fascia, signaling a lack of structure needed for pessary retention.

A number of earlier investigations have shared our study goals, most of them focused on clinical characteristics rather than anatomic features and ultrasound parameters. To our knowledge, this is the first study to address TLUS parameters in this regard, identifying LAM avulsion, enterocele, and sizeable HA on Valsalva as independent predictors of fitting failures. This approach may aid in the screening, counseling, and expeditious treatment of women who are ill-suited for pessary management of symptomatic POP. The strengths of this study include its large population sampling and the fact that sonographic assessments were fully blinded events, devoid of any clinical data (especially pessary fitting results). Another asset was that all women with prolapse were evaluated, not just poor surgical candidates or those who declined surgery. This helped minimize selection bias. The retrospective design is an acknowledged limitation, albeit tempered by ample patient numbers. Due to the retrospective nature of our study, data regarding gravidity, parity, and BMI were incomplete. Important data that influence levator avulsion, such as the use of forceps and infant birth weight, were not collected. Additionally, there were only two available pessary types with limited sizes (51-76 mm in diameter). Therefore, our results may merely apply to similar circumstances. Further prospective trials with a larger sample size and different ethnicities are needed for validation.

CONCLUSIONS

In conclusion, we have identified younger age, LAM avulsion, enterocele, and sizeable HA on Valsalva as independent predictors of likely pessary failures in women with symptomatic pelvic organ prolapse. Translabial ultrasound appears to be essential in advancing prolapse treatment, enabling the conveyance of more reasonable therapeutic expectations during patient counseling.

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Keywords:

Hiatal area; Hiatal circumference; Levator ani muscle avulsion; Pelvic organ prolapse; Ultrasound.

© 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The North American Menopause Society.