Reliability and validity of pelvic floor muscle displacement measurements during voluntary contractions

Most of the pelvic floor muscle functions in women differ in different body positions, yet others remain similar: systematic review with meta-analysis

Objectives

This systematic literature review and meta-analysis aimed to determine the effect of body position on the measurement of pelvic floor muscle (PFM) contractility and to analyze the influential factors.

Data sources

Five databases (PubMed, Web of Science, EMBASE, Cochrane Library and Scopus) were searched for relevant studies published up to 12nd October 2023.

Study selection or eligibility criteria

Included cross-sectional studies had to involve the assessment of pelvic floor muscle function in at least two positions.

Study appraisal and synthesis methods

We calculated standardized mean difference (SMD) with 95% confidence intervals (CI) to ascertain the potential effect of body position on outcomes.

Results

In total, we included 11 cross-sectional studies to ascertain the potential effect of body position on outcomes. There was no statistical difference in the results of maximum voluntary contraction (MVC) of the pelvic floor muscles when assessed in between supine and standing positions (SMD -0.22; 95% CI -0.72 to 0.28; p = 0.38). The results of the meta-analysis showed significantly larger values of resting voluntary contractions (RVC) measured in the standing position compared to the supine position (SMD -1.76; 95% CI -2.55 to -0.97; p < 0.001). Moreover, pelvic floor muscle movement during pelvic floor muscle contraction in the standing position was significantly better than that measured in the supine position (SMD -0.47; 95% CI -0.73 to 0.20; P < 0.001).

Conclusion

The results of this study showed that the RVC and PFM movement varied with the position of the assessment. In contrast, MVC values are independent of the assessment position and can be selected according to clinical needs.

Systematic review registration

PROSPERO, identifier CRD42022363734, https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022363734.

Effects of Pelvic-Floor Muscle Training in Patients with Pelvic Organ Prolapse Approached with Surgery vs. Conservative Treatment: A Systematic Review

The aim of this systematic review was to explore the effectiveness of pelvic-floor muscle training (PFMT) in the treatment of women with pelvic organ prolapse (POP) who had undergone either surgery or only conservative treatment, based on a selection of randomized clinical trials (RCT). The search was carried out in PubMed, Cochrane, Scopus, CINAHL, and PEDro databases between April 2021 and October 2021 using the following MeSH terms or keywords: “pelvic organ prolapse”, “POP”, “pelvic floor muscle training”, “pelvic floor muscle exercise”, “kegel exercise”, and “surgery”. The methodological quality of the studies was assessed using the PEDro scale. Eighteen RCTs were included in this review. The findings showed improvements in symptoms associated with POP, in pelvic-floor function, and in quality of life in women who performed a PFMT protocol. However, PFMT did not produce significant changes in sexual function, and the results of the change in POP stage were inconclusive. When viewing PFMT as a complementary treatment to surgery, no significant improvements were observed in any of the analyzed variables. In conclusion, a PFMT program is an effective way to improve the pelvic, urinary, and intestinal symptoms associated with POP; function of the pelvic floor; and quality of life. PFMT as an adjunct to surgery does not seem to provide a greater benefit than surgical treatment alone. RCTs of higher methodological quality, with a larger sample size and a longer follow-up, are needed to confirm the results.

Effect of hip external rotator muscle contraction on pelvic floor muscle function and the piriformis

INTRODUCTION AND HYPOTHESIS

There is a lack of in-depth understanding of the muscles surrounding the pelvic floor muscle (PFM). The study aimed to investigate the functional relationship between PFM and hip external rotator muscles by observing the piriformis muscle thickness and displacement of the bladder base under different contraction conditions of the hip external rotator and/or PFM. We hypothesized that PFM function would be the strongest when the hip external rotator and PFM contracted simultaneously and that during PFM contraction, the piriformis muscle would act as an auxiliary muscle and show coactivation.

METHODS

The participants included 13 healthy adult women (mean age 23.8 ± 2.8 years). The three contraction conditions were PFM contraction, hip external rotator contraction, and simultaneous contraction of the hip external rotator and PFM. During the tasks, the piriformis muscle thickness and bladder base displacement were measured using ultrasonography and compared among the contraction conditions using one-way analysis of variance.

RESULTS

Significant differences were noted in bladder base displacement among the three contraction conditions (P < 0.01), with PFM contraction having the highest value. The piriformis muscle thickness showed the greatest increase in simultaneous contraction.

CONCLUSIONS

In our study, we showed PFM contraction positively influences piriformis contraction, while PFM function operationalized by bladder base displacement was highest during PFM contraction alone.

Pelvic floor muscle function in the standing position in women with pelvic floor dysfunction

INTRODUCTION AND HYPOTHESIS

Clinical assessment of the pelvic floor muscles (PFMs) in a standing position may provide a more valid representation of PFM function experienced by patients in daily life than assessment in the lying position. The primary aim of this study was to examine PFM function in a standing versus a lying position in parous women with any type of urinary incontinence and/or pelvic organ prolapse.

METHODS

In this exploratory cross-sectional study, participant symptom status was determined using the Australian Pelvic Floor Questionnaire. Pelvic floor muscle function was assessed in standing and lying positions with a randomised order of testing. The primary outcome measure was vaginal squeeze pressure (VSP) using intra-vaginal manometry. Secondary outcomes included vaginal resting pressure, total PFM work and digital muscle testing. The difference between PFM function in a standing position compared with a lying position was analysed using paired t test or Wilcoxon's signed rank test.

RESULTS

Vaginal squeeze pressure assessed with manometry was higher in a standing than in a lying position (p = 0.001): standing (mean [SD]) 24.90 [12.67], lying 21.15 [14.65]. In contrast, PFM strength on digital muscle testing was lower in a standing position than in a lying position.

CONCLUSIONS

This study has demonstrated that PFM function in a standing position is different from that in a lying position in women with pelvic floor dysfunction. Whether the higher VSP observed in a standing position reflects a true difference in strength between positions, or a higher pressure reading due to incorrect PFM contraction technique in a standing position is uncertain. Further research with larger cohorts and a measurement tool that can accurately distinguish a rise in intra-vaginal pressure from PFM contraction rather than increasing intra-abdominal pressure is required to confirm this difference, and the clinical significance of any difference.

Reliability of Pelvic Floor Muscle Assessment with Transabdominal Ultrasound in Young Nulliparous Women

The aim of this study was to assess the reliability of pelvic floor muscles evaluation via transabdominal ultrasonography in young nulliparous women and to present the methodology for quantitative assessment of the ultrasound image of the pelvic floor muscles visible as displacement of the posterior wall of the bladder, caused by action of the pelvic floor muscles. The study comprised 30 young, Caucasian, nulliparous women (age 22-27; 168.6 ± 5.1 cm; 57.1 ± 11.8 kg) without pelvic floor muscle dysfunctions. The intra-rater, test-retest and inter-rater reliability of pelvic floor muscles evaluation was performed using transabdominal ultrasound at rest and during voluntary contraction. The reliability was assessed at three points of the image (at the middle, on the right and left side). The reliability of the three-point measurement of the pelvic floor muscles transabdominal ultrasound is excellent in the case of intra-rater assessments, both at rest (ICC = 0.98-0.99) and during contraction (ICC = 0.97-0.98); moderate at rest (ICC = 0.54-0.62) and poor during contraction (ICC = 0.22-0.50) in the case of test-retest assessment; excellent at rest (ICC = 0.95-0.96), and good during contraction (ICC = 0.81-0.87) in the case of inter-rater assessment. Transabdominal ultrasound is a reliable method of pelvic floor muscle evaluation. The three-points of assessment used in our study allowed for broader and more comprehensive imaging of the pelvic floor muscle, e.g., for quantitative detection contractility imbalances between the left and right side Due to the fact that understanding mechanisms of pelvic floor muscle functioning is crucial in the therapy of pelvic floor dysfunctions, therefore, reliable, valid tests and instruments are important.

Vaginal palpation versus transabdominal ultrasound in the comprehension of pelvic floor muscle contraction after vaginal delivery: a randomised controlled trial

Background

Pelvic floor muscles support the pelvic organs and control voiding. The first choice in the repair of pelvic floor function that is damaged during pregnancy and delivery is pelvic floor muscle training, which involves repeated muscle relaxation and contraction. However, as muscle contractions cannot be visualised, it is difficult to assess whether patients understand how to contract them. Therefore, we assessed patients’ comprehension of pelvic floor muscle contraction by comparing two teaching methods, vaginal palpation and transabdominal ultrasound, following vaginal delivery. We hypothesised that vaginal palpation is better than transabdominal ultrasound in this regard.

Methods

This randomised controlled trial conducted in facilities in Tokyo, Japan between July 2018 and January 2019 included women aged ≥ 20 years at 4–6 weeks after vaginal delivery. The randomisation involved website-based centralised allocation. The primary outcome was a change in bladder base displacement during pelvic floor muscle contraction before and after training, which was measured using transabdominal ultrasound. Participants performed three contractions for 3 s, and the mean value was used for statistical analysis. The secondary outcome was a change in understanding the contraction before and after training, which was measured using a five-point Likert scale questionnaire. Outcomes were analysed using Welch’s t-test.

Results

Sixty-five participants were randomly allocated to the vaginal palpation group (n = 32) and transabdominal ultrasound group (n = 33). Baseline characteristics were similar between the groups. Changes in bladder base displacement were not significantly different between the groups (p = 0.181). Within-group analyses showed that bladder base displacement was large in both groups after the respective intervention. There were no significant differences in any of the outcomes between the two groups before and after the intervention.

Conclusions

Vaginal palpation and transabdominal ultrasound might be useful for comprehending pelvic floor muscle contraction after vaginal delivery.

Trial registration: UMIN 000032304. Registered 18 April 2018, https://upload.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000036820.

Novel insight into the coordination between pelvic floor muscles and the glottis through ultrasound imaging: a pilot study

INTRODUCTION

Pelvic floor physical therapists have long utilized breathing cues with exercises and are beginning to incorporate vocalization tasks. To date, there have been no publications describing pelvic floor displacement during vocalization tasks. This study is a preliminary investigation into the changes in bladder shape distortion as a proxy for pelvic floor muscle displacement during respiratory and phonatory tasks.

METHODS

Bladders were imaged using two-dimensional ultrasound in standing position. Measurement consisted of a diagonal line from the most anterior-superior aspect of the bladder to the most inferior-posterior aspect of the bladder. Length was measured at baseline and maximum distortion for each task. The first two tasks cued pelvic floor muscles to contract and then strain. Subsequent tasks only cued glottis function. A linear regression tested correlation between bladder distortion response to glottis tasks and cued pelvic floor tasks. The hypothesis was that diagonal would shorten with contraction, lengthen with strain, and follow a similar pattern seen in respiration for phonation tasks.

RESULTS

Ten asymptomatic participants (5 men, 5 women) showed bladder diagonal shortening when cuing pelvic floor contraction for all participants and lengthening for 7 of the 10 participants when cued to strain the pelvic floor. The response of bladder length change was variable for glottis tasks, trending toward lengthening and significantly different in response to contraction.

CONCLUSIONS

When cuing pelvic floor to contract, healthy individuals showed shortening of bladder length and most lengthened during strain. When cuing phonation and respiration tasks, there was a tendency toward bladder lengthening.

Pelvic floor muscle displacement during jumps in continent and incontinent women: An exploratory study

INTRODUCTION

The prevalence of stress urinary incontinence during high-impact activities is high. Enhanced comprehension of pelvic floor muscle (PFM) displacement and activity is clinically relevant for the development of specific approaches in rehabilitation. The aim of the study is to investigate and to compare PFM displacement between the continent and incontinent women during jumps.

METHODS

A cross-sectional, exploratory design was applied to investigate PFM displacement during drop jumps (DJ) and countermovement jumps (CMJ). PFM displacement was assessed in craniocaudal translation and forward-backward rotation with an electromagnetic tracking system.

RESULTS

Twenty-eight continent and 22 incontinent women were included. During the first landing of DJ, a primary caudal, during the second landing of DJ/CMJ a primary cranial translation and during all jump a primary backward rotation was observed. No significant difference between the groups was found.

DISCUSSION

PFM displacement during running demonstrated caudal translation/forward rotation before and cranial translation/backward rotation after heel strike. During the second landing of DJ/CMJ a cranial translation/backward rotation and during the first landing of DJ a caudal translation/backward rotation has been observed after ground contact. This may be due to the longer lasting bodyweight force in the first landing of DJ. No eccentric-concentric stretch-shortening cycle could be seen.

CONCLUSION

This study indicates that during jumps two opposite reactions of involuntary PFM displacement happen, but no stretch-shortening cycle with an eccentric-concentric contraction could be found. Jumping stimuli inducing involuntary PFM displacement should be used for future investigations to consider a beneficial effect concerning continence.