Pelvic floor muscle displacement during voluntary and involuntary activation in continent and incontinent women: a systematic review

Novel Method of Measuring Pelvic Floor Muscle Motion May Improve Accessibility of Pelvic Floor Muscle Coordination Training

INTRODUCTION AND HYPOTHESIS

Pelvic floor muscle ultrasound is an important clinical tool for improving motor coordination and even strength. Although the gold standard approach involves transperineal probe placement, this is not always feasible with sensitive populations, requires privacy owing to probe placement, and additional sonography training. This article introduces a novel transabdominal method for measuring pelvic floor muscle motion that incorporates a reference point within the bladder. The hypothesis is that the novel measurement will correlate positively with transperineal measurements.

METHODS

A total of 55 women (15 nulliparous, 40 parous; 20 continent, 35 incontinent) performed pelvic floor muscle contraction and strain. Transabdominal ultrasound measured bladder diagonal length (BDL) and transperineal ultrasound measured bladder neck height (BNH), levator plate length (LPL), and levator plate angle (LPA). Spearman's test measured the correlation between the measurement outcomes and an independent t test compared outcomes based on parity and stress urinary incontinence symptom status.

RESULTS

Spearman's correlation showed moderate positive correlations between the pelvic floor measurements for both tasks, which reduced slightly when grouping by parity and symptom status. Group differences were significant for BDL during the muscle contraction, factoring in SUI symptoms (p = 0.019) and parity status (p = 0.005) and LPL during contraction, factoring in parity status (p = 0.033).

CONCLUSIONS

BDL correlates with BNH, LPL, and LPA with slightly reduced correlation when factoring in parity and continence status. The advantages of the method include accessibility for sensitive populations, nontraditional positions due to the anatomical reference point, functional locations due to limited privacy needs, and minimal training required for pelvic floor therapists to incorporate into rehabilitation.

Can pelvic floor muscle function before surgery determine the outcome of surgical treatment of stress urinary incontinence in women?

AIM

The study aimed to determine whether pelvic floor muscle (PFM) function before surgery may correlate with the success of surgical interventions for treating stress urinary incontinence (SUI). Our hypothesis was that addressing identified variables in preoperative rehabilitation could potentially improve surgical outcomes.

METHODS

This prospective observational study was conducted at a single center and enrolled women qualified to mid-urethral tape insertion for SUI between 2020 and 2022. Digital palpation and manometry (Peritron™ 9300 V) were used to evaluate PFM function. The following parameters were acquired: vaginal resting pressure, vaginal pressure during maximal voluntary contraction (MVC), the area under the curve during a 10-second MVC, moreover the ability to perform correct PFM contraction, reflexive PFM contraction during cough and relaxation were assessed. All measurements were performed before the surgical treatment and during follow-up assessments at 1, 3, and 6 months postoperatively. The primary endpoint of the study was defined as objective cure, characterized by a negative cough stress test (CST), along with a subjective assessment based on the Urogenital Distress Inventory-6 (UDI-6) and Incontinence Impact Questionnaire-7 (IIQ-7).

RESULTS

The study involved 57 eligible female participants, all of whom completed the 6-month follow-up. Objective cure was observed in 75.44% of cases, while subjective cure was reported in 33%. There was no association between PFM parameters and surgical outcomes.

CONCLUSION

The success of surgical treatment of SUI 6 months postsurgery is not related to preoperative pelvic floor muscle function.

Impact of Urinary Incontinence on Physical Function and Respiratory Muscle Strength in Incontinent Women: A Comparative Study between Urinary Incontinent and Apparently Healthy Women

Patients with stress urinary incontinence (SUI) may be afraid to increase intra-abdominal pressure to avoid incontinence. This could lead to weak expiratory muscles. The aim of this study was to investigate the association between respiratory muscle strength, physical function, and SUI in patients with SUI. A cross-sectional study was conducted in the Physical Medicine and Functional Rehabilitation Department. Thirty-one incontinent women (IG) and twenty-nine women in a control group (CG) were enrolled in this study. Anthropometric data, respiratory muscle strength (maximal inspiratory pressure; maximal expiratory pressure), SUI (Urogenital Distress Inventory-6; Incontinence Impact Questionnaire-7; Pad test), and physical function (waist circumference; timed-up-and-go test; abdominal muscle strength) were assessed. Body fat, body mass index, body weight, and waist circumference were higher in IG than CG (p < 0.01), while postural gait and abdominal muscles were lower (p < 0.001). Respiratory muscle strength displayed moderate correlations with SUI severity, especially for maximal expiratory pressure (p < 0.01). Maximal expiratory pressure was moderately associated with physical function. Deterioration in respiratory muscle strength is a characteristic of women with SUI. In this population, pelvic floor muscle training may be prescribed to improve continence. By feeling more confident about increasing intra-abdominal pressure, women with SUI would strengthen their expiratory muscles and eventually improve their physical function.

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.

Involuntary reflexive pelvic floor muscle training in addition to standard training versus standard training alone for women with stress urinary incontinence: a randomized controlled trial

Introduction and hypothesis

Although involuntary reflexive pelvic floor muscle contractions seem crucial during stress urinary incontinence-provoking situations, hitherto existing guidelines feature voluntary pelvic floor muscle training only. Two pelvic floor muscle protocols were compared regarding their effect on stress urinary incontinence in women: one focusing on standard physiotherapy with voluntary pelvic floor muscle training, the other additionally including involuntary reflexive pelvic floor muscle training.

Methods

This study was designed as a triple-blind prospective randomized controlled trial with women suffering from stress urinary incontinence with two physiotherapy intervention groups (control group: standard physiotherapy, n = 48, experimental group: standard physiotherapy plus involuntary reflexive pelvic floor muscle training triggered by whole-body movements such as jumps n = 48). Both interventions lasted 16 weeks (9 personal physiotherapy consultations and 78 home training sessions). Group differences and development over time were analyzed concerning the primary outcome International Consultation on Incontinence Modular Questionnaire Urinary Incontinence short form (ICIQ-UIsf) by mixed effect regression models.

Results

The ICIQ-UIsf score decreased significantly over time for both groups by about 3 points from about 10 to about 7 points with no group differences at any point in time.

Discussion

This trial did not find any additional benefit for stress urinary incontinence by adding involuntary reflexive pelvic floor muscle training to standard training. Both training protocols showed similar clinically relevant improvements; however, there was still moderate incontinence after interventions. Future studies should test and apply pelvic floor muscle function-oriented training methods for pelvic floor muscle hypertrophy, intramuscular coordination, and power, which are more in line with conventional skeletal muscle training, i.e., performed with higher intensities and workout.

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.

An assessment of techniques and practices used to elevate intra-abdominal pressure when assessing pelvic floor dysfunction

AIMS

To determine terminology and methods for raising intra-abdominal pressure (IAP) currently used by clinicians to assess pelvic floor dysfunction (PFD) and to measure the effect of these maneuvers on IAP.

METHODS

Three-hundred questionnaires were distributed at two scientific meetings in the United Kingdom to determine methods clinicians used to raise IAP and their perceptions of these methods. Twenty healthy volunteers were also recruited to measure the effect of two methods of raising IAP: Valsalva maneuver (VM) and bear down maneuver (BDM). IAP pressure was measured with rectal catheters connected to pressure sensors. The IAP was measured during each maneuver in both standing and supine positions.

RESULTS

Maneuvers used in practice were cough (79%), BDM (60%), and VM (38%). 44% of clinicians felt patients found it difficult to raise their IAP. There was uncertainty among clinicians as to which method was the most effective in raising IAP and whether the different methods produced the same rise in IAP. On testing IAP in 20 healthy volunteers, median (interquartile range) IAP generated during BDM; 101 (59.1) cmH₂ O was significantly higher than that generated during VM; 80.3 (43.6) cmH₂ O (p < .0001).

CONCLUSION

Clinicians varied widely in the maneuvers they used to raise patients' IAP to test for PFD and there was uncertainty about the maneuvers' effect on IAP. In healthy volunteers, BDM produced significantly higher IAP than VM. We recommend standardization of terminology and techniques used to raise IAP when assessing PFD, to ensure consistency of diagnosis and assessment of treatment outcomes.

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.

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

INTRODUCTION AND HYPOTHESIS

Understanding the functioning of pelvic floor muscles (PFM) is crucial in female PFM rehabilitation. The aim of this study was to determine the intra-session retest reliability and validity to evaluate the quantity of PFM displacement.

METHODS

This cross-sectional observational study examined the PFM displacement of 17 young healthy nulliparous women in the midsagittal plane. Three maximal voluntary contractions (MVCs) and five fast voluntary contractions (FVCs) were simultaneously examined with an electromagnetic tracking system (ETS) and transabdominal ultrasound (TAUS) and expressed in millimeters (mean, SD). To evaluate reliability and validity, the analysis of variance, intraclass coefficient (2,1), standard error of measurement (SEM), and minimal detectable difference (MDD) were calculated.

RESULTS

Maximal voluntary contractions and FVCs in supine position measured by an ETS (TAUS) showed a displacement of MVC: 3.5 ± 1.9 mm (7.8 ± 4.5 mm), FVC: 3.5 ± 2.4 mm (7.6 ± 5.3 mm), and during standing of MVC: 5.2 ± 1.6 mm (9.4 ± 3.8 mm) and FVC: 4.8 ± 2.5 mm (9.7 ± 4.1 mm). Intraclass correlation for the ETS (TAUS) measurement varied between 0.79 and 0.89 (0.61 and 0.74), SEM 0.52 and 1.03 mm (1.54 and 3.2 mm), and MDD 1.54 and 3.2 mm (6.64 and 7.53 mm). The correlation between an ETS and TAUS varied between 0.53 and 0.67.

CONCLUSIONS

For MVC and FVC, ETS measurements are highly reliable and TAUS measurements are moderately reliable for both contraction types. The correlation between the TAUS and ETS measurements is moderate. An ETS seems to be a reliable and valid measurement tool for evaluating PFM displacement during voluntary contractions. In future studies, the reproducibility and validity of ETS measurements need to be investigated in impact activities.

Evaluation of pelvic floor kinematics in continent and incontinent women during running: An exploratory study

AIMS

Impact activity like running is associated with an increase in intra-abdominal pressure which needs to be sufficiently countered by pelvic floor muscle (PFM) activity to secure continence. The aim of this study was to investigate and compare PFM kinematics in continent and incontinent women during running.

METHOS

Three-dimensional position and orientation was measured with the electromagnetic tracking device trakSTAR™. One sensor was attached to the vaginal probe and a second one was secured to the subjects' skin at the height of the second sacral vertebrae. Cranial-caudal and forward-backward displacement of the vaginal probe was measured during 10 sec running on a treadmill at the speeds 7, 11, and 15 km/h. Displacement data from 100 ms before to 300 ms after heel-strike were analyzed.

RESULTS

Nineteen incontinent and twenty-seven continent women were included in this study. Before the foot touched the ground caudal translation and forward rotation of the vaginal probe was detected, whereas after heel-strike a cranial translation and backward rotation was measured. Cranial-caudal translation as well as backward-forward-rotation did not differ significantly between continent and incontinent subjects for the three speeds. Analysis of maximum displacements showed significantly increasing displacement with increasing speeds.

CONCLUSIONS

Kinematic measurements during impact activity of running demonstrated caudal translation before and cranial translation after heel-strike. The hypothesis of caudal translation through impact activity was not confirmed. Patterns seem similar between continent and incontinent subjects. Associations between the direction of displacement and muscle action of PFMs remain assumptions.