Dynamics of male pelvic floor muscle contraction observed with transperineal ultrasound imaging differ between voluntary and evoked coughs

Pelvic floor muscle length changes with breathing in males: A preliminary report

The study aimed to identify whether pelvic floor muscles modulate length with breathing, and if any length changes induced by breathing relate to abdominal cavity displacement and intra-abdominal pressure. To investigate these relationships, displacement of pelvic landmarks that related to pelvic floor muscle length using transperineal ultrasound imaging, breath volume, intra-abdominal pressure, abdominal and ribcage displacement, and abdominal and anal sphincter muscle electromyography were measured during quiet breathing and breathing with increased dead-space in ten healthy men. Pelvic floor muscle landmark displacement modulated with ribcage motion during breathing. This relationship was stronger for: i) motion of the urethrovesical junction (puborectalis muscle length change) than the mid-urethra landmark (striated urethral sphincter muscle length change), and ii) dead-space breathing in standing than dead-space breathing in supine or quiet breathing in standing. In most (but not all) participants, the urethrovesical junction descended during inspiration and elevated during expiration. Striated urethral sphincter length changes during the respiratory cycle was independent of intra-abdominal pressure. In summary, breathing involves pelvic floor muscle length changes and is consistent with the role of these muscles during respiration to aid maintenance of continence, lung ventilation and/or provision of support to the abdominal cavity. Clinicians who train pelvic floor muscles need to be aware that length change of pelvic floor muscles is expected with breathing.

Lateral abdominal muscle thickness during breathing maneuvers in women with and without stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) patients predominantly experience involuntary leakage during respiratory functions that induce a rapid increase in intra-abdominal pressure (IAP) such as coughing and sneezing. The abdominal muscles have an important role in the forced expiration and modulation of IAP. We hypothesized that SUI patients have different thickness changes in the abdominal muscles compared to healthy individuals during breathing maneuvers.

METHODS

This case-control study was conducted on 17 adult women with SUI and 20 continent women. Muscle thickness changes were measured by ultrasonography at the end of deep inspiration and expiration, and the expiratory phase of voluntary coughing for external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) muscles. The percent thickness changes of muscles were used and analyzed with a two-way mixed ANOVA test and post-hoc pairwise comparison at a confidence level of 95% (p < 0.05).

RESULTS

The percent thickness changes of TrA muscle were significantly lower in SUI patients at deep expiration (p < 0.001, Cohen's d = 2.055) and coughing (p < 0.001, Cohen's d=1.691). While, percent thickness changes for EO (p = 0.004, Cohen's d=0.996) and IO thickness (p < 0.001, Cohen's d=1.784) were greater at deep expiration and deep inspiration, respectively.

CONCLUSIONS

The percent thickness changes of abdominal muscles differed between women with and without SUI during breathing maneuvers. The present study provided information regarding the altered function of abdominal muscles during breathing maneuvers; therefore, it is important to consider the respiratory role of abdominal muscles for the rehabilitation of SUI patients.

Preoperative exercise interventions to optimize continence outcomes following radical prostatectomy

Urinary incontinence is a common and predictable consequence among men with localized prostate cancer who have undergone radical prostatectomy. Despite advances in the surgical technique, urinary continence recovery time remains variable. A range of surgical and patient-related risk factors contributing to urinary incontinence after radical prostatectomy have been described, including age, BMI, membranous urethral length and urethral sphincter insufficiency. Physical activity interventions incorporating aerobic exercise, resistance training and pelvic floor muscle training programmes can positively influence the return to continence in men after radical prostatectomy. Traditional approaches to improving urinary continence after radical prostatectomy have typically focused on interventions delivered during the postoperative period (rehabilitation). However, the limited efficacy of these postoperative approaches has led to a shift from the traditional reactive model of care to more comprehensive interventions incorporating exercise-based programmes that begin in the preoperative period (prehabilitation) and continue after surgery. Comprehensive prehabilitation interventions include appropriately prescribed aerobic exercise, resistance training and specific pelvic floor muscle instruction and exercise training programmes. Transperineal ultrasonography is a non-invasive and validated method for the visualization of the action of the pelvic floor musculature, providing real-time visual biofeedback to the patient during specific pelvic floor muscle instruction and training. Importantly, the waiting time before surgery can be used for the delivery of comprehensive prehabilitation exercise-based interventions to increase patient preparedness in the lead-up to surgery and optimize continence and health-related quality-of-life outcomes following radical prostatectomy.

Novel insight into pressurization of the male and female urethra through application of a multi-channel fibre-optic pressure transducer: Proof of concept and validation

Purpose

To confirm feasibility of recording pressure along the length of the urethra using a multi-sensor fibre-optic pressure catheter; to identify the spatial and temporal features of changes in pressure along the urethra at sites related to specific striated pelvic floor muscles; and to investigate the relationship between urethral pressures and activation of individual pelvic floor muscles estimated from ultrasound imaging.

Materials and Methods

Proof-of-concept study including one male (47 years old) and one female (33 years old). A multi-sensor fibre optic pressure catheter (10 mm sensor separation) was inserted into the urethra. Pressure data were recorded simultaneously with trans-perineal ultrasound imaging measures of pelvic floor muscle activity during sub-maximal and maximal voluntary contractions and evoked coughs.

Results

Pressure changes along the urethra were recorded in all tasks in both participants. Face validity of interpretation of pressure measures with respect to individual muscles was supported by correlation with ultrasound-measured displacements induced by the relevant muscles. Onset of pressure increase occurred in a distal to proximal sequence in the urethra of the male but not the female during voluntary contraction. Peak urethral pressures varied in location, timing and amplitude between tasks. Evoked cough induced in the greatest urethral pressure increase across all tasks for both participants.

Conclusions

The high spatial resolution pressure catheter provide viable and valid recordings of urethral pressure in a male and female. Data provide preliminary evidence of sex differences in spatial and temporal distribution of urethral pressure changes.

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.

Influence of body position on dynamics of the pelvic floor measured with transperineal ultrasound imaging in men

AIMS

This paper aims to evaluate the feasibility of transperineal ultrasound imaging (TPUS) for visualizing the motion of pelvic landmarks associated with striated pelvic floor muscle contraction in men in standing; to compare the locations of pelvic landmarks between sitting and standing; and to compare the effects of different body positions on measures of pelvic floor muscle contraction.

METHODS

Thirty-five men awaiting prostatectomy volunteered to participate. Participants performed three repetitions of submaximal pelvic floor contraction in sitting and again in standing. Movement of pelvic landmarks with contraction was recorded using an ultrasound imaging transducer placed on the perineum.

RESULTS

The feasibility of TPUS in men in standing was demonstrated through the visualization of three out of four pelvic landmarks in more than 95% of images in the standing position. Analysis of pelvic landmarks and their respective relationships with muscle shortening demonstrated that the anorectal junction and urethrovesical junction were lower and the estimated length of puborectalis was shorter in standing than sitting. The mid-urethra (striated urethral sphincter) and anorectal junction (puborectalis) landmark displaced further cranially in standing than sitting.

CONCLUSIONS

TPUS can be used to visualize three pelvic landmarks in men with cancerous prostates. Puborectalis is shorter at rest in standing than sitting, and elevation of the mid-urethra and the anorectal junction is more in standing than sitting. Together these findings indicate that feedback for pelvic floor muscle training is possible in both positions, but the position needs to be standardized for a comparative assessment.

Reconsideration of pelvic floor muscle training to prevent and treat incontinence after radical prostatectomy

Urinary incontinence is common after radical prostatectomy. Pelvic floor muscle training provides a plausible solution. Although early trials provided promising results, systematic reviews have questioned the efficacy of this intervention. A major consideration is that most clinical trials in men have applied principles developed for pelvic floor muscle training for stress urinary incontinence in women, despite differences in anatomy between sexes and differences in the mechanisms for continence/incontinence. Literature regarding continence control in men has been conflicting and often based on erroneous anatomy. New understanding of continence mechanisms in men, including the complex contribution of multiple layers of striated pelvic floor muscles, and detailed consideration of the impact of radical prostatectomy on continence anatomy and physiology, have provided foundations for a new approach to pelvic floor muscle training to prevent and treat incontinence after prostatectomy. An approach to training can be designed to target the pathophysiology of incontinence. This approach relies on principles of motor learning and exercise physiology, in a manner that is tailored to the individual patient. The aims of this review are to consider new understanding of continence control in men, the mechanisms for incontinence after radical prostatectomy, and to review the characteristics of a pelvic floor muscle training program designed to specifically target recovery of continence after prostatectomy.

Efficacy of a personalised pelvic floor muscle training programme on urinary incontinence after radical prostatectomy (MaTchUP): protocol for a randomised controlled trial

INTRODUCTION

Prostate cancer is the most common cancer in men. Prostatectomy is the most common treatment. Morbidity from prostatectomy is high-80% of men experience urinary incontinence which negatively impacts the quality of life. Postsurgical pelvic floor muscle training is commonly prescribed but recent systematic reviews found no evidence of efficacy. We propose a new treatment that commences preoperatively and targets functional training of specific pelvic floor muscles that contribute to urinary continence. Assessment and biofeedback using transperineal ultrasound imaging assists in training. This will be compared against conventional training (maximal pelvic floor muscle contraction assessed by digital rectal examination) and no training. Embedded physiological studies will allow the investigation of moderation and mediation of the treatment effect on the outcomes.

METHODS AND ANALYSIS

This randomised clinical trial will include 363 men scheduled to undergo radical prostatectomy for prostate cancer. Participants will be randomised into urethral training, conventional training and no training groups. Clinical data will be collected at baseline (1-2 weeks presurgery) and postsurgery after catheter removal, weekly to 3 months (primary endpoint) and monthly to 12 months. Outcomes include 24-hour pad weight test (primary), incontinence, quality of life and cost-effectiveness data. Neuromuscular control measures of pelvic floor muscles will be measured at baseline, postsurgery, 6 weeks, 3 and 12 months. Study assessors and statisticians will be blinded to the group allocation.

ETHICS AND DISSEMINATION

This study is registered with the Australian New Zealand Clinical Trials Registry and has ethical approval from the university and host hospital ethics committees. Trial outcomes will be shared via national/international conference presentations and peer-reviewed journal publications.

TRIAL REGISTRATION NUMBER

ACTRN12617000788370; Pre-results.

Task-specific differences in respiration-related activation of deep and superficial pelvic floor muscles

The female pelvic floor muscles (PFM) are arranged in distinct superficial and deep layers that function to support the pelvic/abdominal organs and maintain continence, but with some potential differences in function. Although general recordings of PFM activity show amplitude modulation in conjunction with fluctuation in intra-abdominal pressure such as that associated with respiration, it is unclear whether the activities of the two PFM layers modulate in a similar manner. This study aimed to investigate the activation of the deep and superficial PFM during a range of respiratory tasks in different postures. Twelve women without pelvic floor dysfunction participated. A custom-built surface electromyography (EMG) electrode was used to record the activation of the superficial and deep PFM during quiet breathing, breathing with increased dead space, coughing, and maximal and submaximal inspiratory and expiratory efforts. As breathing demand increased, the deep PFM layer EMG had greater coherence with respiratory airflow at the frequency of respiration than the superficial PFM (P = 0.038). During cough, the superficial PFM activated earlier than the deep PFM in the sitting position (P = 0.043). In contrast, during maximal and submaximal inspiratory and expiratory efforts, the superficial PFM EMG was greater than that for the deep PFM (P = 0.011). These data show that both layers of PFM are activated during both inspiration and expiration, but with a bias to greater activation in expiratory tasks/phases. Activation of the deep and superficial PFM layers differed in most of the respiratory tasks, but there was no consistent bias to one muscle layer. NEW & NOTEWORTHY Although pelvic floor muscles are generally considered as a single entity, deep and superficial layers have different anatomies and biomechanics. Here we show task-specific differences in recruitment between layers during respiratory tasks in women. The deep layer was more tightly modulated with respiration than the superficial layer, but activation of the superficial layer was greater during maximal/submaximal occluded respiratory efforts and earlier during cough. These data highlight tightly coordinated recruitment of discrete pelvic floor muscles for respiration.

Postprostatectomy incontinence is related to pelvic floor displacements observed with trans-perineal ultrasound imaging

AIMS

To investigate the relationship between post-prostatectomy incontinence and dynamic features of activation of specific pelvic floor muscles in addition to anatomical parameters of the urethra.

METHODS

Forty-two men aged 66 (7) years (incontinent [N = 19] and continent [N = 23]) who had undergone prostatectomy participated. Transperineal ultrasound imaging was used to record sagittal images of pelvic structures during involuntary coughing and sustained maximal voluntary contractions. Imaging data were analyzed to calculate displacements of pelvic floor landmarks associated with activation of the puborectalis, striated urethral sphincter, and bulbocavernosus muscles. Anatomical features of functional urethral length and the resting position of the ano-rectal and urethra-vesical junctions were calculated. A principal component analysis and multiple logistic regression were used to consider which combinations of variables best distinguish between men with and without incontinence.

RESULTS

Five principal components were identified that together explained 72.0% of the data. Two principal components that represented (i) striated urethral sphincter activation and (ii) bulbocavernosus and puborectalis muscle activation were significantly different between participants with and without incontinence. Together these components correctly identified 88.1% of incontinent men, with a specificity and sensitivity of 91.3% and 84.2%, respectively. Poor function of the bulbocavernosus and puborectalis muscles could be compensated by good striated urethral sphincter function, but the bulbocavernosus and puborectalis muscles had less potential to compensate for poor striated urethral sphincter function.

CONCLUSIONS

Dynamic features of pelvic floor muscle activation, particularly shortening of the striated urethral sphincter during cough and voluntary contraction, are related to continence status after prostatectomy.

Validity of Estimation of Pelvic Floor Muscle Activity from Transperineal Ultrasound Imaging in Men

PURPOSE

To investigate the relationship between displacement of pelvic floor landmarks observed with transperineal ultrasound imaging and electromyography of the muscles hypothesised to cause the displacements.

MATERIALS AND METHODS

Three healthy men participated in this study, which included ultrasound imaging of the mid-urethra, urethra-vesical junction, ano-rectal junction and bulb of the penis. Fine-wire electromyography electrodes were inserted into the puborectalis and bulbocavernosus muscles and a transurethral catheter electrode recorded striated urethral sphincter electromyography. A nasogastric sensor recorded intra-abdominal pressure. Tasks included submaximal and maximal voluntary contractions, and Valsalva. The relationship between each of the parameters measured from ultrasound images and electromyography or intra-abdominal pressure amplitudes was described with nonlinear regression.

RESULTS

Strong, non-linear relationships were calculated for each predicted landmark/muscle pair for submaximal contractions (R2-0.87-0.95). The relationships between mid-urethral displacement and striated urethral sphincter electromyography, and bulb of the penis displacement and bulbocavernosus electromyography were strong during maximal contractions (R2-0.74-0.88). Increased intra-abdominal pressure prevented shortening of puborectalis, which resulted in weak relationships between electromyography and anorectal and urethravesical junction displacement during all tasks.

CONCLUSIONS

Displacement of landmarks in transperineal ultrasound imaging provides meaningful measures of activation of individual pelvic floor muscles in men during voluntary contractions. This method may aid assessment of muscle function or feedback for training.

Pelvic floor muscle function is an independent predictor of outcome after retrourethral transobturator male sling procedure

PURPOSE

To evaluate the impact of the retrourethral transobturator sling (RTS) on pelvic floor muscle function (PFMF) and whether preoperative PFMF is associated with RTS outcome.

METHODS

Between May 2008 and December 2010, 59 consecutive men with postprostatectomy stress urinary incontinence (PSUI) underwent PFMF assessment before RTS and 6 months thereafter in a prospective cohort study. The assessments included demographic and clinical characteristics, and quality of life (QoL) questionnaires. PFMF was evaluated by digital rectal examination on the modified 6-point Oxford scale and by surface electromyography. The primary outcome measurement was success after RTS defined as PSUI cure with use of no or one dry "security" pad. For secondary outcome, PFMF, 1-h pad test, and impact of PSUI on QoL were evaluated. Uni- and multivariate analyses were performed.

RESULTS

After 6-month follow-up, the cure, improvement (>50 % pad reduction) and failure rates were 50 % (29/58 patients), 24 % (14/58 patients) and 26 % (15/58 patients), respectively. Significant improvement of QoL, clinical and PFMF parameters occurred after RTS. On multivariate analysis, weak PFMF (OR 86.29) and greater muscle fatigue (OR 3.31) were significant independent predictors of RTS failure. The final model demonstrated good calibration (p = 0.882) and excellent discriminative ability (0.942, 95 % CI 0.883-1.0) to predict success after RTS.

CONCLUSIONS

PFMF improved significantly after RTS procedure. Higher muscle fatigue and weak PFMF were independent predictors of RTS failure. Digital rectal evaluation of PFMF is a simple and reliable clinical tool, which can be used by urologists in daily routine to predict the RTS outcome.