Modern Theories of Pelvic Floor Support : A Topical Review of Modern Studies on Structural and Functional Pelvic Floor Support from Medical Imaging, Computational Modeling, and Electromyographic Perspectives

Potential role of physical labor and cultural views of menstruation in high incidence of pelvic organ prolapse in Nepalese women: a comparative study across the menstrual cycle

Introduction

Pelvic organ prolapse (POP) is a significant health concern for young Nepali women, with potential risk factors including pelvic floor trauma from vaginal delivery and heavy lifting. The prevalence of symptomatic POP (SPOP) among nulliparous women in Nepal is 6%, while the general population of Nepali women aged 15-49 years reports a prevalence of 7%. Surprisingly, the average age of SPOP onset in Nepal is 27 years, challenging the assumption that postmenopausal age and vaginal delivery are the sole risk factors. This study aims to investigate the influence of increased intra-abdominal pressure (IAP) during lifting tasks on pelvic organ descent in Nepali women across different menstrual cycle stages.

Methods

The study included 22 asymptomatic Nepali women aged 18-30 years who regularly engage in heavy lifting. Intra-abdominal pressure was measured intra-vaginally during typical and simulated lifting tasks, which encompassed various scenarios such as ballistic lifting, ramped lifting, and pre-contraction of pelvic floor muscles, as well as coughing, Valsalva maneuver, and pelvic floor contractions. Pelvic floor displacement was recorded using transperineal ultrasound during menstruation, ovulation, and the mid-luteal phase.

Results

Results indicated that pelvic floor displacement was greater during menstruation than ovulation when performing a simulated ballistic lifting task (6.0 ± 1.6 mm vs. 5.1 ± 1.5 mm, p = 0.03, d = 0.6). However, there was no significant difference in pelvic floor displacement during lifting when the pelvic muscles were pre-contracted.

Conclusion

These findings suggest that lifting heavy loads during menstruation may increase the risk of stretching and injuring pelvic floor supportive tissues, potentially contributing to SPOP in young Nepali women. Pre-contracting pelvic floor muscles during lifting tasks may offer a protective effect. Understanding these factors could aid in developing targeted preventive measures and raising awareness about the impact of heavy lifting on pelvic floor health among Nepali women.

Analysis of the anatomical and biomechanical characteristics of the pelvic floor in cystocele

INTRODUCTION

Stress urinary incontinence (SUI) occurs due to disruption of the pelvic floor anatomy; however, the complexity of the pelvic floor support structures and individual patient differences make it difficult to identify the weak points in the pelvic floor support that cause SUI to occur, develop, and recur. This study aimed to analyze the pelvic floor anatomy, structural features, and biomechanics of cystoceles to develop more effective treatment plans with individualized and precise healthcare.

MATERIAL AND METHODS

In this observational case-controlled study (clinical trial identifier BOJI201855L), 102 women with normal pelvic floor function and 273 patients diagnosed with cystocele degrees I-III were identified at Shanghai General Hospital from October 2016 to December 2019. We combined ultrasound and vaginal tactile imaging (VTI) to assess the anatomy and biomechanical functions of the anterior and posterior vaginal walls. Both examinations included relaxation and muscle tension tests.

RESULTS

Of the 42 VTI parameters, 13 were associated with the degree of cystocele, six with an increase in the urethral rotation angle (pointing to the mobility of the urethra), and six with a decrease in the retrovesical angle (pointing to hypsokinesis and decrease in bladder position). According to these data, the strength of tissues, especially the muscles in both the anterior and posterior compartments, contributes to the stability of the pelvic floor structure. The strength of the levator ani muscle (LAM) is important for the degree of cystocele, mobility of the urethra, hypsokinesis, and decrease in bladder position.

CONCLUSIONS

In general, the biomechanical status of the pelvic floor in patients with cystocele is complex and involves various muscles, ligaments, tendons, and fascia. Of these, repair and exercise of the LAM have not received much attention in the treatment of patients with cystoceles, which may be an important risk factor for the high recurrence rate.

Platelet-rich Plasma Promotes Restoration of the Anterior Vaginal Wall for the Treatment of Pelvic Floor Dysfunction in Rats

STUDY OBJECTIVE

To determine the efficacy of using platelet-rich plasma (PRP) for vaginal wall repair in rats with vaginal wall impairment induced by vaginal distension (VD).

DESIGN

A single-blind, randomized study.

SETTING

A certified animal research facility.

ANIMALS

Twenty-four female Sprague Dawley rats.

INTERVENTIONS

Female Sprague Dawley rats were divided into sham (n = 8), VD (n = 8), and VD + PRP (n = 8) groups. Vaginal tissues from the VD group were dissected at 28-day post injury. VD + PRP rats received vaginal PRP injections on the 1st, 7th, 14th, and 21st day after VD and sacrificed on the 28th day.

MEASUREMENTS AND MAIN RESULTS

Urodynamic tests were performed in all rats. Immunohistochemistry was used to evaluate matrix metalloprotease-2 (MMP-2) and matrix metalloprotease-9 (MMP-9). Masson's staining was used to evaluate collagen fibers and calculate collagen volume fraction. Collagen fiber damage was confirmed in the VD group, evidenced by thinner and sparse distribution of collagen fibers, with significantly higher MMP-2 and MMP-9 expression than the sham group (p <.05). The collagen fiber damage in the vaginal wall likely led to pelvic floor dysfunction (PFD), evidenced by significantly decreased bladder leak-point pressure (p <.01) and abdominal leak-point pressure (p <.01) in the VD group compared with the sham group. After completion of the PRP treatment, a significantly higher collagen volume fraction (p <.01) and significantly increased bladder leak-point pressure (p <.05) and abdominal leak-point pressure (p <.01) were achieved in the VD + PRP compared with the VD group, thus indicating repair of the vaginal wall and improvement of PFD.

CONCLUSION

PRP injections facilitate the regeneration of vaginal wall tissue, particularly collagen fiber, after VD, leading to functional improvement of PFD. Findings support the feasibility of using PRP as a novel treatment for PFD.

Treatment with platelet-rich plasma attenuates proprioceptor abnormalities in a rat model of postpartum stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) is the most prevalent form of urinary incontinence, and vaginal delivery is a major risk factor for developing SUI. We evaluated the hypothesis that applying the autologous platelet rich plasma (PRP) to the pelvic floor muscles via injection affects expression of proprioceptors and improves postpartum stress urinary incontinence (PSUI) in rats.

METHODS

Virgin female Sprague-Dawley rats were divided into control (n = 10) and experimental group(n = 20). Vaginal dilation was used to establish PSUI, and the rats in the experimental group were further divided into the PSUI group (n = 10) and PSUI+PRP group (n = 10). Pelvic floor muscles from rats in the PSUI+PRP group were positioned under ultrasound guidance for PRP injection. The morphology and number of pelvic floor muscle spindles were assessed using H&E staining, proprioceptors evaluated by gold chloride staining, and changes in the expression of neurotrophin-3 (NT-3) and skeletal myosin MY-32 determined by immunohistochemistry.

RESULTS

After 28 days,bladder leak point pressure (BLPP) and abdominal leaking-urine point pressure (ALPP) in rats with PSUI were significantly lower than in control animals (P<0.01). Both BLPP and ALPP increased significantly in the PSUI+PRP group (P<0.01). Compared with the control group, muscle spindle morphology and structure in the PSUI and PSUI+PRP groups had different pathological changes,with higher variations in the PSUI group. The positive signals for NT-3/MY-32 expression in control rats were higher than those from PSUI or PSUI+PRP groups, however, the expression for NT-3/MY-32 in PSUI+PRP animals was higher than that seen in the PSUI group (P < 0.01).

CONCLUSIONS

PSUI rats have an abnormal expression of pelvic proprioceptors, which affect proprioceptive function, and further the contractibility of pelvic floor muscles. A PRP injection may restore the sensory function of pelvic proprioceptors, thus improving urine leakage in PSUI rats.

Pelvic floor tissue damping during running using an intra-vaginal accelerometry approach

BACKGROUND

While cumulative loading of the pelvic floor during exercise appears to increase the risk of developing pelvic floor disorders, the pathophysiologic role of pelvic floor loading is poorly understood. The aim of this exploratory study was to present a method for evaluating vibrational frequency damping of the female pelvic floor and to investigate the potential utility of this approach in a preliminary evaluation.

METHODS

Female participants were instrumented with an intravaginal accelerometer and a hip-mounted accelerometer, then ran on a treadmill at 7 km/h and 10 km/h both before and after a 30-min self-selected pace. Displacement of the pelvic floor relative to the bony pelvis was calculated using double integration of the accelerometer data. Vibrational damping coefficients were calculated using a wavelet-based approach to determine the effect of continence status, parity, running speed and time on vibrational damping.

FINDINGS

Seventeen women (n = 10 reported regularly leaking urine while exercising, while n = 7 reported not leaking) completed the running protocol. No differences in vibrational damping were detected between continent and incontinent women when all frequency bands were evaluated together, however significant effects of parity, time, running speed and continence status were found within specific frequency bands. Parous women demonstrated less damping in the 25-40 Hz band compared to nulliparae, damping in the 13-16 Hz band was lower after the 30-min run, and incontinent women demonstrated lower damping in the 4.5-5.5 Hz band than continent women when running at 7 km/h.

INTERPRETATION

Intra-vaginal vibrational damping may be useful in detecting biomechanical mechanisms associated with pelvic floor disorders experienced by females during exercise.

Assessment of the Effectiveness of the Sonofeedback Method in the Treatment of Stress Urinary Incontinence in Women-Preliminary Report

Urinary incontinence is a common problem that affects postmenopausal women. This ailment has a negative impact on many aspects of life, significantly limiting everyday functioning related to professional work, physical activity or the intimate sphere. The aim of the study was to assess the effectiveness of the sonofeedback method in reducing the severity of urinary incontinence in postmenopausal women with a urinary incontinence problem. A total of 60 patients aged 45–65 with stress urinary incontinence, confirmed by a gynecologist, were qualified for the study. All persons qualified for the study were randomly assigned to study group A (n = 20), comparative B (n = 20) and control C (n = 20). Patients from group A were treated with sonofeedback of the pelvic floor muscles. In group B, the combined electrostimulation method was used with biofeedback training. Group C was a control group in which only the measured parameters were measured at the same time interval as those carried out in groups A and B. In all patients, three times: before the therapy, after the fifth procedure and after the end of the therapy, the incidence and severity of stress urinary incontinence were assessed—Gaudenz questionnaire and the intensity of urinary incontinence—a modified 1 h pad test. The obtained results have an application value giving the possibility of using effective therapy with sonofeedback in women in whom the recommended electrostimulation method cannot be used due to health and behavioral reasons.

Urinary Incontinence in Women: Modern Methods of Physiotherapy as a Support for Surgical Treatment or Independent Therapy

Urinary incontinence (UI) is a common health problem affecting quality of life of nearly 420 million people, both women and men. Pelvic floor muscle (PFM) training and other physiotherapy techniques play an important role in non-surgical UI treatment, but their therapeutic effectiveness is limited to slight or moderate severity of UI. Higher UI severity requires surgical procedures with pre- and post-operative physiotherapy. Given that nearly 30%-40% of women without dysfunction and about 70% with pelvic floor dysfunction are unable to perform a correct PFM contraction, therefore, it is particularly important to implement physiotherapeutic techniques aimed at early activation of PFM. Presently, UI physiotherapy focuses primarily on PFM therapy and its proper cooperation with synergistic muscles, the respiratory diaphragm, and correction of improper everyday habits for better pelvic organ support and continence. The purpose of this work is a systematic review showing the possibilities of using physiotherapeutic techniques in the treatment of UI in women with attention to the techniques of PFM activation. Evidence of the effectiveness of well-known (e.g., PFM training, biofeedback, and electrostimulation) and less-known (e.g., magnetostimulation, vibration training) techniques will be presented here regarding the treatment of symptoms of urinary incontinence in women.

A computational analysis of the effect of supporting organs on predicted vesical pressure in stress urinary incontinence

Stress urinary incontinence (SUI) or urine leakage from urethra occurs due to an increase in abdominal pressure resulting from stress like a cough or jumping height. SUI is more frequent among post-menopausal women. In the absence of bladder contraction, vesical pressure exceeds urethral pressure leading to urine leakage. The main aim of this study is to utilize fluid-structure interaction techniques to model bladder and urethra computationally under an external pressure like sneezing. Both models have been developed with linear elastic properties for the bladder wall while the patient model has also been simulated utilizing the Mooney-Rivlin solid model. The results show a good agreement between the clinical data and the predicted values of the computational models, specifically the pressure at the center of the bladder. There is 1.3% difference between the predicted vesical pressure and the vesical pressure obtained from urodynamic tests. It can be concluded that the accuracy of the predicted pressure in the center of the bladder is significantly higher for the simulation assuming nonlinear material property (hyperelastic) for the bladder in comparison to the accuracy of the linear elastic model. The model is beneficial for exploring treatment solutions for SUI disorder. Graphical abstract ^{3D processing of bladder deformation during abdominal pressure of a the physiological model and b the pathological model (starting from left to right and up to down, consecutively)}.

Multimodal imaging assessment and histologic correlation of the female rat pelvic floor muscles' anatomy

Pelvic floor disorders negatively impact millions of women worldwide. Although there is a strong epidemiological association with childbirth, the mechanisms leading to the dysfunction of the integral constituents of the female pelvic floor, including pelvic floor skeletal muscles, are not well understood. This is in part due to the constraints associated with directly probing these muscles, which are located deep in the pelvis. Thus, experimental models and non-invasive techniques are essential for advancing knowledge of various phenotypes of pelvic floor muscle injury and pathogenesis of muscle dysfunction, as well as developing minimally invasive approaches for the delivery of novel therapeutics. The most widely used animal model for pelvic floor disorders is the rat. However, the radiological anatomy of rat pelvic floor muscles has not been described. To remedy this gap, the current study provides the first detailed description of the female rat pelvic floor muscles' radiological appearance on MR and ultrasound images, validated by correlation with gross anatomy and histology. We also demonstrate that ultrasound guidance can be used to target rat pelvic floor muscles for possible interventional therapies.

Effect of different delivery modes on the short-term strength of the pelvic floor muscle in Chinese primipara

BACKGROUND

To investigate the effect of different delivery modes and related obstetric factors on the short-term strength of the pelvic floor muscle after delivery in Chinese primipara.

METHODS

A total of 4769 healthy Chinese primiparas at postpartum 6-8 weeks were interviewed. According to the difference of delivery mode, the selected primiparas were divided into 2 groups, including cesarean delivery group containing 2020 and vaginal delivery group containing 2749. All the vaginal deliveries were further divided into 3 groups, including episiotomy group containing 2279, perineal laceration group containing 398, and forceps assisted group containing72. The scales of their pelvic floor muscle (PFM) strengths were examined by specially trained personnel using digital palpation (Modified Oxford scale:0-5 grade). According to participants' willingness, if the PFM strength was weak (0 or 1 grade), at-home PFM training would be recommended and an electrical stimulation combined with biofeedback therapy would be conducted for them in hospital. Twelve weeks after delivery, the PFM strength would be measured again. For statistical analysis, t-test, one-way variance analysis, Chi-square analysis, Kruskal-Wallis test H, Mann-Whitney U test and Wilcoxon test were carried out.

RESULTS

The PFM strength in cesarean delivery group was higher than in vaginal delivery group (p < 0.05). Among 3 vaginal delivery groups, the PFM strength in perineal laceration group was the highest (p < 0.05); however, there was no difference in PFM strength between episiotomy group and forceps assisted group (p>0.05). After accepting PFM training at home and therapy in hospital, 305 women showed increased PFM strength (p < 0.05).

CONCLUSIONS

Vaginal delivery is an independent risk factor causing the damage of PFM, and episiotomy may cause injury of PFM. Through PFM training at home and therapy in hospital, those damage will resume as soon as possible in the short-time period after delivery.