Intra-abdominal Pressure and Pelvic Floor Health: Should We Be Thinking About This Relationship Differently?

Technologies for Evaluation of Pelvic Floor Functionality: A Systematic Review

Pelvic floor dysfunction is a common problem in women and has a negative impact on their quality of life. The aim of this review was to provide a general overview of the current state of technology used to assess pelvic floor functionality. It also provides literature research of the physiological and anatomical factors that correlate with pelvic floor health. This systematic review was conducted according to the PRISMA guidelines. The PubMed, ScienceDirect, Cochrane Library, and IEEE databases were searched for publications on sensor technology for the assessment of pelvic floor functionality. Anatomical and physiological parameters were identified through a manual search. In the systematic review, 114 publications were included. Twelve different sensor technologies were identified. Information on the obtained parameters, sensor position, test activities, and subject characteristics was prepared in tabular form from each publication. A total of 16 anatomical and physiological parameters influencing pelvic floor health were identified in 17 published studies and ranked for their statistical significance. Taken together, this review could serve as a basis for the development of novel sensors which could allow for quantifiable prevention and diagnosis, as well as particularized documentation of rehabilitation processes related to pelvic floor dysfunctions.

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.

Intrinsic factors contributing to elevated intra-abdominal pressure

Pelvic floor disorders affect 24% of US women, and elevated intra-abdominal pressure may cause pelvic injury through musculoskeletal strain. Activity restrictions meant to reduce pelvic strain after traumatic events, such as childbirth, have shown little benefit to patients. Reported high variability in abdominal pressure suggests that technique plays a substantial role in pressure generation. Understanding these techniques could inform evidence-based recommendations for protective pelvic care. We hypothesized use of a motion-capture methodology could identify four major contributors to elevated pressure: gravity, acceleration, abdominal muscle contraction, and respiration. Twelve women completed nineteen activities while instrumented for whole body motion capture, abdominal pressure, hip acceleration, and respiration volume. Correlation and partial least squares regression were utilized to determine primary technique factors that increase abdominal pressure. The partial least squares model identified two principal components that explained 59.63% of relative intra-abdominal pressure variability. The first component was primarily loaded by hip acceleration and relative respiration volume, and the second component was primarily loaded by flexion moments of the abdomen and thorax. While reducing abdominal muscle use has been a primary strategy in protective pelvic floor care, the influence of hip acceleration and breathing patterns should be considered with similar importance in future work.

Characterizing Pelvic Floor Muscle Activity During Walking and Jogging in Continent Adults: A Cross-Sectional Study

Introduction

The pelvic floor muscles (PFM) are active during motor tasks that increase intra-abdominal pressure, but little is known about how the PFM respond to dynamic activities, such as gait. The purpose of this study was to characterize and compare PFM activity during walking and jogging in continent adults across the entire gait cycle.

Methods

17 able-bodied individuals (8 females) with no history of incontinence participated in this study. We recorded electromyography (EMG) from the abdominal muscles, gluteus maximus (GM), and PFM while participants performed attempted maximum voluntary contractions (aMVC) of all muscles and completed 60–70 strides in four gait conditions: slow walk (1 km/h); regular walk (self-selected comfortable pace); transition walk (self-selected fastest walking pace); jog (same speed as transition walking). We quantified activity throughout the whole gait cycle (%aMVCGC) and during periods of bursting (%aMVCBR) for each participant, and analyzed the timing of PFM bursting periods to explore when the PFM were most active in the gait cycle. We also conducted a phase metric analysis on the PFM and GM burst timings. We performed a Spearman's rank-order correlation to examine the effect of speed on %aMVCGC, %aMVCBR, and phase metric score, and used the Wilcoxon Signed-Rank test to evaluate the effect of gait modality, matched for speed (walking vs. jogging), on these variables.

Results

The PFM were active throughout the gait cycle, with bursts typically occurring during single-leg support. The PFM and GM were in phase for 44–69% of the gait cycle, depending on condition. There was a positive correlation between gait speed and both %aMVCGC and %aMVCBR (p &lt; 0.001). Phase metric scores were significantly higher during jogging than transition walking (p = 0.005), but there was no difference between gait modality on %aMVCGC or %aMVCBR (p = 0.059). Where possible we disaggregated data by sex, although were unable to make statistical comparisons due to low sample sizes.

Conclusion

The PFM are active during walking and jogging, with greater activity at faster speeds and with bursts in activity around single-leg support. The PFM and GM co-activate during gait, but are not completely in phase with each other.

Influence of toileting behavior on the natural course of anterior vaginal wall prolapse

Background

Many risk factors for pelvic organ prolapse (POP) have been proposed, and the cause is most likely multifactorial. This study aimed to investigate the effect of toileting behaviors on the natural course of anterior vaginal wall prolapse (AVWP).

Methods

Data on 75 women who underwent surgery for symptomatic AVWP were collected. Patients with grade ≥ II AVWP were included in this study and were divided into two groups according to their voiding and defecation position. The volunteers who voided and defecated in a sitting position comprised Group 1, and those who voided and defecated in a squatting position comprised Group 2. The Colorectal-Anal Impact Questionnaire (CRAIQ), Pelvic Floor Impact Questionnaire (PFIQ), Pelvic Organ Prolapse Impact Questionnaire (POPIQ), Urinary Impact Questionnaire (UIQ) and visual analog scale (VAS) pain scores were used to evaluate the patients’ symptoms.

Results

Forty-four patients were included in Group 1 (sitting position), and 31 patients were included in Group 2 (squatting position). The groups were similar in terms of BMI, parity, menopause duration, topical estrogen use, comorbidities, the presence of constipation and urinary incontinence, and the pad count for incontinence. The time from initial symptoms to surgery was shorter in Group 2 than in Group 1 12 (3–73) and 24 (2–182) months (p = 0.001), respectively. The PFIQ, POPIQ and POP-related VAS scores were significantly higher in patients who voided and defecated in a squatting position.

Conclusion

In patients with symptomatic POP, increased IAP while performing the squat position during defecation and voiding may increase the severity of patients' symptoms related to prolapse more than that of sitting position. Therefore, questioning the toileting position of patients with AVWP may help inform management decisions, with changing to a sitting position encouraged.

Relative and Maximal Intra-abdominal Pressure and Postpartum Pelvic Floor Outcomes in Primiparas Delivered Vaginally

OBJECTIVES

This study aimed to explore associations between relative and maximal intra-abdominal pressure (IAP) on pelvic floor outcomes in primiparas delivered vaginally.

METHODS

At 5-10 weeks and 1 year postpartum, we measured absolute IAP by vaginal sensor while participants lifted a weighted car seat (IAPLIFT) and performed isometric trunk flexion endurance (IAPTFE) and seated maximal strain (IAPSTRAIN). Primary outcomes, completed 1 year postpartum, included worse pelvic floor support (descent to or beyond the hymen) and positive symptom burden (bothersome symptoms in ≥2 of 6 domains on the Epidemiology of Prolapse and Incontinence Questionnaire). We calculated relative IAP (as absolute IAP/IAPSTRAIN).

RESULTS

Of 542 participants, 9.7% demonstrated worse support and 54.3% demonstrated symptom burden at 1 year postpartum. In multivariable analyses, absolute IAPLIFT and absolute IAPTFE at 5-10 weeks postpartum were not associated with worse support. As relative IAP at 5-10 weeks increased, the prevalence of worse support decreased (prevalence ratio [PR] of 0.77 [95% confidence intervals (CIs), 0.63-0.94] and PR of 0.79 [95% CI, 0.67-0.93]) per 10% increase for relative IAPLIFT and relative IAPTFE, respectively. This was largely due to IAPSTRAIN, which increased the prevalence of worse support (PR, 1.15 [95% CI, 1.06-1.25]) per 10 cm H2O increase. One year postpartum, only IAPSTRAIN increased the prevalence of worse support (PR, 1.11 [95% CI, 1.02-1.20]) per 10 cm H2O. Of all IAP measures at both time points, only absolute IAPLIFT at 1 year significantly increased the prevalence of symptom burden (PR, 1.11 [95% CI, 1.05-1.18]) per 10 cm H2O.

CONCLUSIONS

This exploratory analysis suggests that postpartum IAPSTRAIN may increase the prevalence of worse support in primiparas delivered vaginally.

Pelvic floor muscle function differs between supine and standing positions in women with stress urinary incontinence: an experimental crossover study

QUESTION

In women with stress urinary incontinence, how does pelvic floor muscle (PFM) function differ between supine and standing when assessed using manometry, vaginal palpation, dynamometry and electromyography?

DESIGN

An experimental crossover study.

PARTICIPANTS

A total of 101 women with stress urinary incontinence were included.

INTERVENTION

The PFM evaluations were performed and compared in supine and standing positions. The participants were assigned to either Group 1 (assessments in supine followed by standing) or Group 2 (assessments in standing followed by supine).

OUTCOME MEASURES

The primary outcome was the PFM pressure during the maximum voluntary contraction (MVC). Secondary outcomes were the measures of PFM pressure at rest; PFM function (PERFECT scheme); active and passive forces (dynamometry); and PFM electromyography (EMG) activity.

RESULTS

The mean MVC pressure was significantly lower in standing (MD -7 cmH₂O, 95% CI -10 to -4). The mean PFM resting pressure was higher in standing (7 cmH₂O, 95% CI 5 to 10). Three measures of PFM function derived from vaginal palpation were better in supine than in standing. The PFM active and the passive forces measured using dynamometry were higher in standing (0.18 kgf, 95% CI 0.16 to 0.20). The resting EMG activity was higher in standing than in supine (MD 3.6 μV, 95% CI 2.6 to 4.5), whereas EMG activity during MVC was higher in supine than standing (MD -8.7 μV, 95% CI -12.5 to -4.8).

CONCLUSION

The pressure and EMG activity during MVC, and PFM function were lower in standing. The resting pressure, the passive and active forces of the PFM and the resting EMG activity of the PFM were higher in standing.

Design, mechanical and degradation requirements of biodegradable metal mesh for pelvic floor reconstruction

Pelvic organ prolapse (POP) is the herniation of surrounding tissue and organs into the vagina and or rectum, and is a result of weakening of pelvic floor muscles, connective tissue,...

Investigation of Murine Vaginal Creep Response to Altered Mechanical Loads

The vagina is a viscoelastic fibromuscular organ that provides support to the pelvic organs. The viscoelastic properties of the vagina are understudied but may be critical for pelvic stability. Most studies evaluate vaginal viscoelasticity under a single uniaxial load; however, the vagina is subjected to dynamic multiaxial loading in the body. It is unknown how varied multiaxial loading conditions affect vaginal viscoelastic behavior and which microstructural processes dictate the viscoelastic response. Therefore, the objective was to develop methods using extension-inflation protocols to quantify vaginal viscoelastic creep under various circumferential and axial loads. Then, the protocol was applied to quantify vaginal creep and collagen microstructure in the fibulin-5 wildtype and haploinsufficient vaginas. To evaluate pressure-dependent creep, the fibulin-5 wildtype and haploinsufficient vaginas (n = 7/genotype) were subjected to various constant pressures at the physiologic length for 100 s. For axial length-dependent creep, the vaginas (n = 7/genotype) were extended to various fixed axial lengths then subjected to the mean in vivo pressure for 100 s. Second-harmonic generation imaging was performed to quantify collagen fiber organization and undulation (n = 3/genotype). Increased pressure significantly increased creep strain in the wildtype, but not the haploinsufficient vagina. The axial length did not significantly affect the creep rate or strain in both genotypes. Collagen undulation varied through the depth of the subepithelium but not between genotypes. These findings suggest that the creep response to loading may vary with biological processes and pathologies, therefore, evaluating vaginal creep under various circumferential loads may be important to understand vaginal function.

IMACTIV: A Pilot Study of the Impact of Unrestricted Activity Following Urethral Sling Surgery

OBJECTIVES

To compare continence outcomes and health-related quality of life (HRQOL) among women with limited activity restrictions vs traditional restrictions following mid-urethral sling (MUS) surgery.

METHODS

Thirty-six women who underwent MUS surgery were randomized: (1) the Restrictions group was given traditional postoperative restrictions for 6 weeks while (2) the Limited Restrictions group was instructed to resume normal activities other than pelvic rest. Patients undergoing concomitant surgery for Stage III and IV prolapse were excluded. Participants completed questionnaires related to urinary symptoms (UDI-6, IIQ-7) for continence outcomes and HRQOL (SF-12) at baseline, 1 to 6 weeks, 3 months, 6 months, and at least 1 year after surgery.

RESULTS

There was no difference in mean scores on the UDI-6 or IIQ-7 between groups at baseline or any time after surgery. The Limited Restrictions group reported better scores than the Restrictions group on the SF-12 mental health component at 1 week (56.7 vs 50.2, P = .01) and 4 weeks (58.4 vs 53.3, P = .04). The Restrictions group reported better SF-12 physical health scores at 5 weeks (55.7 vs 53.0, P = .02) but there was no difference in HRQOL scores between the two groups at any other time.

CONCLUSION

In this pilot study, there was no difference in continence outcomes for women with traditional vs limited activity restrictions following MUS surgery. There were differences in HRQOL in the early post-operative period, but these differences were not sustained. Larger prospective studies are needed, but it appears that activity restrictions after MUS surgery may not be necessary.

Transversus Abdominis and Lumbar Multifidus Thickness Among Three Dance Positions in Argentine Tango Dancers

Core muscle function is considered a risk factor for low back pain appearance in dancers. The purpose of this study was to examine the transversus abdominis and lumbar multifidus thickness among Argentine Tango dancers in different functional dance positions. A secondary purpose was to compare muscle thickness at rest and contraction between dancers and untrained participants. Ten trained dancers and ten untrained women aged 33.8 ± 6.09 years participated in this study. Using ultrasonography, the transversus abdominis and lumbar multifidus muscle thickness were measured at rest and during contraction in three different dance positions: Basic in Open embrace, Basic in Close embrace, and Volcada. The results showed a significant increase in muscle thickness during contraction compared to thickness at rest for both muscles (p < 0.05). The group of dancers showed a greater transversus abdominis thickness than the untrained group (p < 0.05). Further, transversus abdominal thickness progressively increased from Basic in Open embrace to Basic in Close embrace position, as well as from Basic in Close embrace to Volcada position in dancers (p < 0.05), while fewer changes between positions were found for the untrained group. Multifidus muscle thickness also differed between positions, but no group differences were observed (p > 0.05). Training exercises in these Argentine Tango positions may be beneficial for the performance and prevention of low back pain, especially in Argentine Tango dancers.

Do women runners report more pelvic floor symptoms than women in CrossFit®? A cross-sectional survey

INTRODUCTION AND HYPOTHESIS

Women who perform high-impact activities might be at greater risk of pelvic floor dysfunction (PFD) than those participating in low-impact exercise; however, little is known about whether PFD is more common in one type of high-impact activity than another. The aim of this study was to compare the prevalence of PFD symptoms in women who engage in high-impact activity compared with CrossFit®-brand training (CF).

METHODS

An online survey collected data from 1,379 women (521 runners, 858 CF) on exercise participation, parity, and PFD symptoms, via the Pelvic Floor Distress Inventory (PFDI-20). Specific questions from each PFDI-20 subscale further investigated symptoms of pelvic organ prolapse (POP), anal incontinence (AI), as well as stress (SUI) and urgency (UUI) urinary incontinence.

RESULTS

Symptoms of POP and AI were significantly higher in runners (POP 12.7%, AI 34.0%) than in CF (POP 7.8%, p = 0.003; AI 27.7%, p = 0.014). There was no significant difference in SUI symptoms between groups (37.0% vs 41.0% respectively, p = 0.141). Vaginally parous runners reported significantly more symptoms of POP (19.0% vs 12.2%, p = 0.023), AI (39.3% vs 27.2%, p = 0.001), and UUI (36.3% vs 29.0%, p = 0.037) than CF.

CONCLUSION

Women, particularly parous women, who participate in running, have a higher prevalence of POP and AI symptoms than women who participate in CF. This suggests that CrossFit®-brand training might not be more detrimental to PFD symptoms than other high-impact activity, such as running. This study does not conclude a pelvic floor health benefit of one exercise over another, but highlights that exercise options can be provided to women.