A review of functional pelvic floor imaging modalities and their effectiveness

Quantifying the effect of an endo-vaginal probe on position of the pelvic floor viscera and muscles

INTRODUCTION AND HYPOTHESIS

Endovaginal ultrasound has long been hypothesized to have a significant effect on locations of what it visualizes. However, little work has directly quantified its effect. This study aimed to quantify it.

METHODS

This cross-sectional study consisted of 20 healthy asymptomatic volunteers who underwent both endovaginal ultrasound and MRI. The urethra, vagina, rectum, pelvic floor, and pubic bone were segmented in both ultrasound and MRI using 3DSlicer. Then, using 3DSlicer's transform tool the volumes were rigidly aligned based on the posterior curvature of the pubic bone. The organs were then split into thirds along their long axis to compare their distal, middle, and proximal sections. Using Houdini, we compared the location of the centroid of each of the urethra, vagina, and rectum and the surface-to-surface difference of the urethra and rectum. The anterior curvature of the pelvic floor was also compared. Normality of all variables was assessed by Shapiro-Wilk test.

RESULTS

The largest amount of surface-to-surface distance was observed in the proximal region for the urethra and rectum. Across all three organs, the majority of the deviation was in the anterior direction for geometries obtained from ultrasound versus those from MRI. For each subject, the trace defining the midline of the levator plate was more anterior for ultrasound compared to MRI.

CONCLUSIONS

While it has often been assumed that placing a probe in the vagina probably distorts the anatomy, this study quantified the distortion and displacement of the pelvic viscera. This allows for better interpretation of clinical and research findings based on this modality.

Biomechanical integrity score of the female pelvic floor

INTRODUCTION AND HYPOTHESIS

The aim of this study is to develop and validate a new integral parameter, the Biomechanical Integrity score (BI-score), for the characterization of the female pelvic floor.

METHODS

A total of 253 subjects with normal and pelvic organ prolapse (POP) conditions were included in the multi-site observational, case-control study; 125 subjects had normal pelvic floor conditions, and 128 subjects had POP stage II or higher. A Vaginal Tactile Imager (VTI) was used to acquire and automatically calculate 52 biomechanical parameters for eight VTI test procedures (probe insertion, elevation, rotation, Valsalva maneuver, voluntary muscle contractions in two planes, relaxation, and reflex contraction). Statistical methods were applied (t-test, correlation) to identify the VTI parameters sensitive to the pelvic conditions.

RESULTS

Twenty-six parameters were identified as statistically sensitive to POP development. They were subdivided into five groups to characterize (1) tissue elasticity, (2) pelvic support, (3) pelvic muscle contraction, (4) involuntary muscle relaxation, and (5) pelvic muscle mobility. Every parameter was transformed to its standard deviation units against the patient age similar to T-score for bone density. Linear combinations with specified weights led to the composition of five component parameters for groups (1)-(5) and the BI-score in standard deviation units. The p-value for the BI-score has p = 4.3 × 10^-31 for POP versus normal conditions. A reference BI-score curve against age for normal pelvic floor conditions was defined.

CONCLUSIONS

Quantitative transformations of the pelvic tissues, support structures, and functions under diseased conditions may be studied with the BI-score in future research and practical applications.

Bladder Base Displacement during Abdominal Muscles Contraction and Functional Activities in Primiparous Women Assessed by Transabdominal Ultrasound: A Descriptive Study

This study described the response of the bladder base (BB) by transabdominal ultrasound in primiparous women during movements that activate the abdominopelvic cavity musculature and cause variations in intra-abdominal pressure (IAP). A descriptive cross-sectional study was conducted in 64 primiparous women at eight weeks after uncomplicated delivery. BB displacement was measured using a 5-MHz convex transducer in a suprapubic position. Participants were asked to perform the isolated contraction of pelvic floor musculature (PFM) and transverse abdominis (TrA), cough at high lung volume and trunk flexion with and without maximal voluntary contraction of PFM. PFM contraction elevated the BB in all but one participant, whereas TrA contraction caused the BB to ascend in 56% of the women and descend in the rest; their combined contraction rose the BB in 65% of the women although the effect was greater with only PFM contraction (p < 0.01). The BB descended in all participants during coughing and trunk flexion although the descent was inferior with the joint maximal voluntary contraction of PFM (p < 0.01). In conclusion, TrA contraction must be assessed individually in puerperal women since its effect on the BB varies among subjects. During movements increasing IAP, such as coughing or curl-ups, the anticipatory contraction of PFM reduces bladder descent although not sufficiently to counteract bladder displacement.

The use of dynamic MR imaging in patients with clinical pelvic floor disorders

OBJECTIVES

To determine the differences and challenging aspects of dynamic magnetic resonance defecography (MRD) compared to conventional defecography (CD) in diagnostic of clinical symptomatic pelvic floor dysfunction.

METHODS

Fifty patients (44 females, 6 males; mean age: 57 years) with symptomatic pelvic floor dysfunction underwent both examinations, CD and MRD. Results were retrospectively intra-individual and interindividual evaluated in this multicentre study. Visibility and accuracy in diagnosis and classification of rectal prolapse, rectocele, enterocele, sigma diverticula and Cul-de-sac phenomenon/syndrome were observed. Differences were analysed using Mann-Whitney U test. P-values < 0.05 were considered as statistically significant.

RESULTS

CD was significantly superior to MRD in diagnosis and grading of rectal prolapse (p < .001), diagnosis and metric measurements of rectoceles (p = .016), diagnosis of elongated sigmoid colon (p = .008) and Cul-de-sac phenomenon and syndrome, respectively (p = .015; p = .008). MRD revealed equal results to CD in detection, localization, tendency to retention and enlargement of rectoceles (p = .337) and findings of enteroceles (p = .604) as well as sigma diverticula (p = .149).

CONCLUSIONS

The complementary use of both examination methods, CD and MRD, is important to achieve a comprehensive look on every aspect of pelvic floor disorders and gain optimal results in detection and evaluation of all major disorders of the pelvic floor.

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

PURPOSE OF REVIEW

Weakened pelvic floor support is believed to be the main cause of various pelvic floor disorders. Modern theories of pelvic floor support stress on the structural and functional integrity of multiple structures and their interplay to maintain normal pelvic floor functions. Connective tissues provide passive pelvic floor support while pelvic floor muscles provide active support through voluntary contraction. Advanced modern medical technologies allow us to comprehensively and thoroughly evaluate the interaction of supporting structures and assess both active and passive support functions. The pathophysiology of various pelvic floor disorders associated with pelvic floor weakness is now under scrutiny from the combination of (1) morphological, (2) dynamic (through computational modeling), and (3) neurophysiological perspectives. This topical review aims to update newly emerged studies assessing pelvic floor support function among these three categories.

RECENT FINDINGS

A literature search was performed with emphasis on (1) medical imaging studies that assess pelvic floor muscle architecture, (2) subject-specific computational modeling studies that address new topics such as modeling muscle contractions, and (3) pelvic floor neurophysiology studies that report novel devices or findings such as high-density surface electromyography techniques. We found that recent computational modeling studies are featured with more realistic soft tissue constitutive models (e.g., active muscle contraction) as well as an increasing interest in simulating surgical interventions (e.g., artificial sphincter). Diffusion tensor imaging provides a useful non-invasive tool to characterize pelvic floor muscles at the microstructural level, which can be potentially used to improve the accuracy of the simulation of muscle contraction. Studies using high-density surface electromyography anal and vaginal probes on large patient cohorts have been recently reported. Influences of vaginal delivery on the distribution of innervation zones of pelvic floor muscles are clarified, providing useful guidance for a better protection of women during delivery. We are now in a period of transition to advanced diagnostic and predictive pelvic floor medicine. Our findings highlight the application of diffusion tensor imaging, computational models with consideration of active pelvic floor muscle contraction, high-density surface electromyography, and their potential integration, as tools to push the boundary of our knowledge in pelvic floor support and better shape current clinical practice.

Temporary successful results of ventral rectopexy for enterocele surgical correction, about 138 patients

PURPOSE

This work aimed to analyse short- and long-term results of enterocele surgical treatment by ventral rectopexy.

METHODS

All females who underwent ventral rectopexy for enterocele in our department were included. All patients underwent standardized preoperative evaluation. Data was retrospectively collected, after examination of patients or by telephone survey. Postoperative evaluation was performed by an independent observer.

RESULTS

One hundred thirty-eight females (median age = 63 years [21-86 years]) were included. They were postmenopausal and multiparous in 94 and 70% of cases, respectively. Pelvic pressure, vaginal prolapse, or the both were observed in 28, 16 or 56% of the patients, respectively. The most frequent associated symptoms were dyschezia (63%) and faecal incontinence (30%). On preoperative workup, enterocele was isolated in two cases. Rectocele, internal rectal prolapse and cervicocystoptosis were the most frequently associated pelvic floor disorders. Ventral rectopexy was performed through laparoscopy in 128 patients (93%). In the short term, all pelvic symptoms were significantly improved, except urinary incontinence. At the end of follow-up (56 months [7-125]), specific symptoms and dyschezia were still significantly improved. Secondary failure was reported in 31% of patients. By multivariate analysis, two predictive factors for long-term failure were found: diagnosis of rectocele on preoperative MRI (odd ratio = 15; 95% CI 1.4-163; p = 0.03) and conversion into open surgery (odd ratio = 8; 95% CI 1.4-43; p = 0.02).

CONCLUSION

This study suggests that ventral rectopexy is an effective treatment of enterocele, but secondary failure can be observed. Patients should be informed of the potential risk of long-term degradation.

Review article: dyssynergic defaecation and biofeedback therapy in the pathophysiology and management of functional constipation

BACKGROUND

Functional constipation is a common clinical presentation in primary care. Functional defaecation disorders are defined as the paradoxical contraction or inadequate relaxation of the pelvic floor muscles during attempted defaecation (dyssynergic defaecation) and/or inadequate propulsive forces during attempted defaecation. Prompt diagnosis and management of dyssynergic defaecation is hindered by uncertainty regarding nomenclature, diagnostic criteria, pathophysiology and efficacy of management options such as biofeedback therapy.

AIM

To review the evidence pertaining to the pathophysiology of functional defaecation disorders and the efficacy of biofeedback therapy in the management of patients with dyssynergic defaecation and functional constipation.

METHODS

Relevant articles addressing functional defaecation disorders and the efficacy of biofeedback therapy in the management of dyssynergic defaecation and functional constipation were identified from a search of Pubmed, MEDLINE Ovid and the Cochrane Library.

RESULTS

The prevalence of dyssynergic defaecation in patients investigated for chronic constipation is as many as 40%. Randomised controlled trials have demonstrated major symptom improvement in 70%-80% of patients undergoing biofeedback therapy for chronic constipation resistant to standard medical therapy and have determined it to be superior to polyethylene glycol laxatives, diazepam or sham therapy. Long-term studies have shown 55%-82% of patients maintain symptom improvement.

CONCLUSIONS

Dyssynergic defaecation is a common clinical condition in patients with chronic constipation not responding to conservative management. Biofeedback therapy appears to be a safe, successful treatment with sustained results for patients with dyssynergic defaecation. Further studies are required to standardise the diagnosis of dyssynergic defaecation in addition to employing systematic protocols for biofeedback therapy.

Paradoxical puborectalis syndrome on diffusion-weighted imaging: a retrospective study of 72 cases

This study aimed to evaluate the application value of diffusion-weighted imaging (DWI) for assessing paradoxical puborectalis syndrome (PPS) in patients with obstructive defecation syndrome (ODS). The medical records of 72 ODS patients who underwent magnetic resonance (MR)-DWI and MR-defecography were retrospectively reviewed. The differences in the apparent diffusion coefficients (ADCs) and the thickness of the right and left branches of the puborectalis muscles between the PPS(+) and PPS(−) groups were compared. In addition, the absolute within-patient differences between the right and left branches (ADC, thickness) were compared between the two groups. The absolute difference in ADCs (right branch - left branch) was significantly different between the two groups. Regardless of whether the ADC was acquired through single-ROI (0.10 ± 0.08 vs 0.23 ± 0.18, P = 0.000) or multi-ROI (0.16 ± 0.14 vs 0.27 ± 0.17, P = 0.009) analysis, the PPS(+) patients displayed a lower absolute ADC difference than did the PPS(−) patients. However, there was no statistically significant difference in the ADC value, thickness or the absolute difference in thickness between the two groups. These findings suggest that DWI may have value in quantitatively assessing the puborectalis muscle in ODS patients, whereas the value of puborectalis thickness in such aspect needs further study.

Functional Disorders of Constipation: Paradoxical Puborectalis Contraction and Increased Perineal Descent

Paradoxical puborectalis contraction (PPC) and increased perineal descent (IPD) are subclasses of obstructive defecation. Often these conditions coexist, which can make the evaluation, workup, and treatment difficult. After a thorough history and examination, workup begins with utilization of proven diagnostic modalities such as cinedefecography and anal manometry. Advancements in technology have increased the surgeon's diagnostic armamentarium. Biofeedback and pelvic floor therapy have proven efficacy for both conditions as first-line treatment. In circumstances where PPC is refractory to biofeedback therapy, botulinum toxin injection is recommended. Historically, pelvic floor repair has been met with suboptimal results. In IPD, surgical therapy now is directed toward the potentially attendant abnormalities such as rectoanal intussusception and rectal prolapse. When these associated abnormalities are not present, an ostomy should be considered in patients with IPD as well as medically refractory PPC.

Evaluation, Diagnosis, and Medical Management of Rectal Prolapse

Full-thickness rectal prolapse, or procidentia, is the passage of the full-thickness wall of the rectum beyond the anal sphincters. This condition results in pain and fecal incontinence which greatly impairs the quality of life of those afflicted. It is associated with several anatomic abnormalities, including decreased anal sphincter tone, levator muscle diastasis, and a deep anterior cul-de-sac. The diagnosis of rectal prolapse is made based on physical examination, although several other modalities are used to provide additional information about the patients' condition. While medical management of rectal prolapse can be effective in some cases, the mainstay of management of rectal prolapse is surgical correction.

Constipation in parkinson's disease: Subjective symptoms, objective markers, and new perspectives

Constipation is among the first nonmotor symptoms to develop in the prodromal phase of PD. Pathological alpha-synuclein deposition is present throughout the gastrointestinal tract up to 20 years preceding diagnosis. Nevertheless, constipation in the context of PD remains ill defined and poorly understood. In this review, we summarize current knowledge of subjective symptoms and objective measures of constipation in PD. More than 10 different definitions of constipation have been used in the PD literature, making generalizations difficult. When pooling results from the most homogeneous studies in PD, a median constipation prevalence of 40% to 50% emerges, but with large variation across individual studies. Also, constipation prevalence tends to increase with disease progression. A similar prevalence is observed among patients with idiopathic rapid eye movement sleep behavior disorder. Interestingly, we detected a correlation between constipation prevalence in PD patients and healthy control groups in individual studies, raising concerns about how various constipation questionnaires are implemented across study populations. More than 80% of PD patients exhibit prolonged colonic transit time, and the same is probably true for de novo PD patients. Thus, the prevalence of objective colonic dysfunction exceeds the prevalence of subjective constipation. Colonic transit time measures are simple, widely available, and hold promise as a useful biomarker in manifest PD. More research is needed to elucidate the role of gastrointestinal dysfunction in disease progression of PD. Moreover, colonic transit measures may have utility as a more accurate risk factor for predicting PD in the prodromal phase. © 2016 International Parkinson and Movement Disorder Society.

The use of imaging techniques in understanding lower urinary tract (dys)function

The ability to store urine in the bladder and to void at an appropriate time depends on several complex mechanisms in the lower urinary tract (LUT) and its neural control. Normal LUT function requires coordination of the urinary bladder, urethra, pelvic floor, efferent and afferent neurons and specific spinal cord and brain areas. These structures can be visualised using different imaging modalities, such as ultrasound, X-ray and magnetic resonance imaging. The supraspinal neural control of the LUT can be studied using functional brain imaging. During the last two decades, the many technological improvements of these imaging techniques have increased our knowledge of voiding dysfunction. Here, we review the different imaging modalities of the LUT and its neural control and discuss their importance for diagnosing and understanding voiding dysfunction.