Three dimensional model of the female perineum and pelvic floor muscles

Finite element analysis of female pelvic organ prolapse mechanism: current landscape and future opportunities

The prevalence of pelvic organ prolapse (POP) has been steadily increasing over the years, rendering it a pressing global health concern that significantly impacts women's physical and mental wellbeing as well as their overall quality of life. With the advancement of three-dimensional reconstruction and computer simulation techniques for pelvic floor structures, research on POP has progressively shifted toward a biomechanical focus. Finite element (FE) analysis is an established tool to analyze the biomechanics of complex systems. With the advancement of computer technology, an increasing number of researchers are now employing FE analysis to investigate the pathogenesis of POP in women. There is a considerable number of research on the female pelvic FE analysis and to date there has been less review of this technique. In this review article, we summarized the current research status of FE analysis in various types of POP diseases and provided a detailed explanation of the issues and future development in pelvic floor disorders. Currently, the application of FE analysis in POP is still in its exploratory stage and has inherent limitations. Through continuous development and optimization of various technologies, this technique can be employed with greater accuracy to depict the true functional state of the pelvic floor, thereby enhancing the supplementation of the POP mechanism from the perspective of computer biomechanics.

Secondary urethral sphincter function of the rabbit pelvic and perineal muscles

Perineal and pelvic floor muscles play an important role in continence by providing mechanical support to pelvic organs. It is also known that the pubococcygeus muscle (PcM) contracts in the storage phase and is inactive during voiding, while the bulbospongiosus muscle (BsM) is active during the voiding phase. Recent evidence suggested an additional role of these muscles in supporting urethral closure in rabbits. However, the individual role of perineal and pelvic muscles as urethral sphincters is not well-defined. Here we evaluated the individual, sequential and synergistic roles of the PcM and BsM in assisting urethral closure and defined the optimal electrical stimulation parameters that can effectively contract these muscles and increase the urethral pressure (P _ura ) in young nulliparous animals (n = 11). Unilateral stimulation of either the BsM or PcM at 40 Hz induced modest increases in average P _ura (0.23 ± 0.10 and 0.07 ± 0.04 mmHg, respectively). Investigation on the changes in P _ura evoked by stimulation frequencies between 5 and 60 Hz show that sequential contralateral PcM-BsM activation at 40 Hz induced a 2-fold average P _ura increase (0.23 ± 0.07 mmHg) compared to that evoked by PcM stimulation. Simultaneous activation of PcM and BsM at 40 Hz also showed an increased average P _ura (0.26 ± 0.04 mmHg), with a 2-fold increase in average P _ura observed during the unilateral sequential PcM-BsM stimulation at 40 Hz (0.69 ± 0.2 mmHg). Finally, stimulation at 40 Hz of the bulbospongiosus nerve (BsN) induced an approximate 4-fold increase in average P _ura (0.87 ± 0.44 mmHg; p < 0.04) compared to that elicited by BsM stimulation, confirming that direct nerve stimulation is more effective. Together, this study shows that in the female rabbit, both perineal and pelvic muscles support of the urethral function during continence, and that unilateral stimulation of the BsN at 40-60 Hz is sufficient to achieve maximal secondary sphincter activity. The results also support the potential clinical value of neuromodulation of pelvic and perineal nerves as bioelectronic therapy for stress urinary incontinence.

Comparison of the Perineal Body Between Chinese Women With Pelvic Organ Prolapse and Women With Normal Support by Magnetic Resonance Imaging With 3-Dimensional Reconstruction

OBJECTIVE

This study aimed to determine whether the perineal body (PB) is different between women with and without prolapse and to analyze its association with prolapse.

METHODS

This cross-sectional observational study was performed in a tertiary-level urology department and included patients with stage II-IV pelvic organ prolapse (POP) and normal controls with all points 1 cm or more above the hymen. The patients underwent supine midsagittal magnetic resonance imaging (MRI) at rest and during the maximum Valsalva maneuver. Perineal mobility and PB length, height, perimeter, and area were measured; in addition, the genital hiatus and PB were measured according to the definition of the Pelvic Organ Prolapse Quantification system. Univariate associations of POP with characteristics were assessed using the chi-square test or Fisher exact test for categorical variables and the t test for continuous variables. Multivariate logistic regression analysis was used to estimate the adjusted odds ratios and 95% confidence intervals.

RESULTS

Seventy-two controls and 130 patients were analyzed. The PB length, height, and area measurements were significantly lower in the POP group. The perineal mobility in different directions was significantly higher in the POP group. Multivariate analysis demonstrated that the PB area and perineal mobility in the ventral-dorsal and cranio-caudal directions were associated with POP.

CONCLUSIONS

Our data suggest that a smaller PB area and greater dorsal or caudal mobility are associated with prolapse.

45 years' experience with early childhood anatomical technique of feminising genitoplasty for 46 XX Congenital Adrenal Hyperplasia -observations of vaginal introital anatomy and its relationship to the perineal body

In Manchester, feminising genitoplasty is offered to children with 46XX Congenital Adrenal Hyperplasia (CAH) when there is a single perineal opening and/or enlarged clitoris. Our aims are to describe the anatomical reconstructive technique and present long-term outcomes. Our hypothesis is that 'the common channel (CC) length and distance to the vagina from perineal skin is mostly due to virilisation and hypertrophy of perineal tissue over the almost normally positioned vaginal introitus (V-I) in relation to the perineal body (PB)'. METHOD AND RESULTS: This is a retrospective notes review of all consecutive 46XX CAH operations from 1976 to December 2021. 99 patients, who had feminising genitoplasty and being followed-up, were included. 15 patients who were lost to follow up were excluded. Median age at surgery was 15 months. In 91, midline division of the labia majora, spongiosum, bulbo-spongiosus muscle (BSM) and CC down to PB was performed. This was sufficient to expose the V-I at the same level or within 5 mm depth of PB in 88. In 78 V-I was adequate taking 10/12fr dilator (Type 1). In 10, CC resembled a male urethra and V-I was narrow (Type 2), requiring widening by 5-10 mm incision at 6 o'clock position. Dartos of labia majora was attached to BSM to reduce the distance to V-I from perineal skin and the gap was lined with inner foreskin to create a vestibule. Out of 70 who were post-pubertal, 75% (53/70) had adequate calibre vaginal openings. 5 had introitoplasty and 2 had dilatation under anaesthesia. 10 needed self dilators only. 29 patients, of one of the three surgeons, had measurements of clitoris, CC, urethra and vagina. A hymen was found in 86% (25/29). There was significant strong, inverse correlation between the CC length and the urethral length (r = -0.708, p < 0.001, n = 27) but not between CC and vaginal lengths. After adjusting for age, the urethral length of Type 2 patients was 3.825 mm shorter than those of Type 1 (p = 0.017). CONCLUSION: Our data show that 'high' confluence is mostly due to virilisation of genitalia; and the anatomical technique of reversing the fusion of the urethral folds, spongiosum and bulbo-spongiosus muscle could be performed with all degrees of virilisation with success in early childhood with no need of local flaps or mobilisation of the urethro-vaginal complex. About 10% require surgery to treat narrowing of vaginal opening post puberty.

Study on circumpelvic muscle deformation and dynamic simulation of pelvic fracture reduction

For the pelvic fracture reduction, generally the fragment of the unaffected side is fixed and the affected side is moved to its correct anatomical position and orientation. During the pelvic fracture reduction, circumpelvic muscles deformation is closely related to the surgical accuracy. In this article, the biomechanical properties of musculoskeletal tissue during pelvic fracture reduction are studied. Five-parameter hyperelastic model named Mooney-Rivlin is adopted to analyze muscle's stress-strain relationship. The finite element model of the injured pelvic musculoskeletal tissue is established, and the deformation of circumpelvic main muscles is simulated. Then, the dynamic simulation of pelvic fracture reduction is performed according to the planned spatial reduction path. The results show that when the muscles are stretched the same stretch length, the strain of the gluteus medius is the largest. It is most prone to deformation under and the muscle injury is most easily to occur. During the pelvic fracture reduction, the strain of gluteus maximus is the largest, and it is most prone to deformation and injury. The traction length is the largest, and the traction force mainly comes from the gluteus maximus. This study provides reference for the robot assisted pelvic fracture reduction.

Simulation of the mobility of the pelvic system: influence of fascia between organs

The mobility of pelvic organs is the result of an equilibrium called Pelvic Static characterizing the balance between the properties and geometries of organs, suspensions and support system. Any imbalance in this complex system can cause of pelvic static disorder. Genital prolapse is a common hypermobility pathology which is complex, multi factorial and its surgical management has high rate of complications. The use of 3 D numerical models and simulation enables the role of the various suspension structures to be objectively studied and quantified. Fascias are connective tissues located between organs. Although their role are described as important in various descriptions of pelvic statics, their influence and role has never been quantitatively objectified. This article presents a refine Finite Element (FE) model for a better understanding of biomechanical contribution of inter-organ fascia. The model is built from MRI images of a young volunteer, the mechanical properties derived from literature data to take into account the age of the patient and new experimental results have enabled an order of magnitude of the mechanical properties of the fascias to be defined. The FE results allows to quantify the biomechanical role of the fascia on pelvic mobility quantified by an analysis of dynamic MRI images and a local mapping of the gap between calculated and measured displacements. This improved numerical model integrating the fascias makes it possible to describe pelvic mobilities with a gap of 1 mm between numerical simulations and measurements, whereas without taking them into account this gap locally reaches 20 mm.

Childbirth Computational Models: Characteristics and Applications

The biomechanical process of childbirth is necessary to usher in new lives-but it can also result in trauma. This physically intense process can put both the mother and the child at risk of injuries and complications that have life-long impact. Computational models, as a powerful tool to simulate and explore complex phenomena, have been used to improve our understanding of childbirth processes and related injuries since the 1990s. The goal of this paper is to review and summarize the breadth and current state of the computational models of childbirth in the literature-focusing on those that investigate the mechanical process and effects. We first summarize the state of critical characteristics that have been included in computational models of childbirth (i.e., maternal anatomy, fetal anatomy, cardinal movements, and maternal soft tissue mechanical behavior). We then delve into the findings of the past studies of birth processes and mechanical injuries in an effort to bridge the gap between the theoretical, numerical assessment and the empirical, clinical observations and practices. These findings are from applications of childbirth computational models in four areas: (1) the process of childbirth itself, (2) maternal injuries, (3) fetal injuries, and (4) protective measures employed by clinicians during delivery. Finally, we identify some of the challenges that computational models still face and suggest future directions through which more biofidelic simulations of childbirth might be achieved, with the goal that advancing models may provide more efficient and accurate, patient-specific assessment to support future clinical decision-making.

The Rolf Method of Structural Integration and Pelvic Floor Muscle Facilitation: Preliminary Results of a Randomized, Interventional Study

The management of pelvic floor dysfunctions might need to be based on a comprehensive neuro-musculoskeletal therapy such as The Rolf Method of Structural Integration (SI). The aim of the study was to evaluate the pelvic floor muscle (PFM) after the tenth session of SI by using surface electromyography (sEMG). This was a randomized, interventional study. Thirty-three healthy women were randomly assigned to the experimental (SI) or control group. The outcome measures included PFM bioelectrical activity, assessed using sEMG and endovaginal probes. An intervention in the SI group included 60 min of SI once a week, and teaching on how to contract and relax PFMs; in the control group, only the teaching was carried out. In the SI group, a significant difference was found between the PFM sEMG activity during “pre-baseline rest” (p < 0.014) and that during “rest after tonic contraction” (p = 0.021) in the supine position, as were significant increases in “phasic contraction” in the standing position (p = 0.014). In the intergroup comparison, higher PFM sEMG activity after the intervention “phasic contraction” (p = 0.037) and “pre-baseline rest” (p = 0.028) was observed in the SI group. The SI intervention significantly changes some functional bioelectrical activity of PFMs, providing a basis for further research on a new approach to PFM facilitation, particularly in clinical populations.

Pelvic floor physical therapy in the treatment of pelvic floor dysfunction in women

PURPOSE OF REVIEW

To describe the principles of pelvic floor physical therapy (PFPT), review the evidence for PFPT as a treatment for pelvic floor dysfunction, and summarize the current recommendations for PFPT as a first-line conservative treatment option for pelvic floor disorders.

RECENT FINDINGS

Pelvic floor dysfunction can cause voiding and defecation problems, pelvic organ prolapse (POP), sexual dysfunction, and pelvic pain. PFPT is a program of functional retraining to improve pelvic floor muscle strength, endurance, power, and relaxation in patients with pelvic floor dysfunction. Based on the available evidence, PFPT with or without supplemental modalities can improve or cure symptoms of urinary incontinence, POP, fecal incontinence, peripartum and postpartum pelvic floor dysfunction, and hypertonic pelvic floor disorders, including pelvic floor myofascial pain, dyspareunia, vaginismus, and vulvodynia. Currently, there is conflicting evidence regarding the effectiveness of perioperative PFPT before or after POP and urinary incontinence surgery.

SUMMARY

PFPT has robust evidence-based support and clear benefit as a first-line treatment for most pelvic floor disorders. Standards of PFPT treatment protocols, however, vary widely and larger well designed trials are recommended to show long-term effectiveness.

In Vivo Imaging-Based 3-Dimensional Pelvic Prototype Models to Improve Education Regarding Sexual Anatomy and Physiology

BACKGROUND

Myths, misconceptions, and taboos about sexual anatomy and physiology are common and can affect sexual health and maintain harmful practices and beliefs.

AIM

To construct a female and a preliminary male 3-dimensional (3D) pelvic model on the basis of in vivo imaging, which could be studied in sex education and clinical practice.

METHODS

We retrospectively studied the images of 200 female pelvic magnetic resonance examinations and reviewed the literature to choose the optimum magnetic resonance imaging (MRI) protocol for the study of the clitoris and surrounding organs. We also conducted a cross-sectional study of 30 women who were undergoing a pelvic MRI. 15 women had undergone female genital mutilation/cutting involving the clitoris and 15 had not. The best-quality MRI images of 3 uncut and 1 cut clitoris, together with the principal surrounding pelvic organs, were selected to generate 3D reconstructions using dedicated software. The same software was used to reconstruct the anatomy of the penis and the principal surrounding pelvic organs, based on contrast-enhanced computer tomography images. Images of both models were exported in .stl format and cleaned to obtain single manifold objects in free, open source software. Each organ model was sliced and 3D printed. A preliminary feedback was collected from 13 potential users working in urology, gynaecology, sexual medicine, physiotherapy, and education.

OUTCOMES

The main outcomes of this study are a kit of 3D pelvic models, 2-dimensional figures of female and male sexual anatomy, and files for 3D printing.

RESULTS

We present a kit containing 3D models and 2-dimensional figures of female and male sexual anatomy, based on in vivo imaging and, feedbacks and suggestions received from potential users.

CLINICAL TRANSLATION

Our kit can be used in anatomy and sex education among and by health professionals, teachers, sex educators, students, and the general population.

STRENGTHS & LIMITATIONS

The strengths are that the models were based on in vivo imaging, can be dismantled/reassembled, and show analogous anatomic structures of the clitoris and the penis. The female models represent diversity, including women with female genital mutilation/cutting. The limitations are that the male model is preliminary and can be improved if based on an MRI; that imaging-based anatomic representations can differ from anatomic dissections; and that the models represent the sexual organs at rest or during an unknown state of arousal only.

CONCLUSION

Our kit can be studied in anatomy, biology, and sex education, as well as in clinical practice. Abdulcadir J, Dewaele R, Firmenich N, et al. In Vivo Imaging-Based 3-Dimensional Pelvic Prototype Models to Improve Education Regarding Sexual Anatomy and Physiology. J Sex Med 2020;17:1590-1602.

Development of a standardized, reproducible screening examination for assessment of pelvic floor myofascial pain

BACKGROUND

Pelvic floor myofascial pain is common, but physical examination methods to assess pelvic floor muscles are defined poorly. We hypothesized that a simple, transvaginal pelvic floor examination could be developed that would be highly reproducible among providers and would adequately screen for the presence of pelvic floor myofascial pain.

OBJECTIVE

The purpose of this study was to develop a simple, reproducible pelvic floor examination to screen for pelvic floor myofascial pain.

STUDY DESIGN

A screening examination was developed by Female Pelvic Medicine & Reconstructive Surgery subspecialists and women's health physical therapists at our institution and tested in a simulated patient. We recruited 35 new patients who underwent examinations by blinded, paired, independent examiners. Agreement was calculated with the use of percent agreement and Spearman's rank correlation coefficient.

RESULTS

The final examination protocol begins with examination of the following external sites: bilateral sacroiliac joints, medial edge of the anterior superior iliac spine, and cephalad edge of the pubic symphysis (self-reported pain: yes/no). The internal examination follows with palpation of each muscle group in the center of the muscle belly, then along the length of the muscle proceeding counter-clockwise: right obturator internus, right levator ani, left levator ani, left obturator internus (pain on a scale of 0-10). Thirty-five patients were enrolled. Correlation was high at each external (0.80-0.89) and internal point (0.63-0.87; P<.0001).

CONCLUSION

Our newly developed, standardized, reproducible examination incorporates assessment of internal and external points to screen for pelvic floor myofascial pain. The examination is straightforward and reproducible and allows for easy use in clinical practice.

Factors associated with pelvic floor disorders in Kersa District, eastern Ethiopia: a community-based study

BACKGROUND

Pelvic floor disorders, which diminish the quality of life, disproportionally affect women in developing countries. However, there is a knowledge gap in the understanding of the factors associated with the problem in many countries including Ethiopia. Therefore, we aimed to assess the factors associated with pelvic floor disorders in Ethiopia.

MATERIALS AND METHODS

A community-based cross-sectional study was conducted among 3432 ever-married women selected through a stratified multistage sampling procedure from the Kersa Health and Demography Surveillance System. Data were collected using structured questionnaires through face-to-face interviews. A Poisson regression model with robust variance estimation was used to investigate the association of the independent variable with pelvic floor disorder. The results are reported in adjusted prevalence ratios with 95% confidence intervals.

RESULTS

Overall, the prevalence of pelvic floor disorders was 20.5% (95% CI: 19%-22%). Women who had no education (APR = 1.47; 95% CI: 1.06, 2.04) or had undergone five or more vaginal deliveries (APR = 1.56; 95% CI: 1.18, 2.05), an abortion (APR = 1.85; 95% CI: 1.43, 2.38) or episiotomy (APR = 1.39; 95% CI: 1.02, 1.90) were independently associated with having pelvic floor disorders.

CONCLUSION

Obstetric events are strongly associated with pelvic floor disorders. This finding highlights the greater need for policies to focus on prevention, diagnosis and treatment services to mitigate women's suffering from pelvic floor disorders.