Continence and micturition: an anatomical basis

An Overview of the Effect of Aging on the Female Urethra

Urethral function declines by roughly 15% per decade and profoundly contributes to the pathogenesis of urinary incontinence. Individuals with poor urethral function are more likely to fail surgical management for stress incontinence that focus on improving urethral support. The reduced number of intramuscular nerves and the morphologic changes in muscle and connective tissue collectively impact urethral function as women age. Imaging technologies like MRI and ultrasound have advanced our understanding of these changes. However, substantial knowledge gaps remain. Addressing these gaps can be crucial for developing better prevention and treatment strategies, ultimately enhancing the quality of life for aging women.

Partial urogenital mobilization in cloacal malformation: is it a viable option?

INTRODUCTION

Total Urogenital Mobilization (TUM) has been the standard surgical approach for the urogenital complex in Cloacal Malformations (CM) since its inception in 1997. Partial Urogenital Mobilization (PUM) in CM remains an under-utilized or under-reported option. The main anatomical difference between TUM and PUM is the division of the pubo-urethral ligaments.

OBJECTIVE

We explored the feasibility of PUM in a select subset of our patients with CM and report early outcomes.

STUDY DESIGN

We retrospectively reviewed prospectively collected data of all our CM patients who had primary reconstruction at our centre from 2012 to 2020. We included in our review the patients who underwent PUM. Mullerian abnormalities, spinal cord involvement, common channel length (CC), urethral length (UL), surgical reconstruction, and outcomes including urinary continence, recurrent UTI, ultrasound and preoperative DMSA/MAG3, cystovaginoscopy post-reconstruction, and post-void residuals were noted.

RESULTS

Fifty-three patients had primary reconstruction, and of these, eleven had a common channel less than 3 cm. Of the eleven, only one underwent TUM. In the PUM group, two underwent filum untethering (20%). Mullerian duplication was noted in 5 patients (50%). The median CC length = 1.6 cm (range = 1.5cm-2.7 cm), and median UL = 1.5 cm (range = 1.5cm-2.5 cm). Follow-up ranged from 9 to 134months (median = 63months). Post-reconstruction all had a separate urethral and vaginal opening on examination and cysto-vaginoscopy. The continence outcomes are summarized in Fig.1.

DISCUSSION

Although TUM is the most common solution for the urogenital complex in CM, a subset would be suitable for PUM, and this option is under-utilized or under-reported in literature. We presume that many who had TUM probably only needed a PUM, and therefore could report better outcomes from a bladder function aspect. It is important to differentiate the two, and outcomes should be appropriately categorized. Our default approach is a PUM in all CM with less than 3 cm common channel. Only the lateral and posterior aspects of the urogenital complex are mobilized and if the urethra did not reach a satisfactory level for easy intermittent catheterization, then we proceed to a TUM dividing the pubo-urethral ligaments. PUM avoids the potential complications related to dividing the pubo-urethral ligament in TUM. It may also avoid the need for CIC which is encountered in patients who undergo TUM.

CONCLUSION

PUM is a viable alternative in cloacal malformations with good outcomes in those with a common channel under 3 cm. This of course requires appropriate patient selection and accurate categorization of interventions to understand the true outcomes.

The Anatomical Pathogenesis of Stress Urinary Incontinence in Women

Stress urinary incontinence is a common disease in middle-aged and elderly women, which seriously affects the physical and mental health of the patients. For this reason, researchers have carried out a large number of studies on stress urinary incontinence. At present, it is believed that the pathogenesis of the disease is mainly due to changes related to age, childbirth, obesity, constipation and other risk factors that induce changes in the urinary control anatomy, including the anatomical factors of the urethra itself, the anatomical factors around the urethra and the anatomical factors of the pelvic nerve. The combined actions of a variety of factors lead to the occurrence of stress urinary incontinence. This review aims to summarize the anatomical pathogenesis of stress urinary incontinence from the above three perspectives.

Can the inability to contract the pelvic floor muscles influence the severity of urinary incontinence symptoms in females?

INTRODUCTION AND HYPOTHESIS

The objective was to analyze if the inability to perform a maximal voluntary contraction (MVC) of the pelvic floor muscles (PFMs) in a first assessment can influence the severity of urinary incontinence symptoms in women.

METHODS

A cross-sectional study was carried out using the medical records of women with UI who were referred for pelvic floor physiotherapy after undergoing a gynecological evaluation between May 2013 and December 2019. Records included data referring to age, body mass index (BMI), obstetric history, Modified Oxford Scale (MOS), and the final score of the International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF) from a baseline assessment. Data were divided into women who were unable and those who were able to voluntarily perform an MVC of the PFMs. Statistical analysis was conducted using SPSS version 21.

RESULTS

A total of 498 medical records were analyzed and 36.3% of those women were not able to perform a PFM MVC after verbal command and digital stimulus. Homogeneity was observed among groups and no significant difference was found regarding the severity of UI symptoms when the groups were compared.

CONCLUSIONS

No association was found between the inability to contract the PFMs and the severity of UI symptoms. Other studies should be developed to better understand why some women are incapable of performing a voluntary PFM contraction. Also, it would be relevant to compare women with PFM dysfunction who are not able to contract the PFMs with healthy women with the same PFM condition to analyze whether this muscle condition could be related to dysfunctions such as UI or pelvic organ prolapse.

Review: Pelvic nerves - from anatomy and physiology to clinical applications

A prerequisite for nerve-sparing pelvic surgery is a thorough understanding of the topographic anatomy of the fine and intricate pelvic nerve networks, and their connections to the central nervous system. Insights into the functions of pelvic nerves will help to interpret disease symptoms correctly and improve treatment. In this article, we review the anatomy and physiology of autonomic pelvic nerves, including their topography and putative functions. The aim is to achieve a better understanding of the mechanisms of pelvic pain and functional disorders, as well as improve their diagnosis and treatment. The information will also serve as a basis for counseling patients with chronic illnesses. A profound understanding of pelvic neuroanatomy will permit complex surgery in the pelvis without relevant nerve injury.

Increased Dose to Organs in Urinary Tract Associates With Measures of Genitourinary Toxicity in Pooled Voxel-Based Analysis of 3 Randomized Phase III Trials

Purpose: Dose information from organ sub-regions has been shown to be more predictive of genitourinary toxicity than whole organ dose volume histogram information. This study aimed to identify anatomically-localized regions where 3D dose is associated with genitourinary toxicities in healthy tissues throughout the pelvic anatomy. Methods and Materials: Dose distributions for up to 656 patients of the Trans-Tasman Radiation Oncology Group 03.04 RADAR trial were deformably registered onto a single exemplar CT dataset. Voxel- based multiple comparison permutation dose difference testing, Cox regression modeling and LASSO feature selection were used to identify regions where 3D dose-increase was associated with late grade ≥ 2 genitourinary dysuria, incontinence and frequency, and late grade ≥ 1 haematuria. This was externally validated by registering dose distributions from the RT01 (up to n = 388) and CHHiP (up to n = 247) trials onto the same exemplar and repeating the voxel-based tests on each of these data sets. All three datasets were then combined, and the tests repeated. Results: Voxel-based Cox regression and multiple comparison permutation dose difference testing revealed regions where increased dose was correlated with genitourinary toxicity. Increased dose in the vicinity of the membranous and spongy urethra was associated with dysuria for all datasets. Haematuria was similarly correlated with increased dose at the membranous and spongy urethra, for the RADAR, CHHiP, and combined datasets. Some evidence was found for the association between incontinence and increased dose at the internal and external urethral sphincter for RADAR and the internal sphincter alone for the combined dataset. Incontinence was also strongly correlated with dose from posterior oblique beams. Patients with fields extending inferiorly and posteriorly to the CTV, adjacent to the membranous and spongy urethra, were found to experience increased frequency. Conclusions: Anatomically-localized dose-toxicity relationships were determined for late genitourinary symptoms in the urethra and urinary sphincters. Low-intermediate doses to the extraprostatic urethra were associated with risk of late dysuria and haematuria, while dose to the urinary sphincters was associated with incontinence.

Preservation of the mesureter to reduce urinary complications: analysis of data from the observational Leipzig School MMR study

OBJECTIVE

To evaluate the feasibility and effect of mesureteral preservation on urinary complications in the context of total mesometrial resection (TMMR), a surgical treatment for cervical cancer.

DESIGN

Retrospective cohort study with historic control.

SETTING

Single tertiary academic centre.

POPULATION

Women older than 18 with primary cervical cancer staged FIGO IB1-IIB enrolled in the prospective Leipzig School MMR study and underwent total mesometrial resection (TMMR) without adjuvant radiation.

METHOD

We retrospectively analysed 100 consecutive TMMR procedures which were performed for cancer of the uterine cervix and in which the mesureter was preserved (intervention group, 01/2014-06/2017). We compared this group with the previous 100 consecutive TMMRs, which were performed before the introduction of mesureteral preservation (control group, 09/2010-01/2014).

MAIN OUTCOME MEASURES

The occurrence of urological and specifically ureteral complications.

RESULTS

Mesureteral preservation was feasible and was associated with a significant decrease in ureteral complications (11% without mesureteral preservation versus 3% with mesureteral preservation, P = 0.049). Furthermore, we found a significant decrease in the number of postoperative percutaneous nephrostomies and re-operations (7% versus none, P = 0.014). There was also a trend towards a decrease in other urinary complications such as postoperative bladder atony and uretero-vaginal fistulas.

CONCLUSION

The mesureter constitutes a convenient dissection plane enabling the preservation of lateral ureteral blood supply during TMMR. In our study, maintenance of mesureteral integrity was associated with a significant reduction in ureteral complications. Mesureteral preservation might also be useful in other types of pelvic surgeries that carry a high risk of ureteral damage.

TWEETABLE ABSTRACT

Surgical preservation of the mesureter in cervical cancer patients was associated with a reduction in urinary complications.

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.

An Effective Meta-analysis of Magnetic Stimulation Therapy for Urinary Incontinence

Magnetic stimulation (MS) is a novel approach for treating urinary incontinence (UI), but its applicability remains unclear. This systematic review and meta-analysis were conducted to evaluate the effects of MS treatment on UI. A literature search was performed in EMBASE, PubMed and Cochrane Library (from May 2018 to August 2018), and all randomized control trials (RCTs) published in English were screened to determine whether they met the inclusion criteria. A manual search of the reference lists of the retrieved studies was also performed. Eleven studies involving 612 patients were included in this review. According to the results of the meta-analysis, MS therapy relieved UI symptoms evaluated using the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) score (mean difference [MD] -3.03, 95% CI -3.27 to -2.79). In addition, the frequency of UI in the MS treatment group was also alleviated compared with sham group (MD -1.42, 95% CI -2.15 to -0.69). Finally, MS treatment improved the quality of life of patients with UI (standardized mean difference [SMD] -1.00, 95% CI -1.24 to -0.76). Our meta-analysis preliminarily indicates that MS treatment is an effective therapeutic modality for patients with UI. Nevertheless, additional large, high quality RCTs with a longer follow-up period that use consistent stimulation methods and analyse comparable outcomes are required to validate the efficacy.

Sex differences in lower urinary tract biology and physiology

Females and males differ significantly in gross anatomy and physiology of the lower urinary tract, and these differences are commonly discussed in the medical and scientific literature. However, less attention is dedicated to investigating the varied development, function, and biology between females and males on a cellular level. Recognizing that cell biology is not uniform, especially in the lower urinary tract of females and males, is crucial for providing context and relevance for diverse fields of biomedical investigation. This review serves to characterize the current understanding of biological sex differences between female and male lower urinary tracts, while identifying areas for future research. First, the differences in overall cell populations are discussed in the detrusor smooth muscle, urothelium, and trigone. Second, the urethra is discussed, including anatomic discussions of the female and male urethra followed by discussions of cellular differences in the urothelial and muscular layers. The pelvic floor is then reviewed, followed by an examination of the sex differences in hormonal regulation, the urinary tract microbiome, and the reticuloendothelial system. Understanding the complex and dynamic development, anatomy, and physiology of the lower urinary tract should be contextualized by the sex differences described in this review.

Mechanical relationship of filum terminale externum and filum terminale internum: is it possible to detether the spinal cord extradurally?

INTRODUCTION

Intradural transection of the filum terminale (FTI) is often used to treat tethered cord syndrome. Recently, some have proposed that the extradural part of the filum terminale (FTE) can be sectioned with equal results but with fewer complications. Therefore, the present cadaveric study aimed to evaluate the anatomical foundation of such procedures.

METHODS

A posterior lumbosacral approach was performed on five fresh-frozen cadaveric specimens to expose both the FTI and FTE. Tension was then applied to the FTE and observations and measurements made of any movement of the FTI. Other morphological measurements (e.g., length, diameter) of the FTI and FTE were also made.

RESULTS

Although very minimal movement of the FTI was seen in the majority of specimens following tension on the FTE, no specimen was found to have more cranial movement of the conus medullaris or cauda equina. The mean length and diameter of the FTI was 52.2 and 0.38 mm, respectively. The mean length and diameter of the FTE was 77 and 0.60 mm, respectively. The force necessary to move the FTI with tension applied to the FTE had a mean of 0.03 N. The average distance that the FTI moved with distal FTE tension was 1.33 mm. All specimens had a thecal sac that terminated at the S2 vertebral level. And no specimen had a low-lying conus medullaris, cutaneous stigmata of occult spinal dysraphism, or grossly visible adipose tissue in either the FTI or FTE.

CONCLUSIONS

Based on our studies, tension placed on the FTE has very little effect on the FTI and no obvious effect on the conus medullaris or cauda equina. Therefore, isolated transection of the FTE for a patient with tethered cord syndrome is unlikely to have significant effect. To our knowledge, this is the first study to quantitate the distal forces needed on the FTE to move the FTI.

Reconstruction of Membranous Urethral Strictures

PURPOSE OF REVIEW

Due to the proximity of the rhabdosphincter and cavernous nerves to the membranous urethra, reconstruction of membranous urethral stricture implies a risk of urinary incontinence and erectile dysfunction. To avoid these complications, endoscopic management of membranous urethral strictures is traditionally favored, and bulboprostatic anastomosis is reserved as the main classical approach for open reconstruction of recalcitrant membranous urethral stricture. The preference for the anastomotic urethroplasty among reconstructive urologists is likely influenced by the familiarity and experience with trauma-related injuries. We review the literature focusing on the anatomy of membranous urethra and on the evolution of treatments for membranous urethral strictures.

RECENT FINDINGS

Non-traumatic strictures affecting bulbomembranous urethra are typically sequelae of instrumentation, transurethral resection of the prostate, prostate cancer treatment, and pelvic irradiation. Being a different entity from trauma-related injuries where urethra is not in continuity, a new understanding of membranous urethral anatomy is necessary for the development of novel reconstruction techniques. Although efficacious and durable to achieve urethral patency, classical bulboprostatic anastomosis carries a risk of de-novo incontinence and impotence. Newer and relatively less invasive reconstructive alternatives include bulbar vessel-sparing intra-sphincteric bulboprostatic anastomosis and buccal mucosa graft augmented membranous urethroplasty techniques. The accumulated experience with these techniques is relatively scarce, but several published series present promising results. These approaches are especially indicated in patients with previous transurethral resection of the prostate in which sparing of rhabdosphincter and the cavernous nerves is important in attempt to preserve continence and potency. Additionally, introduction of buccal mucosa onlay grafts could be especially beneficial in radiation-induced strictures to avoid transection of the sphincter in continent patients, and to preserve the blood supply to the urethra for incontinent patients who will require artificial urinary sphincter placement. The evidence regarding erectile functional outcomes is less solid and this item should be furtherly investigated.

Central control of micturition in women: Brain-bladder pathways in continence and urgency urinary incontinence

Urinary incontinence disproportionately affects women. Anatomical textbooks typically describe continence mechanisms in women in the context of the pelvic floor support of the urinary bladder and the urethral sphincters. However, the urinary bladder and urethral sphincters are under the central control of the brain through a complex network of neurons that allow storage of urine followed by voiding when socially appropriate. Recent studies suggest that the most common type of urinary incontinence in women, urgency urinary incontinence, involves significant dysfunction of the central control of micturition. In this paper, we review the anatomy and functional connectivity of the nervous system structures involved in the control of micturition. Clinical application of this anatomy in the context of urgency urinary incontinence is also discussed. Understanding the anatomy of the neural structures that control continence will allow clinicians to better understand the underlying pathology of urge incontinence and consider new ways of treating this distressing condition. Clin. Anat. 30:373-384, 2017. © 2017 Wiley Periodicals, Inc.

Three-dimensional translabial ultrasound assessment of urethral supports and the urethral sphincter complex in stress urinary incontinence

AIMS

The pathophysiological mechanism of incontinence is multifactorial. We evaluated the role of 3D-4D ultrasound in the assessment of the fascial supports of the urethra and the urethral sphincter complex (USC) for diagnosing stress urinary incontinence.

METHODS

Observational case-control study in women with and without stress urinary incontinence attending a urogynecology service and a general gynecology service. All women were interviewed, examined, and classified according to the Pelvic Organ Prolapse Quantification (POP-Q) and underwent a 3D-4D translabial ultrasound. Fascial supports of the urethra were assessed by tomographic ultrasound and were considered to be intact or absent if it was possible to identify them at eight levels on each side, urethral mobility was assessed on maximal Valsalva in sagittal section and the length and volume of the USC at rest and on maximal Valsalva were determined using the Virtual Organ Computer-aided Analysis (VOCAL) program. Variables were compared between continent and incontinent women.

RESULTS

A total of 173 women were examined, 78 continent and 95 incontinent. There was a significant difference in urethral mobility between continent and incontinent women (12.82 mm vs. 21.85 mm, P < 0.001), but there was no significant difference in the percentage of supports affected (43.27% vs. 35.94%, P < 0.070). The length of the USC at rest was significantly shorter (P < 0.001) ​​in incontinent patients.

CONCLUSIONS

Ultrasound evaluation of urethral supports does not discriminate between continent and incontinent women. However, the length of the USC at rest was shorter and urethral mobility was higher in incontinent women. Neurourol. Urodynam. 9999:XX-XX, 2016. © 2016 Wiley Periodicals, Inc.

Magnetic resonance imaging-guided functional anatomy approach to prostate brachytherapy

PURPOSE

To provide an MRI based functional anatomy guide to prostate brachytherapy.

METHODS AND MATERIALS

We performed a narrative review of periprostatic functional anatomy and the significance of this anatomy in prostate brachytherapy treatment planning.

RESULTS

MRI has improved delineation of gross tumor and critical periprostatic structures that have been implicated in toxicity. Furthermore, MRI has revealed the significant anatomic variants and the dynamic nature of these structures that can have significant implications for treatment planning and dosimetry.

CONCLUSIONS

The MRI-based functional anatomy approach to prostate brachytherapy takes into account extent of disease, its relation to the patient's individual anatomy, and functional baseline to optimize the therapeutic ratio of prostate cancer treatment.

Future Perspectives in Bladder Tissue Engineering

Substantial clinical need persists for improved autologous tissues to augment or replace the urinary bladder and research has begun to address this using tissue engineering techniques. The implantation of both tissue scaffolds which allow for native bladder tissue ingrowth and autologous bladder grafts created from in vitro cellularization of such scaffolds have been tested clinically; however, successful outcomes in both scenarios have been challenged by insufficient vascularity resulting from large graft sizes, which subsequently limits tissue ingrowth and leads to central graft ischemia. Consequently, recent research has focused on developing better methods to produce scaffolds with increased tissue ingrowth and vascularity. This review provides an update on bladder tissue engineering and outlines the challenges that remain to clinical implementation.

Cell Therapy for Stress Urinary Incontinence

Urinary incontinence (UI) is the involuntary loss of urine and is a common condition in middle-aged and elderly women and men. Stress urinary incontinence (SUI) is caused by leakage of urine when coughing, sneezing, laughing, lifting, and exercise, even standing leads to increased intra-abdominal pressure. Other types of UI also exist such as urge incontinence (also called overactive bladder), which is a strong and unexpected sudden urge to urinate, mixed forms of UI that result in symptoms of both urge and stress incontinence, and functional incontinence caused by reduced mobility, cognitive impairment, or neuromuscular limitations that impair mobility or dexterity. However, for many SUI patients, there is significant loss of urethral sphincter muscle due to degeneration of tissue, the strain and trauma of pregnancy and childbirth, or injury acquired during surgery. Hence, for individuals with SUI, a cell-based therapeutic approach to regenerate the sphincter muscle offers the advantage of treating the cause rather than the symptoms. We discuss current clinically relevant cell therapy approaches for regeneration of the external urethral sphincter (striated muscle), internal urethral sphincter (smooth muscle), the neuromuscular synapse, and blood supply. The use of mesenchymal stromal/stem cells is a major step in the right direction, but they may not be enough for regeneration of all components of the urethral sphincter. Inclusion of other cell types or biomaterials may also be necessary to enhance integration and survival of the transplanted cells.

Stress urinary incontinence animal models as a tool to study cell-based regenerative therapies targeting the urethral sphincter

Urinary incontinence (UI) is a major health problem causing a significant social and economic impact affecting more than 200million people (women and men) worldwide. Over the past few years researchers have been investigating cell therapy as a promising approach for the treatment of stress urinary incontinence (SUI) since such an approach may improve the function of a weakened sphincter. Currently, a diverse collection of SUI animal models is available. We describe the features of the different models of SUI/urethral dysfunction and the pros and cons of these animal models in regard to cell therapy applications. We also discuss different cell therapy approaches and cell types tested in preclinical animal models. Finally, we propose new research approaches and perspectives to ensure the use of cellular therapy becomes a real treatment option for SUI.