Anatomy of muscle connections in the male urethra and anorectal canal

OBJECTIVES

To elucidate the male urethral muscular structure and its relationship with the anorectal canal muscles, as establishing an anatomical foundation for urethral function will contribute to the prevention, diagnosis, and treatment of urinary incontinence.

METHODS

Eight male cadavers were used. Using a multifaceted approach, we performed macroscopic anatomical examination, histological analysis of wide-range serial sectioning and immunostaining, and three-dimensional (3D) reconstruction from histological sections. In the macroscopic anatomical examination, pelvic halves were meticulously dissected in layers from the medial aspect. In the histological analysis, the tissue, including the urethra and anorectal canal, was serially sectioned in the horizontal plane. The muscular structures were reconstructed and visualised in 3D.

RESULTS

The membranous portion of the urethra had three muscle layers: the longitudinal and circular muscles (smooth muscle) and the external urethral sphincter (skeletal muscle). The circular muscle was connected posteriorly to the longitudinal rectal muscle. The external urethral sphincter had a horseshoe shape, with its posterior ends continuing to the external anal sphincter, forming a 3D ring-like sphincter.

CONCLUSION

This study revealed skeletal and smooth muscle connections between the male urethra and anorectal canal, enabling urethral compression and closure. These anatomical muscle connections suggest a functional linkage between them.

Disagreement in Female Urethral Nomenclature: A Survey Study of Genitourinary Surgeons

Inconsistencies have existed in the literature pertaining to the usage of the terms "dorsal" and "ventral" to describe the female urethra for years. The authors designed a survey study to demonstrate this inconsistency amongst genitourinary surgeons. When asked to label the dorsal urethra, 48% of respondents correctly labeled it as "dorsal," 27% incorrectly labeled it as "ventral," and 25% elected to write-in a response. When asked to label the ventral urethra, 52% of respondents correctly labeled it as "ventral," 26% incorrectly labeled it as "dorsal," and 22% elected to write-in a response.The significant mislabeling of the female urethra provides rationale for establishing standardized terminology. This nomenclature confusion has been a poorly addressed issue lurking in the genitourinary literature for decades with an article published in the Journal of Urology dating back as early as 2005 showing the use of this improper terminology. We cannot continue to ignore this problem and must do better as a community to remedy this as soon as possible with increased recognition and intervention by large societies, and more explicit descriptors in textbooks highlighting female urethral anatomy.

Advances in 3D bioprinting for urethral tissue reconstruction

Urethral conditions affect children and adults, increasing the risk of urinary tract infections, voiding and sexual dysfunction, and renal failure. Current tissue replacements differ from healthy urethral tissues in structural and mechanical characteristics, causing high risk of postoperative complications. 3D bioprinting can overcome these limitations through the creation of complex, layered architectures using materials with location-specific biomechanical properties. This review highlights prior research and describes the potential for these emerging technologies to address ongoing challenges in urethral tissue engineering, including biomechanical and structural mismatch, lack of individualized repair solutions, and inadequate wound healing and vascularization. In the future, the integration of 3D bioprinting technology with advanced biomaterials, computational modeling, and 3D imaging could transform personalized urethral surgical procedures.

Ultrasound for the evaluation of the urethra in pediatric patients

Urethral lesions in pediatric patients can be visualized using ultrasonography. Therefore, sonographers and physicians should be familiar with the technique.

Expression and localization of the mechanosensitive/osmosensitive ion channel TMEM63B in the mouse urinary tract

The epithelial cells that line the kidneys and lower urinary tract are exposed to mechanical forces including shear stress and wall tension; however, the mechanosensors that detect and respond to these stimuli remain obscure. Candidates include the OSCA/TMEM63 family of ion channels, which can function as mechanosensors and osmosensors. Using Tmem63bHA-fl/HA-fl reporter mice, we assessed the localization of HA-tagged-TMEM63B within the urinary tract by immunofluorescence coupled with confocal microscopy. In the kidneys, HA-TMEM63B was expressed by proximal tubule epithelial cells, by the intercalated cells of the collecting duct, and by the epithelial cells lining the thick ascending limb of the medulla. In the urinary tract, HA-TMEM63B was expressed by the urothelium lining the renal pelvis, ureters, bladder, and urethra. HA-TMEM63B was also expressed in closely allied organs including the epithelial cells lining the seminal vesicles, vas deferens, and lateral prostate glands of male mice and the vaginal epithelium of female mice. Our studies reveal that TMEM63B is expressed by subsets of kidney and lower urinary tract epithelial cells, which we hypothesize are sites of TMEM63B mechanosensation or osmosensation, or both.

Nitrergic inhibition of sympathetic arteriolar constrictions in the female rodent urethra

During the urine storage phase, tonically contracting urethral musculature would have a higher energy consumption than bladder muscle that develops phasic contractions. However, ischaemic dysfunction is less prevalent in the urethra than in the bladder, suggesting that urethral vasculature has intrinsic properties ensuring an adequate blood supply. Diameter changes in rat or mouse urethral arterioles were measured using a video-tracking system. Intercellular Ca2+ dynamics in arteriolar smooth muscle (SMCs) and endothelial cells were visualised using NG2- and parvalbumin-GCaMP6 mice, respectively. Fluorescence immunohistochemistry was used to visualise the perivascular innervation. In rat urethral arterioles, sympathetic vasoconstrictions were predominantly suppressed by α,β-methylene ATP (10 μM) but not prazosin (1 μM). Tadalafil (100 nM), a PDE5 inhibitor, diminished the vasoconstrictions in a manner reversed by N-ω-propyl-l-arginine hydrochloride (l-NPA, 1 μM), a neuronal NO synthesis (nNOS) inhibitor. Vesicular acetylcholine transporter immunoreactive perivascular nerve fibres co-expressing nNOS were intertwined with tyrosine hydroxylase immunoreactive sympathetic nerve fibres. In phenylephrine (1 μM) pre-constricted rat or mouse urethral arterioles, nerve-evoked vasodilatations or transient SMC Ca2+ reductions were largely diminished by l-nitroarginine (l-NA, 10 μM), a broad-spectrum NOS inhibitor, but not by l-NPA. The CGRP receptor antagonist BIBN-4096 (1 μM) shortened the vasodilatory responses, while atropine (1 μM) abolished the l-NA-resistant transient vasodilatory responses. Nerve-evoked endothelial Ca2+ transients were abolished by atropine plus guanethidine (10 μM), indicating its neurotransmitter origin and absence of non-adrenergic non-cholinergic endothelial NO release. In urethral arterioles, NO released from parasympathetic nerves counteracts sympathetic vasoconstrictions pre- and post-synaptically to restrict arteriolar contractility. KEY POINTS: Despite a higher energy consumption of the urethral musculature than the bladder detrusor muscle, ischaemic dysfunction of the urethra is less prevalent than that of the bladder. In the urethral arterioles, sympathetic vasoconstrictions are predominately mediated by ATP, not noradrenaline. NO released from parasympathetic nerves counteracts sympathetic vasoconstrictions by its pre-synaptic inhibition of sympathetic transmission as well as post-synaptic arteriolar smooth muscle relaxation. Acetylcholine released from parasympathetic nerves contributes to endothelium-dependent, transient vasodilatations, while CGRP released from sensory nerves prolongs NO-mediated vasodilatations. PDE5 inhibitors could be beneficial to maintain and/or improve urethral blood supply and in turn the volume and contractility of urethral musculature.

Innovative decision making tools using discrete mathematics for stress urinary incontinence treatment

In this study, we applied graph theory to clinical decision-making for Stress Urinary Incontinence (SUI) treatment. Utilizing discrete mathematics, we developed a system to visually understand the shortest path to the desired treatment outcomes by considering various patient variables. Focusing on women aged 35-50, we examined the effectiveness of Tension-free Vaginal Tape (TVT) surgery and Vaginal Erbium Laser (VEL) treatment for over 15 years. The TVT group consisted of 102 patients who underwent surgery using either the Advantage Fit mid-urethral sling system (Boston Scientific Co., MA, USA) or the GYNECARE TVT retropubic system (Ethicon Inc., NJ, USA). The VEL group included 113 patients treated with a non-ablative Erbium: YAG laser (FotonaSmooth™ XS; Fotona d.o.o., Ljubljana, Slovenia), and there were 112 patients in the control group. We constructed a network diagram analyzing the correlations between health, demographic factors, treatment methods, and patient outcomes. By calculating the shortest path using heuristic functions, we identified significant correlations and treatment effects. This approach supports patient decision making by choosing between TVT and VEL treatments based on individual objectives. Our findings provide new insights into SUI treatment, highlighting the value of a data-driven personalized approach for clinical decision-making. This interdisciplinary study bridges the gap between mathematics and medicine, demonstrating the importance of a data-centric approach in clinical decisions.

Primary mucinous adenocarcinoma of the urethra: A clinicopathological analysis of 35 cases

AIM

Primary mucinous adenocarcinoma of the urethra represents an extremely rare entity. We sought to characterise further these tumours' clinicopathological, immunohistochemical and molecular features.

METHODS AND RESULTS

Thirty-five cases were identified, occurring in 18 males and 17 females. The mean age at diagnosis was 65 years (28-89 years). The main presentation symptoms were haematuria and urinary outlet obstruction. Microscopic analysis revealed that all 35 tumours have stromal dissection by mucin. Ten tumours showed villoglandular dysplasia, nine showed mucinous metaplasia, two showed adenocarcinoma in situ and four showed signet ring cell features. All tumours were immunopositive for CEA, while immunonegative for nuclear β-catenin; 19 of 23 (83%) expressed high molecular weight cytokeratin; 19 of 33 (58%) CK7; 28 of 34 (82%) CK20; 32 of 35 (91%) CDX2; 22 of 27 (81%) cadherin-17 (CDH-17); 26 of 29 (90%) SATB2; and one of 31 (3%) GATA3. Mismatch repair gene products, including MLH1, PMS2, MSH2 and MSH6, were immunopositive, suggesting the MSI-low genotype of mucinous adenocarcinoma of the urethra. BRAF V600E and ALK rearrangements were not detected. During the mean follow-up of 20 months, nine patients either developed distant metastasis or succumbed to the illness.

CONCLUSION

Our study, encompassing the most extensive series of 35 cases of primary mucinous adenocarcinoma of the urethra, provides crucial insights into its precise diagnosis, management and potential targeted treatments. We found a greater CDX2, SATB2 and CDH17 sensitivity in these urethral tumours for the first time, to our knowledge. We identified characteristics such as an MSI-low profile, non-V600E BRAF mutations and an absence of ALK rearrangements.

Isolated Male Epispadias Repair: Long-Term Outcomes

Isolated male epispadias is one of the most severe congenital genital anomalies that require surgical correction. The goals of the surgery are to reach good aesthetic and functional outcomes. The aim of this retrospective study was to analyze the long-term outcomes of surgical reconstruction of male epispadias. A total of 31 patients with a mean age of 17 years, who underwent surgical repair of isolated male epispadias from January 2000 to January 2015, were involved. The main outcome measures were defined as: aesthetic outcome, continence, postoperative complications, sexual function, and quality of life. The follow-up period ranged from 8 to 23 years, with an average of 14.4 years. Each patients underwent an average of 2.2 surgical procedures in this period. The most common postoperative complications were urethral fistula and residual curvature, in 22.6% and 12.9%, respectively. Satisfactory aesthetic outcome was reported in 71.4% of cases. The repair of male epispadias usually includes more than two procedures with satisfactory aesthetic outcome. Unsolved urinary incontinence remains a significant issue and has a high impact on the quality of life. Follow-up should be extended even after complete sexual maturity. Comprehensive long-term evaluation is necessary for proper treatment of isolated epispadias.

Symmetric dimethylarginine correlates with the urea, creatinine, potassium, and clinical scores in feline urethral obstructions

BACKGROUND

A urethral obstruction (UO) is an emergency commonly observed in male cats, which can result in significant clinical and laboratory alterations, leading to complications and death.

OBJECTIVES

This study aimed to correlate symmetric dimethylarginine (SDMA) with the urea, creatinine, potassium, and bicarbonate levels in cats with UO. In addition, the correlation between clinical score and time of obstruction was evaluated.

METHODS

Thirty male cats were selected and allocated into a control group (CG, n = 13) and an obstruction group (OG, n = 17). The laboratory analyses were conducted before treatment (M0) and at different times after treatment (12 h [M12], 24 h [M24], and 48 h [M48]). Correlations were established between SDMA and creatinine, urea, bicarbonate, potassium, time of obstruction, and the clinical score.

RESULTS

A strong correlation (r > 0.6) was observed between SDMA and creatinine, urea, and potassium in the OG. Furthermore, there was substantial agreement (kappa value) between SDMA and creatinine at M24. A higher clinical score was associated with a longer time of obstruction. In the OG, at M48, the SDMA and creatinine levels were 50% and 41.2% higher, respectively.

CONCLUSIONS

A correlation was observed between SDMA and creatinine in obstructed cats, and significant agreement between these values was observed 24 h after the unblocking treatment. A correlation among SDMA, urea, and potassium was observed. Approximately 9% more cats continued to have elevated SDMA levels after 48 h of treatment compared to creatinine. This suggests a slightly lower sensitivity of the latter biomarker but does not exclude the possibility of congruent and normalized values after a longer evaluation period.

Age-Related Changes in Urethral Structure and Responds to Injury: Single-Cell Atlas of a Rat Model of Vaginal Birth Injury induced Stress Urinary Incontinence

Stress urinary incontinence (SUI) greatly affects the daily life of numerous women and is closely related to a history of vaginal delivery and aging. We used vaginal balloon dilation to simulate vaginal birth injury in young and middle-aged rats to produce a SUI animal model, and found that young rats restored urethral structure and function well, but not the middle-aged rats. To identify the characteristics of cellular and molecular changes in the urethral microenvironment during the repair process of SUI. We profiled 51,690 individual female rat urethra cells from 24 and 48 weeks old, with or without simulated vaginal birth injury. Cell interaction analysis showed that signal networks during repair process changed from resting to active, and aging altered the distribution but not the overall level of cell interaction in the repair process. Similarity analysis showed that muscle, fibroblasts, and immune cells underwent large transcriptional changes during aging and repair. In middle-aged rats, cell senescence occurs mainly in the superficial and middle urothelium due to cellular death and shedding, and the basal urothelium expressed many Senescence-Associated Secretory Phenotype (SASP) genes. In conclusion, we established the aging and vaginal balloon dilation (VBD) model of female urethral cell anatomy and the signal network landscape, which provides an insight into the normal or disordered urethra repair process and the scientific basis for developing novel SUI therapies.

An assessment of the relationship between urethral hypermobility as measured by ultrasound and the symptoms of stress urinary incontinence in primiparous women 9-18 months postpartum

Aim

The aim of the study was to estimate the relationship between bladder neck hypermobility as assessed by ultrasound and the occurrence of stress urinary incontinence as measured with the UDI-6 questionnaire in primiparous women 9-18 months postpartum.

Materials and methods

The study included 100 women 9-18 months after their first delivery, 19% of whom (study group) presented with urethral hypermobility. Ultrasound was used to determine the position and mobility of the bladder neck in order to assess the urethral hypermobility. A vector of ≥15 mm was defined as urethral hypermobility. Symptoms of stress urinary incontinence were assessed using question 3 of the UDI-6 questionnaire, in which the presence of symptoms was defined as a response rated from 1 to 4.

Results

We demonstrated a statistically significant relationship between urethral hypermobility and the symptoms of stress urinary incontinence with a statistical significance level of p <0.002.

Conclusions

Stress urinary incontinence is a common disorder in women, the pathophysiology of which is not fully understood. It has adverse effects on the quality of life, perception of one's own body and sexual function. Impairment of urethral fixation may play an important role in the pathophysiology of this common form of urinary incontinence. The study showed that urethral hypermobility, as assessed by ultrasound, contributes to stress urinary incontinence, as measured with the UDI-6 score. Although stress urinary incontinence is a multifactorial disorder influenced by anatomical changes and congenital anatomical features, it is easily diagnosed. Suburethral slings are an effective surgical technique; however, the incidence of postoperative voiding dysfunction or recurrent stress urinary incontinence is 10-20%. Therefore, an assessment of anatomical changes in stress urinary incontinence may help individualize the surgical strategy.

Dosimetric predictors for genitourinary toxicity in MR-guided stereotactic body radiation therapy (SBRT): Substructure with fraction-wise analysis

BACKGROUND

MR-guided radiation therapy (MRgRT) systems provide superior soft tissue contrast than x-ray based systems and can acquire real-time cine for treatment gating. These features allow treatment planning margins to be reduced, allowing for improved critical structure sparing and reduced treatment toxicity. Despite this improvement, genitourinary (GU) toxicity continues to affect many patients.

PURPOSE

(1) To identify dosimetric predictors, potentially in combination with clinical parameters, of GU toxicity following SBRT by leveraging MRgRT to accurately monitor daily dose, beyond predicted dose calculated during planning. (2) Improve awareness of toxicity-sensitive bladder substructures, specifically the trigone and urethra.

METHODS

Sixty-nine prostate cancer patients (NCT04384770 clinical trial) were treated on a ViewRay MRIdian MRgRT system, with 40 Gy prescribed to 95% of the PTV in over five fractions. Overall, 17 (24.6%) prostate patients reported acute grade 2 GU toxicity. The CTV, PTV, bladder, bladder wall, trigone, urethra, rectum, and rectal wall were contoured on the planning and daily treatment MRIs. Planning and daily treatment DVHs (0.1 Gy increments), organ doses (min, max, mean), and organ volumes were recorded. Daily dose was estimated by transferring the planning dose distributions to the daily MRI based on the daily setup alignment. Patients were partitioned into a training (55) and testing set (14). Dose features were pre-filtered using a t-test followed by maximum relevance minimum redundancy (MRMR) algorithm. Logistic regression was investigated with regularization to select dosimetric predictors. Specifically, two approaches: time-group least absolute shrinkage and selection (LASSO), and interactive grouped greedy algorithm (IGA) were investigated. Shared features across the planning and five treatment fractions were grouped to encourage consistency and stability. The conventional flat non-temporally grouped LASSO was also evaluated to provide a solid benchmark. After feature selection, a final logistic regression model was trained. Dosimetric regression models were compared to a clinical regression model with only clinical parameters (age, baseline IPSS, prostate gland size, ADT usage, etc.) and a hybrid model, combining the best performing dosimetric features with the clinical parameters, was evaluated. Final model performance was evaluated on the testing set using accuracy, sensitivity, and specificity determined by the optimal threshold of the training set.

RESULTS

IGA had the best testing performance with an accuracy/sensitivity/specificity of 0.79/0.67/0.82, selecting 12 groups covering the bladder (V19.8 Gy, V20.5 Gy), bladder wall (19.7 Gy), trigone (15.9, 18.2, 43.3 Gy), urethra (V41.4 Gy, V41.7 Gy), CTV (V41.9 Gy), rectum (V8.5 Gy), and rectal wall (1.2, 44.1 Gy) dose features. Absolute bladder V19.8 Gy and V20.5 Gy were the most important features, followed by relative trigone 15.9  and 18.2 Gy. Inclusion of clinical parameters in the hybrid model with IGA did not significantly change regression performance.

CONCLUSION

Overall, IGA feature selection resulted in the best GU toxicity prediction performance. This exploratory study demonstrated the feasibility of identification and analysis of dosimetric toxicity predictors with awareness to sensitive substructures and daily dose to potentially provide consistent and stable dosimetric metrics to guide treatment planning. Further patient accruement is warranted to further assess dosimetric predictor and perform validation.

Congenital Urethrocutaneous Fistula

ABSTRACT

Male congenital urethrocutaneous fistula is an extremely rare anomaly that is commonly associated with chordee or anorectal malformations. It is characterised by an abnormal urethral opening on the ventral aspect of the penis with well-formed distal urethra and meatus at the tip of the glans. The treatment is individualised according to the site of the fistula, associated anomalies and condition of the distal urethra. The principles of hypospadias surgery should be strictly followed.

Is the time right for a new initiative in mathematical modeling of the lower urinary tract? ICI-RS 2023

INTRODUCTION

A session at the 2023 International Consultation on Incontinence - Research Society (ICI-RS) held in Bristol, UK, focused on the question: Is the time right for a new initiative in mathematical modeling of the lower urinary tract (LUT)? The LUT is a complex system, comprising various synergetic components (i.e., bladder, urethra, neural control), each with its own dynamic functioning and high interindividual variability. This has led to a variety of different types of models for different purposes, each with advantages and disadvantages.

METHODS

When addressing the LUT, the modeling approach should be selected and sized according to the specific purpose, the targeted level of detail, and the available computational resources. Four areas were selected as examples to discuss: utility of nomograms in clinical use, value of fluid mechanical modeling, applications of models to simplify urodynamics, and utility of statistical models.

RESULTS

A brief literature review is provided along with discussion of the merits of different types of models for different applications. Remaining research questions are provided.

CONCLUSIONS

Inadequacies in current (outdated) models of the LUT as well as recent advances in computing power (e.g., quantum computing) and methods (e.g., artificial intelligence/machine learning), would dictate that the answer is an emphatic "Yes, the time is right for a new initiative in mathematical modeling of the LUT."

[Regnerative technologies in reconstructive operations on the urethra: a review. Part 2]

Recent advances in the treatment of urethral strictures are associated with regenerative medicine and tissue engineering. Urethral reconstruction in some cases is a difficult task for urologists due to the insufficient amount of autologous tissue and relapses, which encourages clinicians to search for alternatives. The purpose of this work is to review the latest achievements in the use of regenerative technologies, biomaterials and cell therapy in urethroplasty. The second part of the literature review presents the prospects of using the stromal vascular fraction (SVF) of autologous adipose tissue during reconstructive operations on the urethra, especially considering the availability of these cells through lipoaspiration. Tissue engineering technologies are reflected, which offer their own solutions to problems and limitations of their use. The article also provides examples of experimental studies in which cell-free and cellular biomaterials were used for urethral reconstruction. We believe that the approach of using SVF and biomatrix can become a potentially safe and effective method of therapy associated with the acceleration of regeneration processes, and can be of great benefit to patients with urethral diseases in the future.

Melanoma of glans penis and urethra: A case report and systematic review of the literature of a rare and complex neoplasm

OBJECTIVE

To evaluate the features and prognosis of melanoma of glans penis and urethra, with the presentation of a significant case report.

MATERIALS AND METHODS

A systematic literature review was performed using the MEDLINE (PubMed) and Cochrane Libraries databases to identify all cases of male mucosal melanoma reported.

RESULTS

Two hundred fifty-two patients with male mucosal primary melanoma were found. Glans penis and fossa navicularis as primary site includes the 81.6% of all lesions considered. Median Breslow's depth is 2.1 mm, whereas nine in situ melanomas have been reported. At the diagnosis, the disease was at a non-localized stage in 21.4% for glans penis melanomas and 11.7% urethral lesions, respectively. The 2 and 5-year survival for glans melanoma is 62.5% and 38.4%; higher rates were observed in the 2012-2020 period (76% and 58.8%, respectively). Two-year survival for urethral melanomas is 66.7%, while 5-year survival is 12.5%. 22 patients survived over 5 years with a Breslow's depth reported always < 3.3 mm.

CONCLUSION

Melanoma of the glans penis and urethra is a rare neoplasm associated with a poor prognosis, however recent reports show higher survival rates. Surgery remains the mainstay for a localized disease. Taking into account the small number of cases reported, topical imiquimod seems to be a valid non-surgical alterative for melanoma in situ. The use of immunotherapy and targeted therapy should be considered only in an adjuvant setting according to the recommendations of cutaneous melanoma; however, additional clinical data on male mucosal melanoma are needed to draw definitive conclusions.

Severe penile torsion of 180 degrees in an adult patient: a uro-radiological case report

Penile torsion is the abnormal three-dimensional twisting of penile corporal bodies. It can be classified as mild, moderate, or severe, depending on the degree of torsion. Severe penile torsion (>90°) is a very rare condition, with an estimated incidence of 0.4%-1% among all penile torsion cases. Our patient was a 37-year-old man complaining of a 2-year history of lower urinary tract symptoms. These symptoms appeared after the patient sustained an iatrogenic injury during Foley catheter insertion. Physical examination incidentally revealed an obvious counterclockwise penile rotation of 180°. Several theories have been proposed to explain the etiology of penile torsion, including theories based on genetic factors, abnormal urethral development, and abnormal attachment of the dartos fascia to the skin. Penile torsion may be associated with other penile anomalies, including chordee, hypospadias, and epispadias; however, it is often detected as an isolated finding. Clinical examination is sufficient to confirm its diagnosis without the need for further imaging. While no standardized procedure has been indicated for all penile torsion cases, the severity of torsion and the presence of other anomalies determine the most suitable procedure. No reports on the imaging features of penile torsion (irrespective of the degree of torsion) are available. We present the first such report on the imaging features, including advanced magnetic resonance imaging findings, of a 180° penile torsion in an adult patient.

A sewing needle as a urethral foreign body: A case report and literature review

Foreign bodies in the urethra can occur by self-insertion, and patients often hide the symptoms due to embarrassment. Foreign bodies act as a focus for infection and abscess formation and result in perforation or fistula when not detected on time. Foreign bodies can display symptoms such as frequent urination, dysuria, hematuria, urethrorrhagia, and obstruction. This case discusses a self-inserted urethral sewing needle that was removed cystoscopically from an adolescent.

Pharmacotherapy of urethral stricture

ABSTRACT

Urethral stricture is characterized by the chronic formation of fibrous tissue, leading to the narrowing of the urethral lumen. Despite the availability of various endoscopic treatments, the recurrence of urethral strictures remains a common challenge. Postsurgery pharmacotherapy targeting tissue fibrosis is a promising option for reducing recurrence rates. Although drugs cannot replace surgery, they can be used as adjuvant therapies to improve outcomes. In this regard, many drugs have been proposed based on the mechanisms underlying the pathophysiology of urethral stricture. Ongoing studies have obtained substantial progress in treating urethral strictures, highlighting the potential for improved drug effectiveness through appropriate clinical delivery methods. Therefore, this review summarizes the latest researches on the mechanisms related to the pathophysiology of urethral stricture and the drugs to provide a theoretical basis and new insights for the effective use and future advancements in drug therapy for urethral stricture.

Effect of Perineal Urethrostomy on the Length of the Urethra of the Cat: A Cadaveric Study

Perineal urethrostomy in cats is indicated for urethral pathologies located distal to the bulbourethral glands. The description of the bulbourethral glands as the cranial landmark when performing a PU is based on the increased urethral diameter at this location, rather than on an anatomical limitation. This suggests that urethral pathologies cranial to the bulbourethral glands could potentially be treated with PU. At present, the extent to which the pelvic urethra can be mobilized is unknown. Characterization and quantification of the effect of PU on the pelvic urethra is required prior to attempting to define the location of the pelvic urethra, cranial to the bulbourethral glands, which can be exteriorized when performing a PU. Our aim was to characterize and quantify the effect of performing a PU on the location and length of the pelvic urethra.

METHODS

Ten male feline cadavers were used, and four markers were placed on the pelvic urethra via a ventral approach to the peritoneal and pelvic cavities. Two orthogonal radiographic views were acquired prior and subsequent to performing a PU. The distance of each marker to a predefined landmark/origin and the distances of the markers relative to each other were measured on all radiographs.

RESULTS

PU resulted in significant caudal translation of the markers relative to the predefined landmark on all radiographic views; however, PU did not result in a significant change in the distances between the markers.

CONCLUSIONS

Performing a PU results in caudal translation and minimal stretching of the mobilized pelvic urethra.

Circular Penile Skin Fasciocutaneous Ventral Onlay Flap Urethroplasty as an Alternative to Dorsal Onlay Buccal Mucosal Graft Urethroplasty in Complex Long-Segment Urethral Stricture: A Retrospective Study

Background A urethral stricture is the narrowing of the urethra that results in symptoms of obstruction. It can appear anywhere along the male urethra's length and has a variety of causes. The circular penile fasciocutaneous flap is employed in the successful single-stage reconstruction of long-segment complex anterior urethral strictures especially when the buccal mucosa is unavailable due to various reasons. The study has tried to identify a surgical technique that is more beneficial for the treatment of urethral strictures. Objective The objective of this research was to evaluate the outcomes of circular penile skin fasciocutaneous ventral onlay flap urethroplasty (group A) and the outcomes of dorsal onlay buccal mucosal graft urethroplasty (group B) in the management of complex long-segment penile urethral stricture. Methods In this retrospective study between December 2012 and December 2022, 60 patients with long-segment complex penile urethral stricture who underwent urethroplasty at our center were evaluated. Patients were divided into two groups according to the flap used (dorsal onlay buccal mucosal graft urethroplasty was used in 30 patients (group B), and circular penile fasciocutaneous flap (single stage) was used in 30 patients (group A)). The success rate and the mean peak flow rate were also calculated post-operation to identify the effectiveness of the surgical procedure used for urethral strictures. Results The study consisted of 60 patients in total. Group A's mean age was determined to be 51.2±16.2 years, whereas group B's mean age was determined to be 40.7±16.8 years. Preoperatively, the median urethral stricture length was 69 mm in group A (range: 20-100 mm) and 56 mm in group B (range: 30-110 mm). The intraoperative median length of the urethral stricture was 82 mm in group A (range: 20-120 mm) and 65 mm in group B (range: 40-140 mm). The mean peak flow rate was 30.9±6.8 mL/s in group A compared to 18.1±4.9 mL/s in group B. The success rate for group A was 89.7%, while the success rate for group B was 75.9%. Conclusion For complex long-segment urethral strictures, circular penile skin fasciocutaneous ventral onlay flap urethroplasty has a higher rate of success and fewer complications than dorsal onlay buccal mucosal graft urethroplasty. Along with success rate, it has a better mean peak flow rate and lower complications.

Extracellular matrix stiffness aggravates urethral stricture through Igfbp3/Smad pathway

Urethral stricture refers to the narrowing of the urethral lumen. While previous studies have hinted at inflammation as the initial driver of this condition, the reasons and mechanisms behind its progression remain largely unknown. By Atomic force microscope (AFM), researchers measured the matrix stiffness of urethra to be 5.23 ± 0.37 kPa for normal tissue and 41.59 ± 2.48 kPa for stricture urethral scar. Similar results were observed in rat urethral stricture models, where the matrix stiffness of normal urethra was 4.29 ± 0.82 kPa, while 32.94 ± 7.12 kPa for urethral stricture scar. Notably, the matrix stiffness increased in rat models over time. To further investigate, polyacrylamide hydrogels were employed to mimic different levels of stiffness for normal and stricture condition. Interestingly, higher matrix stiffness led to an increased fibroblast-to-myofibroblast transition (FMT) in rat urethral fibroblasts, indicated by enhanced expression of α-SMA and Collagen I, as well as changing in the morphology of fibroblast. RNA-seq analysis suggested that Igfbp3/Smads might regulate the progressive FMT in urethral stricture. In the experiment where the expression of Igfbp3 was inhibited, increasing matrix stiffness lose the potential to stimulate FMT progression and the expression of p-Smad2/3 decreased. On the contrary, overexpression of Igfbp3 promoted the process of FMT in urethral fibroblasts. In conclusion, Igfbp3/Smad pathway appeared to be involved in the progression of urethral fibrosis. This finding suggested that Igfbp3/Smad might be an promising target for future research and treatment in this filed.

Labeling PIEZO2 activity in the peripheral nervous system

Sensory neurons detect mechanical forces from both the environment and internal organs to regulate physiology. PIEZO2 is a mechanosensory ion channel critical for touch, proprioception, and bladder stretch sensation, yet its broad expression in sensory neurons suggests it has undiscovered physiological roles. To fully understand mechanosensory physiology, we must know where and when PIEZO2-expressing neurons detect force. The fluorescent styryl dye FM 1-43 was previously shown to label sensory neurons. Surprisingly, we find that the vast majority of FM 1-43 somatosensory neuron labeling in mice in vivo is dependent on PIEZO2 activity within the peripheral nerve endings. We illustrate the potential of FM 1-43 by using it to identify novel PIEZO2-expressing urethral neurons that are engaged by urination. These data reveal that FM 1-43 is a functional probe for mechanosensitivity via PIEZO2 activation in vivo and will facilitate the characterization of known and novel mechanosensory processes in multiple organ systems.

Unusual intravesical foreign bodies: a report of two cases

The introduction of a foreign body into the urethra is an exceptionally rare occurrence. It is often secondary, either to erotic curiosity or to psychiatric disorders. The symptomatology is multiple and the diagnosis is aided by radiologic imaging. The extraction is most often done by endoscopic. The management of these patients must be done systematically and will need psychiatric assessment. We report the case of two patients who inserted a foreign body into their urinary bladder. One was 22-year-old and the second was 20-year-old and all with no history of psychiatric disorders. The first accidentally inserted a pencil into the urethra while trying to flatten a vulvar papule. The second inserted a piece of broom through playful games. The foreign bodies were extracted endoscopically in both cases under rachianesthesia. The postoperative course was uneventful and both patients were referred to a psychiatric clinic for evaluation after discharge.