The Surgical Learning Curve for One-stage Anterior Urethroplasty: A Prospective Single-surgeon Study

Clinical questions in the Japanese Urological Association's 2024 clinical practice guidelines for urethral strictures

Transurethral procedures such as direct vision internal urethrotomy and urethral dilation have been the traditional treatments for urethral strictures. However, transurethral procedures are associated with high recurrence rates, resulting in many uncured cases and prompting major international urological societies to recommend urethroplasty as the standard treatment owing to its high success rate. In contrast, many Japanese general urologists have little doubts about treating urethral strictures with transurethral treatment. Therefore, urethral stricture treatments in Japan are not in line with those used in other countries. To address this, the Trauma, Emergency Medicine, and Reconstruction Subcommittee of the Japanese Urological Association has developed guidelines to offer standardized treatment protocols for urethral stricture, based on international evidence and tailored to Japan's medical landscape. These guidelines target patients with a clinically suspected urethral stricture and are intended for urologists and general practitioners involved in its diagnosis and treatment. Following the Minds Clinical Practice Guideline Development Manual 2020, the committee identified eight critical clinical issues and formulated eight clinical questions using the "patient, intervention, comparison, and outcome" format. A comprehensive literature search was conducted. For six clinical questions addressed by the existing guidelines or systematic reviews, the level of evidence was determined by qualitative systematic reviews. Quantitative systematic reviews and meta-analyses were performed for the two unique clinical questions. The recommendation grades were determined using the Delphi method and consensus by the committee. These guidelines will be useful to clinicians in daily practice, especially those involved in the care of urethral strictures.

Current urethroplasty trends in recent GURS fellowship graduates

PURPOSE

To assess self-reported urethroplasty success rates and outcomes of recent GURS fellowship graduates and compare these data to the large body of published urethroplasty outcomes literature.

METHODS

A voluntary survey was distributed from June 1 to June 30, 2023 to GURS fellowship graduates of the last 5 years. Participants were surveyed on time since graduation, operative volume, outcomes, and quoted success rates for urethroplasty. Data were then analyzed using descriptive statistics, binary logistic regression, and correlative analyses.

RESULTS

We received responses from 49/101 (48.5%) GURS graduates. Five-year post-graduates were most represented (44.7%). The majority (52.2%) consider 81-90% of urethroplasty successful, without significant change with years in practice. Approximately 65% quoted excision and primary anastomosis (EPA) as > 90% successful. Over half of the respondents had performed > 60 urethroplasties since graduation. Only 31.3% of respondents reported re-intervening in > 10% of their postop patients, with a weak positive correlation between years in practice and need for re-intervention (p 0.01). Nearly 20% of respondents referred patients to an external reconstructionist.

CONCLUSION

Increased length of time in practice does not result in higher reported urethroplasty success rates, counseling on successful outcomes, or rates of re-intervention and complications. Our survey highlights that the traditionally used success rates for urethroplasty may not be reflective of new graduates and lower volume reconstructive surgeons in their early career.

A novel trauma induced urethral stricture in rat model

Urethral stricture (US) is a longstanding disease, while there has not existed a suitable animal model to mimic the condition. We aimed to establish a trauma-induced US animal model to simulate this clinical scenario. A total of 30 rats were equally distributed into two groups, sham and US group. All rats were anesthetized with isoflurane and undergone cystostomy. In the US group, a 2 mm incision was made in the urethra and sutured to induce US. The sham group only make a skin incision on the ventral side of the anterior urethra. 4 weeks later, ultrasound and cystourethrography were performed to evaluate the degree of urethral stricture, pathological examinations were carried out to evaluate the degree of fibrosis. Urodynamic evaluation and mechanical tissue testing were performed to evaluate the bladder function and urethral tissue stiffness. The results showed that the urethral mucosa was disrupted and urethral lumen was stenosed in the US group. Additionally, the US group showed elevated bladder pressure, prolonged micturition intervals and increased tissue stiffness. In conclusion, the rat urethral stricture model induced by trauma provides a closer representation of the real clinical scenario. This model will significantly contribute to advancing research on the mechanisms underlying traumatic urethral stricture.

Feasibility and Outcomes of Temporary Bulbar Urethral Stent Placement After Internal Urethrotomy in the Largest Multicenter Series

BACKGROUND

Recent years have seen the development of a new generation of temporary urethral stents as an adjuvant option after direct vision internal urethrotomy (DVIU). Despite some early promising results, large series addressing their safety and outcomes are still lacking.

OBJECTIVE

To report complications and outcomes from the largest series of patients receiving a temporary bulbar urethral stent to date.

DESIGN, SETTING, AND PARTICIPANTS

We performed a retrospective analysis of bulbar urethral stenting procedures after DVIU in seven centers. Patients either refused urethroplasty or were not fit for surgery. The stents were removed after at least 6 mo in place unless complications requiring earlier removal occurred.

SURGICAL PROCEDURE

DVIU with a cold knife or laser is performed, followed by stent placement. At the end of the treatment period, the stent is removed under cystoscopy with gripping forceps.

MEASUREMENTS

All patients underwent postoperative follow-up (FU) for assessment of complications while the stent was in place. After removal, the FU schedule consisted of office evaluation at 6 mo and 12 mo, and then annually. Failure was defined as any treatment for urethral stricture after stent removal.

RESULTS AND LIMITATIONS

A total of 49% of the patients experienced complications. The most frequent were discomfort (23.8%), stress incontinence (17.5%), and stent dislocation (9.8%). Some 85% of the adverse events observed were Clavien-Dindo grade <3. The overall success rate at median FU of 38.2 mo was 76.9%. The success rate was significantly lower if the stent was removed before 6 mo (53.3% vs 79.7%; p = 0.026).

CONCLUSIONS

Temporary urethral stents may be a safe choice with satisfactory results in patients not undergoing urethroplasty. A stent indwelling time shorter than 6 mo provides worse outcomes that are comparable to those with DVIU alone.

PATIENT SUMMARY

We assessed complications and outcomes after placement of a temporary narrow tube in the urethra after surgery to widen a narrowing of the urethra. The treatment is safe and easily reproducible with satisfactory results. Further studies are needed to confirm our findings.

The impact of surgical volume on perioperative safety after urethroplasty: a population-based study

BACKGROUND

The aim of the study was to assess whether the risk of perioperative complications after urethroplasty was affected by hospital annual surgical volume (ASV).

METHODS

In the Nationwide Inpatient Sample, we searched for patients who underwent urethroplasty between 2001 and 2015. Hospitals were categorized into empirically determined tertiles, according to ASV of performed urethroplasties and divided into low (<3) (LVC), intermediate (3-19) (IVC) and high (>20) volume centers (HVC). Multivariable logistic regression (MLR) analyses examined the effect of ASV on perioperative complications and on four specific sub-types of post-operative complications.

RESULTS

A weighted estimate of 39 912 patients underwent urethroplasty in the US. 34.9% were operated in HVC, while the rate of performed urethroplasties increased in LVC and decreased in HVC. Overall, 1.1%, 18.8% and 2.1% patients respectively experienced intraoperative, post-operative, and transfusions complications. At MLR, IVC and LVC were associated with higher risk of both intraoperative (IVC: OR 2.65, P=0.0008; LVC: OR 4.98, P<0.0001), post-operative (IVC: OR 1.14, P=0.01; LVC: OR 1.26, P=0.001) and transfusions complications (IVC: OR 1.85, P<0.001; LVC: OR 3.03, P=0.01). LVC was also associated with higher risk of hematuria (OR 3.77), urinary infections (OR 1.60) and sepsis (OR 2.83) complications.

CONCLUSIONS

Approximately 65% of patients were operated in IVC and LVC, and patients treated in IVC or LVC had higher risk of developing both intra and post-operative complications. These data provide important indicators for policy makers to categorize institution based on urethroplasty outcomes.

The Learning Curve for Radical Nephrectomy for Kidney Cancer: Implications for Surgical Training

Although radical nephrectomy (RN) is the most common treatment for kidney cancer, no data on the learning curve for RN are available. In this study we investigated the effect of surgical experience (EXP) on RN outcomes using data for 1184 patients treated with RN for a cT1-3a cN0 cM0 renal mass. EXP was defined as the total number of RNs performed by each surgeon before the patient's operation. The primary study outcomes were all-cause mortality, clinical progression, Clavien-Dindo grade ≥2 postoperative complications (CD ≥2), and the estimated glomerular filtration rate (eGFR). Secondary outcomes were operative time, estimated blood loss, and length of stay. Multivariable analyses adjusted for case mix revealed no evidence of association between EXP and all-cause mortality (p = 0.7), clinical progression (p = 0.2), CD ≥2 (p = 0.6), or 12-mo eGFR (p = 0.9). Conversely, EXP was associated with shorter operative time (estimate -0.9; p < 0.01). Mortality, cancer control, morbidity, and renal function might not be affected by EXP. The very large cohort examined and the extensive follow-up support the validity of these negative findings.

Patient summary

For patients with kidney cancer undergoing surgical removal of a kidney, those treated by novice surgeons have similar clinical outcomes to those treated by experienced surgeons. Thus, this procedure represents a convenient scenario for surgical training if longer operating theatre time can be planned.

[Bile duct repair after complete intersection]

OBJECTIVE

To determine the training period for imposing hepaticojejunostomy for bile duct repair.

MATERIAL AND METHODS

Reconstructive surgery on the bile ducts was performed in 53 patients. We analyzed the learning curves based on the incidence of anastomotic leakage after hepaticojejunostomy.

RESULTS

The learning curve has a downward nature. The number of anastomotic failures decreases by 2 times after 42 procedures. Surgeon had to perform 39-42 operations to reduce the incidence of this complication.

CONCLUSION

Treatment of patients with iatrogenic intersections of the bile ducts should be provided in appropriate hospitals.

The learning curve of endoscopic endonasal transsphenoidal surgery for pituitary adenomas with different surgical complexity

Objective

To investigate the learning curve under different surgical complexity in endoscopic transsphenoidal approach for pituitary adenoma.

Methods

273 patients undergoing endoscopic transsphenoidal surgery for pituitary adenoma were collected retrospectively and divided into three groups chronologically (early, middle, and late periods). Surgical complexity was differentiated based on Knosp classification (Knsop grade 0-2 vs. Knosp grade 3-4), tumor maximum diameter (MD) (macroadenomas vs. giant adenomas), and history of previous surgery for pituitary adenoma (first operation vs. reoperation). Then the temporal trends in operative time, surgical outcomes, and postoperative complications were evaluated from early to late.

Results

The median operative time decrease from 169 to 147 min across the three periods (P = 0.001). A significant decrease in operative time was seen in the simple groups [Knosp grade 0-2 adenoma (169 to 137 min, P < 0.001), macroadenoma (166 to 140 min, P < 0.001), and first operation (170.5 to 134 min, P < 0.001)] but not in their complex counterparts (P > 0.05). The GTR rate increased from 51.6% to 69.2% (P = 0.04). The surgical period was an independent factor for GTR in the simple groups [Knosp grade 0-2 adenoma: OR 2.076 (95%CI 1.118-3.858, P = 0.021); macroadenoma: OR = 2.090 (95%CI 1.287-3.393, P = 0.003); first operation: OR = 1.809 (95%CI 1.104-2.966, P = 0.019)] but not in the complex groups. The biochemical cure rate increased over periods without statistical significance (from 37.5% to 56.3%, P = 0.181). Although intraoperative CSF leakage rose (from 20.9% to 35.2%) and postoperative CSF leakage reduced (from 12.1% to 5.5%), there was no statistically significant trend across the three time periods (P > 0.05).

Conclusion

This study showed that complex operations might have a prolonged learning curve. Differentiating surgical difficulty and using multivariate combined analysis may be more helpful in clinical practice.

Learning curve of uniportal video-assisted thoracoscopic lobectomy: an analysis of the proficiency of 538 cases from a single centre

OBJECTIVES

Uniportal video-assisted thoracoscopic surgery (UniVATS) is widely used as a minimally invasive thoracic operation. The goal of our study was to analyse the effect of long-term experience with the UniVATS lobectomy on the learning curve.

METHODS

The learning curves were quantitatively evaluated by the unadjusted cumulative sum, and they were segmented using joinpoint linear regression analysis. The variables were compared between subgroups using trend analysis, and linear regression analysis was applied to correlate clinical characteristics at different stages of the learning curve with the duration of the operation.

RESULTS

The learning curve for the UniVATS lobectomy can be divided into 3 phases of proficiency at ∼200-300 procedures, with a fourth phase as the number of procedures increases. The 1st-52nd, 52nd-156th, 156th-244th and 244th-538th procedures comprised the preliminary learning stage, preliminary proficiency stage, proficiency stage and advanced proficiency stage, respectively. Surgical outcomes and their variability between stages improved with increasing case numbers, with the most significant addition of an auxiliary operating port and conversions. In multivariable analysis, as stages progressed, influences other than surgical experience increased the operative time, with male and extensive pleural adhesions in the preliminary proficiency stage; male and incomplete pulmonary fissures in the proficiency stage; and male, extensive pleural adhesions and incomplete pulmonary fissures in the advanced proficiency stage.

CONCLUSIONS

As the number of procedures increases, there may be 4 different proficiency stages in the UniVATS lobectomy learning curve. The surgeon enters the fourth stage at approximately the 244th procedure. Moreover, at stage 4, the perioperative indicators tend to stabilize, and influences other than surgical experience become more significant.

Effect of uncultured adipose-derived stromal vascular fraction on preventing urethral stricture formation in rats

Urethral stricture (US) remains a challenging disease without effective treatment options due to the high recurrence rate. This study aims to evaluate the preventive effect of uncultured adipose derived stromal vascular fraction (SVF) on urethral fibrosis in a rat model of US. Results demonstrated that US rats displayed hyperechogenic urethral wall with a narrowed lumen compared with sham rats, while SVF rats exhibited less extensive urethral changes. By histology, US rats showed obvious submucosal fibrosis in the urethral specimens, while SVF rats exhibited mild submucosal fibrosis with less extensive tissue changes. Furthermore, US rats showed increased gene and protein expression of collagen I (2.0 ± 0.2, 2.2 ± 0.2, all were normalized against GAPDH, including the following), collagen III (2.5 ± 0.3, 1.2 ± 0.1), and TGFβ1R (2.8 ± 0.3, 1.9 ± 0.2), while SVF cells administration contributed to decreased gene and protein expression of collagen I (1.6 ± 0.2, 1.6 ± 0.2), collagen III (1.8 ± 0.4, 0.9 ± 0.1), and TGFβ1R (1.8 ± 0.3, 1.3 ± 0.2), in parallel with the improvement of vascularization and increased expression of VEGF (1.7 ± 0.1) and bFGF (3.1 ± 0.3). Additionally, SVF served anti-inflammatory effect through regulation of inflammatory cytokines and cells, accompanied with conversion of the macrophage phenotype. Our findings suggested that uncultured SVF presented an inhibitory effect on stricture formation at an early stage of urethral fibrosis.

[Urethroplasties for male urethral strictures: Success rates and predictive factors]

INTRODUCTION

Urethroplasty has reported success rates ranging from 60 to 98%. Predictive factors for recurrence are rarely studied, postoperative urinary drainage modalities are not investigated. The primary objective was to evaluate the success rate of urethroplasty in our center. Secondary objectives were to identify recurrence predictive factors.

METHODS

A single-center retrospective cohort including men treated with urethroplasty for stricture between 2007-2017, followed up for a minimum of 12 months. Recurrence was defined as the necessity of a new procedure (endo-urethral or surgical). Data from penile urethra (SUP) and bulbo-membranous urethra (SUBM) stenosis were analyzed separately. Recurrence-free survival (success) was analyzed according to the Kaplan-Meier model. The characteristics of the patients, the stenosis, the surgical technique, the modalities of postoperative urinary drainage were analyzed in subgroups for the bulbo-membranous urethra looking for a correlation with recurrence.

RESULTS

A total of 103 patients included: 25 with SUP, 78 with SUBM. The overall success rate was 69%, CI95% [60-79] with a mean follow-up of 62.85 months. The success was 68%, CI95%[46-82] for SUP, 69.23%, CI95% [58-78] for SUBM. Recurrences occurred during the first 12 months. Only postoperative suprapubic urinary drainage was a predictive factor (HR=0.947, CI95% [0.905-0.992]). A period longer than 14 days reduced recurrence by 37%.

CONCLUSION

Urethroplasty had a success rate of 69%, comparable to published series. Suprapubic urinary drainage improved the surgery outcomes.

LEVEL OF PROOF

2, Grade B.

Periurethral Abscess Following Urethral Reconstruction: Clinical Features and Prognosis

OBJECTIVES

To evaluate the clinical and prognostic details of periurethral abscess (PUA) formation following urethroplasty (UP).

METHODS

A retrospective review was performed to identify men who developed PUA after UP between 2007 and 2019 at a single tertiary care referral center. Patient demographics, stricture characteristics, and UP technique were recorded. Outcomes included time to PUA, presenting symptoms, wound cultures, imaging, and ultimate management. Comparative analysis between PUA and non-PUA patients was performed using Fisher's Exact test and Student's t-test.

RESULTS

Among 1499 UP cases, 9 (0.6%) developed PUA. Mean stricture length was 4.6 cm with most located in the bulbar urethra (5/9, 56%), while 4/9 (44%) had undergone prior UP. PUA rates were 7/288 (2.4%) and 2/815 (0.3%) for substitution and anastomotic UP respectively. Voiding cystourethrogram (VCUG) demonstrated extravasation in 67% (4/6) of available UP cases imaged. Subsequent VCUG confirmed leak improvement or resolution in all cases. Wound cultures were frequently polymicrobial (4/6, 67%). Management included antibiotics with (6/9) and without (3/9) incision and drainage (I/D). Urinary drainage was performed in 5 patients using suprapubic tube (3/5) and foley placement (2/5). PUA resolution was observed in all patients while stricture symptom recurrence was observed in 2/9 (22%) patients with mean time to recurrence of 15 months. Overall mean follow-up time was 22 months.

CONCLUSION

PUA is a rare complication of UP that may be more common in setting of postoperative urine leak. PUA is safely managed with I/D, urethral rest, and antibiotics, with low risk of recurrent stricture formation thereafter.

Comparison of two different methods of establishment of canine urethroplasty model: an experimental trial

Background

Graft substitute urethroplasty is recommended for patients with long segment anterior urethral stricture. The therapeutic effects of the grafts need to be validated on the animal models. Therefore the aim of this study was to compared the operative time, blood loss, intra- and post- operative complications of two different methods of establishment of canine urethroplasty model.

Methods

Twelve Beagle dogs were randomly separated into control and experimental group using a random number table. Six animals in the control group received the conventional urethroplasty, while the other 6 in the experimental group received the modified procedures. Tube cystostomy and urethroplasty were performed in the control group. The cystostomy not the tube cystostomy were performed in the experimental group, and the testes were simultaneously removed with the scrotum. Per- and postoperative outcomes, complications were evaluated.

Results

The urethroplasty were successfully performed for all dogs and all of these procedures were done by the same surgeon. The median operative time in the control and experimental groups was 186.8 min and 188.7 min respectively. The blood loss in the control and experimental groups was 40.8 ml and 45.8 ml respectively. No intraoperative complications occurred. 3 animals in the control group developed acute urinary retention after the accidental removal of suprapubic bladder tube and the cystostomy was done again. There was no occurrence of urinary retention in the experimental group. 4 animals in the control group developed the perineal hematoma, in which one animal had the urine leakage and incision infection. Perineal hematoma occurred in only one animal in the experimental group.

Conclusion

The occurrence of urinary retention and perineal hematoma decreased in the modified group, in which the cystostomy not the tube cystostomy were performed and the testes with the scrotum were simultaneously removed.

[Management of urethral stricture]

Urethral strictures most frequently affect the bulbar but are also observed in the penile, glandular, or membranous urethra. They are often iatrogenic. Radiologic diagnosis can be established easily and safely by cystourethrography. Simple Sachse urethrotomy can result in permanent relief in the case of short bulbar strictures in initial findings. Recurrent structures or strictures in other locations should however be treated by open surgery, as cure cannot be achieved by other means. Depending on the diagnosis and comorbidities, end-to-end anastomosis, graft/flap urethroplasty, or perineal urethrostomy can be performed. If open surgery is delayed, aggravation of the diagnosis and worsening of the prognosis can be expected, regardless of the applied treatment.

Uretroplastia bulbar con injerto: Una actualización sobre las diferentes técnicas quirúrgicas

En pacientes con estrechez uretral bulbar de una longitud mayor a 2 cm, que no sean candidatos a otras técnicas, se realiza uretroplastia con injerto. Actualmente se emplean diversas técnicas, cada una con ventajas y desventajas propias.

Describir las ventajas y desventajas de las técnicas quirúrgicas empleadas actualmente en la uretroplastia con injerto, así como sus tasas de éxito.

Se hizo una búsqueda en PubMed, ClinicalKey y en ScienceDirect, utilizando las palabras claves: “urethral stricture,” “urethroplasty,” “oral graft” y “flap.” Se utilizaron los estudios más relevantes, tanto originales como revisiones sistemáticas y meta-análisis, en inglés y en español.

Las diferentes técnicas quirúrgicas ofrecen ventajas y desventajas teóricas frente a las otras, aunque las tasas de éxito en todas es cercana al 90%, sin ser una francamente superior frente a las demás.

La elección de la técnica quirúrgica a realizar depende de las preferencias y experiencia del cirujano, dado que la tasa de éxito para todas las técnicas es similar.

Cell-Seeded Acellular Artery for Reconstruction of Long Urethral Defects in a Canine Model

The management of urethral stricture remains a major therapeutic challenge in clinics. Herein, we explored the feasibility of reconstructing a relatively long segment of the urethra by the cell-seeded acellular artery in a canine model. The acellular arterial matrix was obtained from the excised carotid artery of donor dogs. Autologous adipose-derived stem cells (ADSCs) from 6 male dogs were grown and seeded onto the premade acellular arterial matrix. A 3 cm long segment of the urethra was resected in 12 male dogs. Urethroplasty was performed with the acellular arterial matrix seeded with ADSCs in 6 animals and without cells in 6. Serial urethrography was performed at 1 and 3 months postoperatively. Wide urethral calibers without any signs of strictures were confirmed in all 6 animals in the experimental group. In contrast, urethral stricture was demonstrated in 3 animals in the control group. The graft was highly epithelialized and smooth in the experimental group, while graft contracture and scar formation were showed in the control group. Histologic analysis of the cell-seeded arterial matrix at 1 month confirmed the presence of multilayered urothelium and muscle. The levels of tissue formation developed over time with a progressive increase in muscle content. In contrast, extensive fibrosis and sparse smooth muscle were seen in animals treated with matrix without ADSCs. This study provides preclinical evidence that the ADSC-seeded arterial matrix can be used as a tubularized scaffold in the reconstruction of 3 cm long urethral defect in a male canine model. The ADSC-seeded arterial matrix remodels and regenerates normal-appearing urethral tissue layers over time.

Long term outcomes of one-stage augmentation anterior urethroplasty: a systematic review and meta-analysis

OBJECTIVE

The objective is to summarize and characterize the long-term success of anterior augmentation urethroplasty (AU) in published series. The current literature on AU consists largely of retrospective series reporting intermediate follow-up and incompletely characterize the long term outcomes of AU.

MATERIALS AND METHODS

A systematic literature review was performed consistent with PRISMA guidelines to characterize long-term outcomes of AU with a minimum upper limit follow-up of 100 months. Penile/preputial skin flaps and graft and oral mucosal graft urethroplasties were included. The primary outcome was stricture-free survival for one-stage AU. Secondary analysis evaluated differences in outcomes based on two failure definitions: the need for intervention versus presence of recurrent stricture on cystoscopy or urethrography. Hazard rates were induced from the reported failure rates of one-stage AU and fixed and random effect models were fitted to the data. Additional subset analysis, removing potential confounders (lichen sclerosus, hypospadias and penile skin graft), was performed.

RESULTS

Ten studies met inclusion criteria, and two studies reported separate outcomes for grafts and flaps, and thus were included separately in the analysis. The mean hazard rate across all studies was 0.0044, the corresponding survival rates at 1 year 0.948, 5 years 0.766, 10 years 0.587, and 15 years 0.45. Subset analysis of the 4 select and homogeneous studies noted 1, 5, 10, and 15 years survival rates of 0.97, 0.96, 0.74, and 0.63, respectively.

CONCLUSIONS

The long-term success rates of augmentation urethroplasty are appear to be worse than previously appreciated and patients should be counseled accordingly. Available at. https://www.intbrazjurol.com.br/pdf/aop/2019-0242RW.pdf.

The preventative effect of bone marrow-derived mesenchymal stem cell exosomes on urethral stricture in rats

Background

Urethral stricture (US) is a major challenge in urology and there is an urgent need for effective therapies for its treatment. Exosomes derived from bone marrow mesenchymal stem cells (BMSCs-Exos) have been shown to be effective in preventing scar and fibrosis formation after tissue injury. However, the potential utility of BMSCs-Exos in the prevention of US remains unknown. We hypothesized that local administration of BMSCs-Exos may influence urethral healing and scar formation in a rat model of US.

Methods

A previously established model of rat US was used in this study. Sprague Dawley rats were randomly assigned into sham, US, and US + BMSCs-Exos groups. Micro-ultrasound assessment, histopathology, immunohistochemistry, and gene expression analysis were performed at four weeks post-surgery.

Results

US rats exhibited thick urethral walls with a narrowed lumen, when compared with sham rats. However, these changes were suppressed in the US + BMSCs-Exos group. The preventative effects of BMSCs-Exos on US formation were also apparent histologically. US + BMSCs-Exos rats demonstrated decreased expression of several fibrosis-related genes in urethral tissues, including Col I, fibronectin, and elastin, when compared with US rats. BMSCs-Exos treatment also led to an increase in the expression of angiogenesis-related genes in these tissues, including VEGF, eNOS, and bFGF.

Conclusions

Our findings therefore demonstrate that the local administration of BMSCs-Exos prevents urethral stricture formation by regulating fibrosis and angiogenesis. These findings provide a basis for an innovative strategy involving the clinical application of exosomes to counteract US formation.

Development and content validation of the Urethroplasty Training and Assessment Tool (UTAT) for dorsal onlay buccal mucosa graft urethroplasty

OBJECTIVES

To develop and validate the Urethroplasty Training and Assessment Tool (UTAT) using Healthcare Failure Mode and Effect Analysis (HFMEA) for training and assessment of urology trainees learning this urethral reconstruction technique, as urethroplasty is the 'gold standard' treatment for long and recurrent urethral strictures and with a variety of techniques and a lack of standardised reconstructive curricula, there is a need for procedure-specific training tools to improve surgeon training and patient safety.

MATERIALS AND METHODS

This international observational study was performed over an 11-month period. The HFMEA was used to identify and evaluate hazardous stages of urethroplasty to develop the UTAT. Hazard scores were calculated for the included steps of urethroplasty. Content validation was performed by 12 expert surgeons and multidisciplinary teams from international tertiary centres.

RESULTS

The HFMEA process resulted in an internationally validated UTAT. Hazard scores ≥4 and single point weaknesses were included to implement actions and outcome measures. Content validation was achieved by circulating the process map, hazard analysis table, and developed tools. Changes were implemented based on the feedback received from expert surgeons. The content validated dorsal onlay buccal mucosa graft bulbar UTAT contained five phases, 10 processes and 23 sub-processes.

CONCLUSIONS

The modular UTAT offers a comprehensive validated training tool developed via a detailed HFMEA protocol. This may be utilised to standardise the training and assessment of urology trainees.

[Learning curves in acquisition of experience for new technologies]

OBJECTIVE

Analysis of national and foreign trials investigating accumulation of experience in innovative technologies using the learning curves.

MATERIAL AND METHODS. S

Earching for Russian-language manuscripts was carried out within the references of the articles and in the ELIBRARY database. Foreign trials were selected from the PubMed database according to the keywords «learning curves in surgical practice». The discovered publications were studied for accordance with the objectives of this study.

RESULTS

Accumulation of experience in new technologies by using of learning curves is valuable to improve the training, determine duration of development of new technology and the factors affecting its characteristics.

CONCLUSION

The method is high-quality for comprehensive analysis of experience accumulation in new surgical technologies.

Learning curve of various type of male urethroplasty

Purpose

To determine the number of cases required to achieve a specified recurrence-free rate (>80%) among urethroplasty types.

Materials and Methods

A retrospective analysis of consecutive patients, who underwent urethroplasty performed by a single surgeon between April 2013 and January 2019, was conducted. Urethroplasty subtypes were divided according to stricture location: penile, bulbar, and posterior. If there was no recurrence for >6 months after surgery, the surgery was considered to be a success. The average success rates among quintile groups were compared to determine the learning curve for each type.

Results

Of 150 patients who underwent urethroplasty, 112 were included in this study. The overall success rate was 89.7% in penile, 97.8% in bulbar, and 74.1% in posterior urethroplasty. Bulbar urethroplasty reached the target success rate in the first quintile group (1–9 cases). Penile urethroplasty also achieved the target success rate in the first quintile group (1–8 cases), and the success rate gradually increased until the fifth quintile group (32–39 cases). In posterior urethroplasty, the target success rate was achieved in the fifth quintile group (20–27 cases).

Conclusions

Bulbar urethroplasty had the fastest learning curve, and posterior urethroplasty the slowest.

Canadian Urological Association guideline on male urethral stricture

Urethral stricture is fundamentally a fibrosis of the urethral epithelial and associated corpus spongiosum, which in turn, causes obstruction of the urethral lumen. Patients with urethral stricture most commonly present with lower urinary tract symptoms, urinary retention or urinary tract infection but may also experience a broad spectrum of other signs and symptoms, including genitourinary pain, hematuria, abscess, ejaculatory dysfunction, or renal failure. When urethral stricture is initially suspected based on clinical assessment, cystoscopy is suggested as the modality that most accurately establishes the diagnosis. This recommendation is based on several factors, including the accuracy of cystoscopy, as well as its wide availability, lesser overall cost, and comfort of urologists with this technique. When recurrent urethral stricture is suspected, we suggest performing retrograde urethrography to further stage the length and location of the stricture or referring the patient to a physician with expertise in reconstructive urology. Ultimately, the treatment decision depends on several factors, including the type and acuity of patient symptoms, the presence of complications, prior interventions, and the overall impact of the urethral stricture on the patient's quality of life. Endoscopic treatment, either as dilation or internal urethrotomy, is suggested rather than urethroplasty for the initial treatment of urethral stricture. This recommendation applies to men with undifferentiated urethral stricture and does not apply to trauma-related urethral injuries, penile urethral strictures (hypospadias, lichen sclerosus), or suspected urethral malignancy. In the setting of recurrent urethral stricture, urethroplasty is suggested rather than repeat endoscopic management but this may vary depending on patient preference and impact of the symptoms on the patient.The purpose of this guideline is to provide a practical summary outlining the diagnosis and treatment of urethral stricture in the Canadian setting.

Dorsal oral mucosa graft in combination with ventral penile flap as an alternative to repair obliterative stenosis of the anterior urethra in a single surgical time

Purpose:

Obliterative urethral stenosis is a type of urethral lesion that compromises the whole corpus spongiosum's circumference. We present our experience in resolving complex long segment urethral obliteration in a single procedure using a combination of dorsal onlay oral mucosa graft (OMG) and ventral fasciocutaneous penile skin flap.

Materials and methods:

A prospectively maintained database was reviewed, which included data of men presenting long, obliterative strictures. Patients were excluded if they were lost to follow-up before one year. Failure was defined as need for further urethral instrumentation.

The surgical technique used consisted on the fixation of OMG to the tunica albuginea of the corpus cavernosum, thus creating a new urethral plate. Penile or foreskin flaps were employed to complete the ventral aspect. Postoperative follow-up was done with a voiding cystourethrography at week 3.

Results:

A total of 21 patients were included with a median age of 49 years. Mean follow-up was 25 months. Failure was found for 3 patients (2 of them needing dilations and only one required a new urethral reconstruction).

Conclusion:

Single stage combination of dorsal OMG with ventral fasciocutaneous penile flap showed good results for selected patients affected with obliterative urethral stenosis.

Transurethral ventral buccal mucosa graft inlay for treatment of distal urethral strictures: international multi-institutional experience

PURPOSE

To critically evaluate a multi-institutional patient cohort undergoing single-stage distal urethral repair using a novel transurethral buccal mucosa graft inlay urethroplasty technique (TBMGI).

METHODS

A retrospective multi-institutional review of consecutive patients with fossa navicularis (FN) strictures treated with a single-stage TBMGI technique at 12 institutions from March 2014-March 2018 was performed. Patient demographics, stricture characteristics, clinical and patient-reported outcomes were analyzed. The primary outcomes were stricture recurrence and complications. Secondary outcomes were change in maximum urinary flow rate (Qmax), PVR, and changes in IPSS, SHIM and global response assessment (GRA) questionnaire responses. Descriptive statistical analysis was used for evaluation of outcomes.

RESULTS

Sixty-eight men met inclusion criteria. Median age and stricture length were 60 years (IQR 48-69) and 2 cm (IQR 2-3), respectively. Most common stricture etiology was lichen sclerosus (34%). Median operative time and EBL were 72 min (IQR 50-120) and 20 mL (IQR 10-43), respectively. Fifty-seven men completed ≥ 12-month follow-up. At a median follow-up of 17 months (IQR 13-22), 54 patients (95%) remained stricture-free. Median Qmax improved from 5 to 18 mL/s (p < 0.0001), PVR 76-21 mL (p < 0.0001), and IPSS 15-5 (p < 0.0001); IPSS-QOL score: 5-1 (p < 0.0001). SHIM score did not significantly change following repair (median 22-21 p = 0.85). On GRA assessment, a majority of men reported "marked" (64%) or "moderate" (28%) overall improvement. No patient developed fistula, glanular dehiscence, graft necrosis or chordee.

CONCLUSIONS

This novel minimally invasive transurethral urethroplasty technique is feasible and has demonstrated generalizable outcomes in a multi-institutional cohort with varying etiologies.

Stretchable collagen-coated polyurethane-urea hydrogel seeded with bladder smooth muscle cells for urethral defect repair in a rabbit model

The major challenge to treat the clinical adverse effects of long-segment urethra is in achieving viable tissue substitution. The substituted construct's properties-such as its resilience, contraction, and ability to minimize scar-stenosis formation should be considered. In the present work, a unique polyurethane-urea (PUU) fibrous membrane is fabricated by electrospinning. Then PUU was coated by collagen and formed the elasticity hydrogel after immersed in collagen solution. Meanwhile, the cPUU hydrogel exhibited a fibrous microstructure. This cPUU hydrogel had outstanding stretching property with 404 ± 40% elongation at break compared with traditional hydrogels, which satisfied the requirement of urethra. The cPUU hydrogel also supported the adhesion and growth of bladder smooth-muscle cells (BSMCs) in natural state cell morphology. Urethral defects in New Zealand male rabbits were repaired with cPUU seeded with BSMCs in vivo. After three months, more smooth-surface area of reconstructed urethral tissues was observed in the cPUU hydrogel-BMSCs groups compared with that of the control group. The luminal patency and the incidence of complications-including calculus formation, urinary fistula, and urethral-stricture occurrence were significantly lower in the cPUU group compared with that of the control group. Hence, cPUU fibrous hydrogels are promising scaffolds for application in urological tissue engineering.

[Bulbar urethral strictures : A trivial urological disease or a surgical challenge?]

Urethral strictures are often located in the bulbar urethra, and bulbar strictures are commonly due to urethral trauma. Diagnosis is confirmed by radiographic imaging of the urethra. In cases of short primary bulbar strictures, a simple internal urethrotomy may be curative. In contrast, open surgery should be performed in long segment or recurrent strictures because recurrence rates are near 100% in these cases. Depending of the actual findings and comorbidities, end-to-end anastomosis, graft urethroplasty, flap urethroplasty, or perineal urethrostomy may be used. If definitive treatment using open surgery is delayed and multiple endoscopic treatments are tried, urethroplasty becomes more complex and success rates of definitive treatment decline.

TNF-α-induced exosomal miR-146a mediates mesenchymal stem cell-dependent suppression of urethral stricture

The effective treatment of urethral stricture remains a medical problem. The use of proinflammatory cytokines as stimuli to improve the reparative efficacy of mesenchymal stem cells (MSCs) towards damaged tissues represents an evolving field of investigation. However, the therapeutic benefits of this strategy in the treatment of urethral stricture remain unknown. Here, we enriched exosomes derived from human umbilical cord-derived MSCs pretreated with or without tumor necrosis factor alpha (TNF-α) to evaluate their therapeutic effects in an in vivo model of TGFβ1-induced urethral stricture. Male Sprague-Dawley rats received sham (saline) or TGFβ1 injections to urethral tissues followed by incisions in the urethra. Animals in the TGFβ1 injection (urethral fibrosis) cohort were subsequently injected with vehicle control, or with exosomes derived from MSCs cultured with or without TNF-α. After 4 weeks, rats underwent ultrasound evaluation and, following euthanasia, urethral tissues were harvested for histological and molecular analysis. In vitro, the effects of MSC-derived exosomes on fibroblast secretion of collagen and cytokines were studied by enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and western blot analysis. Exosomes derived from MSCs pretreated with TNF-α were more effective in suppressing urethral fibrosis and stricture than exosomes from untreated MSCs. We found that miR-146a, an anti-inflammatory miRNA, was strongly upregulated in TNF-α-stimulated MSCs and was selectively packaged into exosomes. Moreover, miR-146a-containing exosomes were taken up by fibroblasts and inhibited fibroblast activation and associated inflammatory responses, a finding that may underlie the therapeutic mechanism for suppression of urethral stricture. Inhibition of miR-146a in TNF-α-treated MSCs partially reduced antifibrotic effects and increased the release of proinflammatory factors of exosomes derived from these cells. Together these findings demonstrate that exosomes derived from TNF-α-treated MSCs are of therapeutic benefit in urethral fibrosis, suggesting that this strategy may have utility as an adjuvant therapy in the treatment of urethral stricture diseases.

The outcomes of Kulkarni's one-stage oral mucosa graft urethroplasty in patients with panurethral stricture: a single centre experience

PURPOSE

To present the results of our one-stage oral mucosa graft urethroplasty series for panurethral strictures.

METHODS

We included the first 35 patients who had one stage oral mucosa graft urethroplasty with one side dissection of the urethra which was described by Kulkarni, between January 2015 and June 2018 and had at least 6 months follow-up. From the first case, all data were recorded prospectively and patient age, etiology of the stricture, comorbidities, previous treatments, postoperative maximal flow rate, pre and post-operative erectile function, perioperative and postoperative complications and quality of life questionnaire for this study.

RESULTS

The mean patient age was 58.8 and mean stricture length was 13.6 (10-16) cm. Patients had previously 1-17 procedures. Patients had a mean peak flow rate of 25.4 ml/sec at the first postoperative visit. During the follow-up period, six patients had recurrence and managed with urethral dilation (1), direct vision internal urethrotomy (2), meatoplasty (1) and re-urethroplasty (2). The responses to the questions about satisfaction from the surgery showed that 31 (88.6%) patients were satisfied with the surgery, 33 (94.3%) would prefer this procedure again, if needed, and 31 (88.6%) patients recommended this procedure to others. When patients were grouped according to age, recurrence rate was 35.7% in patients older than 65 years and 4.8% in patients ≤ 65 years old.

CONCLUSIONS

Our study showed that Kulkarni's one-stage oral mucosa graft urethroplasty technique has a high success rate. The patient satisfaction is high because of the good functional outcomes and low complication rate.

Population Analysis of Male Urethral Stricture Management and Urethroplasty Success in the United States

OBJECTIVE

To examine population-based practice patterns and outcomes related to urethroplasty for urethral stricture management.

METHODS

We conducted a retrospective study of adult males with urethral stricture disease treated from January 2001 to June 2015 using the Clinformatics Data Mart Database. Treatment was defined as urethral dilation, direct visualized internal urethrotomy, and urethroplasty. We then examined anterior or posterior urethroplasty outcomes defining failure as any subsequent procedure specific to urethral stricture disease occurring >30 days after urethroplasty. We used multivariable and time-to-event analysis to examine factors associated with failure.

RESULTS

We identified 75,666 patients treated for urethral stricture disease, with 420 and 367 undergoing anterior and posterior urethroplasty, respectively. Urethroplasty utilization doubled from 2005 to 2015. One- and 5-year failure rates for anterior and posterior urethroplasty were 25% and 18%, and 40% and 25%, respectively, with median times to failure of 5.1 and 4.1 months. Failures were salvaged primarily with direct visualized internal urethrotomy, with salvage urethroplasty in 19% and 12% of anterior and posterior repairs, respectively.

CONCLUSION

Despite increasing population-based urethroplasty utilization over the past decade in our insured cohort, we found higher rates of salvage treatments than reported by high-volume and expert surgeon reports. Further efforts appear warranted to balance workforce expertise and quality of urethroplasty care to meet increasing urethral stricture population needs.

International volunteerism and urethral stricture disease: a review

Global health is an ever-expanding area of interest for many healthcare workers around the world. In recent years, it has become apparent that much of the global disease burden is surgical. Urologic disease is no exception—many international organizations send volunteers around the world to support Urologic services in countries that lack capacity and resources. Urethral stricture represents a unique opportunity for specialized surgical management that vastly improves long term morbidity. Here we review the prevalence, etiology, and management of urethral stricture from a global perspective while highlighting impact of international urologic volunteer efforts.

Describing the learning curve for bulbar urethroplasty

Background

Learning curves have been described for a number of urological procedures including radical prostatectomy and laparoscopic nephrectomy but rarely for urethroplasty. We describe the learning curve for bulbar urethroplasty in a single surgeon series.

Methods

A retrospective case note review was performed of 91 consecutive men median age 32 years (range, 15–66 years) having bulbar urethroplasty performed by a single surgeon. Data was collected on type of urethroplasty, restricture rate (as defined by urethrogram and/or flow rate) and duration of follow up. The restricture rates were compared by quartiles and statistical analysis was by ¦Ö² between the first and fourth quartiles.

Results

The 91 men had 42 dorsal onlay buccal mucosal graft (Dorsal BMG), 20 BMG augmented bulbobulbar anastomotic (Augmented Rooftop) and 29 bulbobulbar anastomotic (BBA) urethroplasties performed. Median follow up was 39 months for the first quartile, 42 months for the second, 36 months for the third, and 35 months for the fourth. The restricture rate was 17% in the first quartile, 8.7% in the second and third quartiles and 4.5% in the fourth quartile. There were no restrictures noted after 24 months. There were 4 restrictures in the first quartile and 1 restricture in the fourth quartile (¦Ö² P<0.01).

Conclusions

There is a statistically and clinically significant difference in restricture rates between first and fourth quartiles with rates falling from 17% to 4.5%. There is a learning curve for bulbar urethroplasty with a reduced restricture rate each quartile and it may take as many as 90 cases to reach optimum restricture rates.

Clinical and Patient-reported Outcomes of 1-sided Anterior Urethroplasty for Long-segment or Panurethral Strictures

OBJECTIVE

To evaluate clinical and patient-reported urinary and sexual outcomes after a long-segment stricture repair using the 1-sided urethral dissection, penile invagination, and dorsal buccal mucosa graft onlay technique described by Kulkarni et al.

METHODS

Patients from 4 institutions after single-stage repairs for long-segment urethral strictures (>8 cm) from January 2002 to April 2016 were reviewed. Technique described by Kulkarni et al was used in all cases. Clinical outcomes included uroflowmetry (Qmax) and post-void residuals. Patient-reported outcome measures included International Prostate Symptom Score survey, Sexual Health Inventory for Men, Male Sexual Health Questionnaire, and Global Response Assessment questionnaire to measure voiding, sexual, ejaculatory symptoms, and overall improvement, respectively.

RESULTS

Seventy-three patients with a minimum of 12 months' follow-up were included. The mean age and stricture length were 56 (21-80) years and 13.6 (8-21) cm, respectively. At a mean follow-up of 44 (12-162) months, 9 of 73 (12%) strictures recurred. The mean baseline International Prostate Symptom Score of 23 (7-24) decreased to 10 (1-17) on follow-up (P <.001). Eight of 42 patients (21.4%) reported an increase, and 6 of 42 patients (14.3%) decreased in Sexual Health Inventory for Men following urethroplasty. Ejaculatory function on Male Sexual Health Questionnaire improved after urethroplasty from 8 preoperatively to 11 postoperatively (P <.004). All patients reported improvement after urethroplasty on Global Response Assessment questionnaire. Post-void dribbling and chordee occurred in 45% and 25% of patients, respectively.

CONCLUSION

Durable patency in most patients is demonstrated in this study. PROMs indicate an improvement in urinary function and moderate effect on sexual function. Transient penile chordee was evident in 25% of patients.

Learning Curve and Clinical Outcomes of Performing Surgery with the InterTan Intramedullary Nail in Treating Femoral Intertrochanteric Fractures

Purpose. The purpose of this study is to evaluate the learning curve of performing surgery with the InterTan intramedullary nail in treating femoral intertrochanteric fractures, to provide valuable information and experience for surgeons who decide to learn a new procedure. Methods. We retrospectively analyzed data from 53 patients who underwent surgery using an InterTan intramedullary nail at our hospital between July 2012 and September 2015. The negative exponential curve-fit regression analysis was used to evaluate the learning curve. According to 90% learning milestone, patients were divided into two group, and the outcomes were compared. Results. The mean operative time was 69.28 (95% CI 64.57 to 74.00) minutes; with the accumulation of surgical experience, the operation time was gradually decreased. 90% of the potential improvement was expected after 18 cases. In terms of operative time, intraoperative blood loss, hospital stay, and Harris hip score significant differences were found between two groups (p = 0.009, p = 0.000, p = 0.030, and p = 0.002, resp.). Partial weight bearing time, fracture union time, tip apex distance, and the number of blood transfusions and complications were similar between two groups (p > 0.5). Conclusion. This study demonstrated that the learning curve of performing surgery with the InterTan intramedullary nail is acceptable and 90% of the expert's proficiency level is achieved at around 18 cases.

Improving Outcomes of Bulbomembranous Urethroplasty for Radiation-induced Urethral Strictures in Post-Urolume Era

OBJECTIVE

To evaluate contemporary outcomes of excision and primary anastomosis (EPA) for the treatment of radiation-induced urethral strictures (RUS).

PATIENTS AND METHODS

A retrospective review of 72 patients undergoing EPA for RUS from 2007 to 2015 by a single surgeon was performed. We analyzed overall and long-term success rates of EPA urethroplasty and compared patient cohorts from two groups, 2007-2012 vs 2013-2015 (post-Urolume).

RESULTS

During the course of the study, we noted a near doubling of patient volume from the earlier (6.2 patients/year) to later (11.7 patients/year) cohorts. Among the 37 men treated from 2007 to 2012, we identified an EPA success rate of 70% compared with the improved 86% success rate in the subsequent cohort of 35 men treated from 2013 to 2015 (P = .07). Single dilation was successful in 50% of initial and 40% of subsequent cohort patients in the treatment of recurrence. Initial and subsequent cohorts varied only in regard to stricture length (mean 2.0 cm vs 3.0 cm in initial and subsequent cohorts, P = .001) and number treated with Urolume stent (initial 5 vs none in the later cohort, P = .03). Length of follow-up (median 50 [17-97] months for the initial and 22 [6-34] months for the later cohort) was not associated with recurrence.

CONCLUSION

Increasing numbers of RUS patients are presenting for urethral reconstruction in the post-Urolume era. With increasing experience, we improved success rates of EPA urethroplasty to over 85% despite increased stricture length.

Nontransecting Anastomotic Repair in Urethral Reconstruction: Surgical and Functional Outcomes

PURPOSE

We evaluated the surgical and functional outcomes, and the effect of the learning curve of nontransecting anastomotic repair for short bulbar and posterior urethral strictures.

MATERIALS AND METHODS

A total of 75 patients were treated with nontransecting anastomotic repair for short bulbar strictures in 55 and for posterior strictures in 20. Surgical morbidity was scored using the Clavien-Dindo classification at 3 months. Sexual function was measured using SHIM (Sexual Health Inventory for Men) scoring preoperatively and postoperatively. Post-void dribbling before and after nontransecting anastomotic repair was also determined. To evaluate the learning curve outcomes were evaluated in patients 1 to 25, 26 to 50 and 51 to 75.

RESULTS

Median followup was 30 months. Stricture recurred in 6 patients (8%), all diagnosed within 7 months after nontransecting anastomotic repair. Median operative time was 95 minutes and median hospital stay was 2 days. In 61 patients (81.3%) no surgical morbidity was recorded. Five (6.7%), 6 (8%) and 3 patients (4%) experienced a grade 1, 2 and 3b complication, respectively. Seven of 32 (21.9%) and 2 of 42 evaluable patients (4.7%) reported de novo erectile dysfunction and post-void dribbling, respectively, 3 months after nontransecting anastomotic repair. No difference in outcomes was observed among the 3 patient groups.

CONCLUSIONS

Nontransecting anastomotic repair appears to be safe without a substantial learning curve effect. Patient counseling about possible surgical complications and transient erectile dysfunction is important.

Adipose-derived Stem Cells Counteract Urethral Stricture Formation in Rats

BACKGROUND

A medical treatment for urethral stricture (US) is not yet available.

OBJECTIVE

To evaluate if local injection of human adipose tissue-derived stem cells (hADSC) prevents urethral fibrosis in a rat model of US.

DESIGN, SETTING, AND PARTICIPANTS

Male rats were divided into three groups: sham, US, and hADSC (n=12 each). Sham rats received a vehicle injection in the urethral wall. US and hADSCs were incised and injected with the fibrosis-inducer transforming growth factor-β1 in the urethral wall.

INTERVENTION

One day later, hADSCs were injected in the urethral wall of hADSC rats whereas sham and US rats were injected with the vehicle. After 4 wk, the rats underwent cystometries and tissues were then harvested for functional and molecular analyses.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Cystometry, microultrasound, histochemistry, organ bath studies, reverse transcription polymerase chain reaction, and western blot.

RESULTS AND LIMITATIONS

US rats exhibited 49-51% shorter micturition intervals, 35-51% smaller micturition volumes and bladder capacity, 33-62% higher threshold pressures and flow pressures, and 35-37% lower bladder filling compliance compared with hADSC-treated rats and sham rats (p<0.05). By ultrasound, US rats had hyperechogenic and thick urethral walls with narrowed lumen compared with sham rats, whereas hADSC rats displayed less extensive urethral changes. Isolated detrusor from US rats exhibited 34-55% smaller contractions than detrusor from sham rats (p<0.05). Corresponding values were 11-35% for isolated detrusors from hADSC rats. Collagen and elastin protein expression were increased in the penile urethras of US rats compared with sham and hADSC groups (p<0.05). Endothelial and inducible nitric oxide synthase expressions were higher (p<0.05) in the hADSC group. Compared with US rats, hADSC rats demonstrated decreased expression of several fibrosis-related genes. Administration of hADSCs was performed at an early stage of US development, which we consider a limitation of the study.

CONCLUSIONS

Local injection of hADSCs prevents stricture formation and urodynamic complications in a new rat model for US.

PATIENT SUMMARY

Stem cell therapy is effective for preventing urethral stricture in an experimental setting.

Single-Staged Improved Tubularized Preputial/Penile Skin Flap Urethroplasty for Obliterated Anterior Urethral Stricture: Long-Term Results

INTRODUCTION

To present an improved tubularized flap (ITF) technique and report the outcome of single-stage urethroplasty using preputial/penile skin flaps (PSFs) for the treatment of obliterative anterior urethral strictures (AUSs).

MATERIALS AND METHODS

From January 2000 to June 2012, 42 cases of obliterative AUS (3-14 cm, mean 6.38 cm) with urethral plate unsalvageable were treated using PSF-ITF urethroplasty including longitudinal skin flap, circular island flap, L-flap, Q-flap. Patients were divided into 3 groups: pendulous urethral stricture (Group A), bulbar urethral stricture (Group B) and panurethral strictures (Group C). Patients were followed up by uroflowmetry, urethrography and ureteroscope when necessary.

RESULTS

The mean follow-up in these patients was 65 months (range 36 months-15 years). The primary success rates at 3-year follow-up were 75, 75 and 60% for Groups A, B and C, respectively. The overall success rates were 85, 83 and 70% with the remedial measure of a single visual internal urethrotomy at 3-year follow-up. A total 60% of the patients in the study completed more than 5 years of follow-up with no additional recurrence.

CONCLUSIONS

Improved tubularized preputial/PSF urethroplasty with relatively high overall satisfaction is a novel technique for treatment of AUS when there is inadequate urethral plate or obliterative defects.