Long-term followup of bladder mucosa graft for male urethral reconstruction

Buccal mucosal graft urethroplasty in five male dogs with penile urethral stricture at the bulbus glandis

OBJECTIVES

To evaluate the feasibility of correcting penile urethral strictures at the bulbus glandis using buccal mucosal graft (BMG) urethroplasty in dogs.

STUDY DESIGN

Prospective clinical trial.

ANIMALS

Five male dogs with urethral strictures located at the bulbus glandis.

METHODS

Urethrotomy was performed throughout the entire length of the urethral stricture including ~0.5 cm healthy urethra proximal and distal. The scarred tissue and unhealthy mucosa of the strictured urethra were completely excised. The graft was harvested from the buccal mucosa and tubularized at the stricture site using a urethral catheter as the skeleton. The catheter was maintained for 14 days after surgery and removed when no urethral leakage was identified on a positive-contrast retrograde urethrogram. The dogs were discharged after spontaneous urination was confirmed. Six months postoperative follow-up was completed for all dogs with repeated positive contrast urethrogram and an owner questionnaire to score urinary function and quality of life.

RESULTS

The five dogs recovered well following surgery and only one dog experienced a minor complication. All dogs were able to urinate normally after catheter removal. No evidence of leakage was identified on a 14 day postoperative retrograde positive contrast urethrogram and clinically at a median follow-up time of 182 days (range, 182-186). All owners scored the urinary function as excellent and ranked their satisfaction very high 6 months after the procedure.

CONCLUSION

Buccal mucosal graft urethroplasty has positive outcomes for dogs with penile urethral strictures.

Preliminary results of a new surgical technique: bladder mucosal graft harvested with holmium:YAG (HO:YAG) laser. A new option in bulbar replacement urethroplasty?

OBJECTIVE

To describe the technique of transurethral harvesting of bladder mucosal graft using the Holmium:YAG (Ho-YAG) laser and describe the preliminary results from 7 cases where this graft was used for urethroplasty.

MATERIALS AND METHODS

We performed a single-stage dorsal onlay urethroplasty using bladder mucosal graft in 7 patients with anterior urethral stricture. Transurethral harvesting was performed with the Ho-YAG laser. We performed a prospective and descriptive analysis with uroflowmetry performed at 30, 90 and 180 days after surgery and applied the PROM translated into Portuguese before and 6 months after urethroplasty.

RESULTS

Seven patients were included, 2 (28.5%) with penile urethral stricture, and 5 (71.5%) with bulbar urethral stricture. Mean stricture length was 50mm (range 35-60mm). Stricture etiology was trauma in 3 (42.9%) patients, iatrogenic in 1 (14.3%) patient, and idiopathic in 3 (42.9%) patients. Two patients (28.6%) had previously undergone ventral buccal mucosa urethroplasty. Mean bladder mucosal graft length was 52.86mm (± 13.801), and mean harvest time was 46.43min (± 14.639). Dorsal onlay urethroplasty using bladder mucosa was successfully completed in 5 patients (71.4%). Two patients (28.6%) couldn't have the procedure completed using bladder mucosa, one due to thermal damage of the graft during harvesting, and one due to insufficient graft length. In both cases the procedure was completed using buccal mucosa. Two patients (28.6%) experienced minor hematuria between the twelfth and eighteenth postoperative day, but neither required hospitalization and/or additional procedures. All patients achieved normalization of peak flow, and this was maintained throughout the follow-up period. Mean peak flow was 17.8 ml/s (± 3.271) at 30 days, 20.6 ml/s (± 5.413) at 90 days, and 19.6 ml/s (± 8.019) 180 days. Mean IPSS score decreased from 19.3 to 5.4. Similar improvements were also seen in the ICIQ-MLUTS Score (a mean drop from 3.8 to 2.0) and Peeling's Voiding Picture Score (a mean drop from 4.0 to 2.2). Quality of Life improved post urethroplasty, with increases in EQ-5D (from 0.6371 to 0.7285) and EQ-VAS (from 58.0 to 84.0).

CONCLUSION

Transurethral harvesting of bladder mucosa using the Holmium laser (Ho-YAG) is feasible and reproducible. Our preliminary experience suggests that bladder mucosa grafts achieve comparable results to other grafts when used for dorsal onlay urethroplasty. Further research is needed to confirm these results.

Oral adverse outcomes associated with the buccal mucosa graft for urethroplasty

OBJECTIVE

The buccal mucosa graft (BMG) is the standard graft for reconstructive urology, but management of the donor site remains under debate. The authors compared postoperative oral adverse outcomes between management methods (closure, nonclosure, or xenograft-assisted closure).

STUDY DESIGN

A retrospective cohort study was conducted, enrolling patients treated at Harborview Medical Center, Seattle, Washington. The patients had a history of urethroplasty using a unilateral BMG, and the primary outcome variables were postoperative oral adverse outcomes, defined as subjective changes in mouth opening, smile, chewing, speech, intraoral bleeding, paresthesia, trismus, and infection. Multivariate and regression analyses were performed.

RESULTS

The sample was composed of 137 patients (95% male; mean age, 48 years). The mean surface areas of the BMG for closure, nonclosure, and xenograft were 1059, 1178, and 1228 mm², respectively. Thirty-four patients completed the survey (7 closure, 17 nonclosure, and 10 xenograft). Multiple linear regression showed a significant difference between the 3 groups with respect to patient-reported chewing ability and trismus favoring xenograft at larger graft sizes (P < .01).

CONCLUSIONS

Xenograft-assisted closure may reduce long-term oral adverse outcomes associated with trismus and subjective changes in chewing, mouth opening, speaking, and smiling with larger grafts. In addition, limited postoperative patient education for oral rehabilitation exercises was noted.

Onlay Pedicled Transverse Skin Flap versus One-Stage Inlay Buccal Mucosal Graft in Penile Urethroplasty: A Prospective Matched-Pair Analysis

INTRODUCTION

The aim of this study was to compare urethroplasty using onlay pedicled transverse skin flap (PSF) versus one-stage inlay buccal mucosa graft (BMG) in repair of penile urethral strictures.

METHODS

We conducted a prospective matched-pair analysis of 44 male patients receiving penile urethroplasty between June 2016 and June 2019. There were 22 patients who received PSF and 22 patients who received BMG. Matching was performed according to stricture length. Patients with strictures caused by lichen sclerosus, prior hypospadias repair, or failed prior urethroplasty were excluded. Treatment was considered successful if no recurrence was observed. Successful repair, complication rates, patients' satisfaction, and quality of life improvement were endpoints of this study.

RESULTS

Mean follow-up was 40.3 months. PSF and BMG showed comparable success rates (90.9% vs. 86.4%, p = 0.713). Recurrent stricture occurred in 2 patients (9.1%) who received PSF and in 3 patients (13.6%) who received BMG. Operation time was significantly longer for PSF than for BMG (108.4 min vs. 78.1 min, p = 0.01). Univariable logistic regression analysis revealed no relevant risk factors for stricture recurrence.

CONCLUSION

Early results indicate comparable success rates of PSF and BMG in penile urethroplasty. Further studies with larger sample size and longer follow-up periods are required to evaluate subtle differences between both techniques.

Buccal mucosal graft urethroplasty in male cats with traumatic complete urethral rupture

OBJECTIVE

To evaluate the feasibility of buccal mucosal graft urethroplasty for repairing complete urethral rupture in cats.

ANIMALS

15 male domestic shorthair cats with traumatic complete urethral rupture.

PROCEDURES

In each cat, a section of buccal mucosa was harvested, sutured, and formed into a tubule by use of an 8F indwelling catheter as support. This tubular graft was connected to both ruptured ends of the urethra to renew the urinary passage. The catheter was left in place until the absence of leakage was confirmed by positive contrast retrograde urethrography. After spontaneous urination was confirmed, cats were discharged from the hospital. Six months later, urethrography was repeated and owners were asked to score their cats' urinary function and quality of life.

RESULTS

13 cats recovered well following surgery, with no complications in the oral cavity or surgical site and no signs of difficulty or discomfort when urinating. Urethrography 2 weeks and 6 months after surgery revealed no stricture or leakage in the abdominal cavity. The 2 remaining cats developed a urethral stricture and underwent second surgery with a successful outcome. At the 6-month follow-up, 14 cats had only mild urinary signs, and 1 cat had incontinency. Owners indicated they were delighted (n = 14) or pleased (1) with their cats' quality of life.

CLINICAL RELEVANCE

Buccal mucosa was found to be a good source of graft tissue for performance of urethroplasty in male cats, yielding satisfactory outcomes with few postoperative complications. The described technique may be suitable for severe and complicated cases of urethral rupture in male cats.

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.

Recurrent Anterior Urethral Stricture: Challenges and Solutions

Recurrent male anterior urethral stricture disease is a complex surgical challenge that should be managed by reconstructive urologists with experience in stricture management. Diagnosis of recurrence requires both anatomic narrowing and patient symptoms identified on validated questionnaires, with limited role for intervention in asymptomatic treatment “failures”. Endoscopic management has a very specific role in recurrence, and the choice of technique for urethroplasty depends on pre-operative urethrography and cystoscopy. Surgical success depends on addressing patient concerns, complete stricture excision, tissue quality optimization, and the use of multi-stage repair when indicated. Augmentation with genital skin flaps and/or grafts is often required, with buccal mucosa as the ideal graft source if local tissue is compromised. Salvage options including urinary diversion and perineal urethrostomy must also be considered in debilitated patients with severe disease or repeated treatment failures. Unique patient populations including patients with hypospadias and lichen sclerosis are among the highest risk for repeated recurrence and require special care in surgical technique, graft selection, and post-operative management.

Recent Advances in treatment of urethral stricture disease in men

Urethral stricturing is a narrowing of the urethral lumen as a result of ischaemic spongiofibrosis. The main challenge of currently available treatment options is recurrence of the stricture. Recent advancements in the treatment of urethral strictures mainly came from the fields of regenerative medicine and tissue engineering. Research efforts have primarily focused on decreasing the recurrence of stricture after internal urethrotomy and constructing tissue-engineered urethral substitutes to improve clinical outcomes of urethroplasty surgeries. The aim of this article is to review the most recent advancements in the management of urethral stricture disease in men.

Combined Dorsal Plus Ventral Double Tunica Vaginalis Graft Urethroplasty: An Experimental Study in Rabbits

OBJECTIVE

To investigate the efficacy of a combined dorsal plus ventral double tunica vaginalis graft for urethral reconstruction in a rabbit model through radiology and histopathology.

METHODS

Thirty adult male New Zealand rabbits were randomly divided into 6 groups as follows (n = 5): normal, stricture, and experimental groups A, B, C, and D. In the stricture and experimental groups, the ventral urethra was incised longitudinally, and the dorsal and ventral urethral mucosa were partially removed. Then, 3 × 20 mm and 5 × 20 mm tunica vaginalis grafts were obtained to repair the dorsal and ventral urethral mucosa defects, respectively, and the spongiosum was closed in the experimental groups. The urethral defects were not repaired in the stricture group. The rabbits in experimental groups A, B, C, and D were sacrificed at 2 weeks, 4 weeks, 12 weeks, and 24 weeks postoperatively, respectively, and the rabbits in the stricture group were sacrificed at 4 weeks postoperatively. The urethra was harvested for histological analysis. Urethrography was performed before sacrifice in the stricture group and experimental groups B and D.

RESULTS

The retrograde urethrogram showed that all rabbits in experimental groups B and D had a patent urethra. Histological examination showed that the tunica vaginalis graft completely integrated into the urethra at 4 weeks postoperatively and transformed into a urinary pseudostratified epithelium at 12 weeks postoperatively.

CONCLUSION

Combined dorsal plus ventral double tunica vaginalis graft urethroplasty is a feasible technique for urethral reconstruction in a rabbit model.

Lingual mucosal graft urethroplasty 12 years later: Systematic review and meta-analysis

Objective

To evaluate the functional results and complications of the lingual mucosal graft (LMG) urethroplasty and to sum up the current state of the art of this surgical technique.

Methods

A systematic search of PubMed and Scopus electronic databases was performed, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies involving male patients treated with LMG urethroplasty for urethral stricture were included. Complete protocol is available at http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017080121. A meta-analysis comparing functional and long-term oral complication outcomes of LMG and buccal mucosal graft (BMG) was performed, calculating the odds ratio (OR) and 95% confidence interval (CI).

Results

Twenty original articles were included in the qualitative analysis. Strictures of 1.5-16.5 cm have been treated with LMG urethroplasty, due to the improvement of harvesting technique and very low rate of long-term oral complications. Very good functional results have been reported by different authors for LMG urethroplasty, with lower rate of oral complications than BMG. The meta-analysis included six comparative studies involving 187 and 178 patients treated with LMG and BMG urethroplasty, respectively. An OR of 1.65 (95% CI [0.95-2.87], I ² = 0%) and 0.18 (95% CI [0.03-1.26], I ² = 68%) were found for LMG vs. BMG urethroplasty, in terms of success and oral complication rate, respectively.

Conclusion

LMG urethroplasty can be reasonably considered a first choice technique for urethral stricture with very good results. Oral complications are temporary and minimally disabling, basically less than those for BMG, and depend mainly on the graft extent.

Free bladder mucosa graft harvested by water-jet: A novel, minimally invasive technique for urethral reconstruction

The aim of the current study was to describe a novel approach of urethral reconstruction through minimally invasive harvesting of the bladder graft via endoscopic sub-mucosal dissection of water-jet. The records of two patients were reviewed, who underwent transurethral endoscopic surgical bladder mucosa graft harvest by water-jet and urethral reconstruction with informed consent. Case 1 was a 35-year-old male with anterior urethral stricture; case 2 was a 22-year-old male with secondary anterior urethral stricture and hypospadias following a failed hypospadias surgery. The two male patients successfully underwent urethral reconstruction using bladder mucosa graft harvested via endoscopic assisted by water-jet; no perforation, cysthemorrhagia or any other postoperative bladder-related complication was observed. Voiding cystourethrogram of case 1 indicated that the reconstructed urethra was unobstructed, and no recrudescence was observed within 4 months of follow-up. In case 2, dysuria had disappeared completely within 1 month of follow-up, and the urethra plate was successfully reconstructed by first-stage. To the best of our knowledge, this is the first report to demonstrate urethral reconstruction using a bladder mucosa graft harvested by transurethral endoscopic sub-mucosal dissection, assisted by water-jet. Transurethral endoscopic surgery may provide a minimally invasive approach instead of the traditional open surgery for harvesting bladder mucosa graft. Urethral reconstruction conducted with bladder mucosa graft harvested via endoscopic sub-mucosal dissection assisted by water-jet is a feasible and safe method, and the short-term follow-up results are encouraging.

Refractory Urethral Stricture Management: Indications for Alternative Grafts and Flaps

PURPOSE OF REVIEW

Urethral strictures that are refractory to initial management present unique challenges to the reconstructive surgeon. Treatment trends have shifted as new tissue resources are becoming available. There is renewed interest in old methods as skill and technique have improved. We describe the scope of the surgical armamentarium available to develop creative approaches and successful outcomes.

RECENT FINDINGS

We discuss techniques to maximize the availability of oral mucosa, harvest and use of rectal mucosa, and developments in tissue engineering. Evolving methods to assess success of repair are also described. Urethral reconstruction for refractory urethral strictures requires proficiency with multiple methods as these strictures often require combining techniques for successful treatment.

Autologous granulation tissue tubes for replacement of urethral defects: An experimental study in male rabbits

INTRODUCTION

Tubularized urethroplasty is commonly performed in clinical practice using genital skin flaps, bladder mucosa, and buccal mucosa. However, the long-term effects are not satisfying, and donor site morbidities remain a problem. Besides, those grafts are unavailable with malignant conditions of the urinary tract, a history of lichen sclerosis, or oral disease.

OBJECTIVE

An autologous granulation tissue tube of any required length and diameter can be produced by implanting foreign objects subcutaneously (Summary Fig.). The current study aimed to investigate to what extent of length this fully autologous tissue could be used for tubularized urethroplasty, satisfying urethral patency and tissue regeneration, in male rabbits.

STUDY DESIGN

Twenty-seven New Zealand male rabbits were randomly divided into three groups. Silastic tubes were implanted subcutaneously in Group 1 and Group 2. By 2 weeks the granulation tissue encapsulating the tubes was harvested. In Group 1, pendulous urethral segments of 1 cm were excised, and urethroplasty was performed with the granulation tissue tube in an end-to-end fashion. In Group 2, a pendulous urethral segment of 1.5 cm was replaced with the tissue tube. In Group 3, a pendulous urethral defect of 1 cm was repaired by re-anastomosis as control. Serial urethrograms were performed at 1, 2 and 6 months postoperatively. Meanwhile, the neo-urethra were harvested and analyzed grossly and histologically.

RESULTS

The urethrograms showed that all animals in Group 1 maintained a wide urethral caliber. In contrast, animals in Group 2 and Group 3 developed progressive strictures. Histologically, an intact urothelium with one to two cell layers lined the graft by 1 month, which was surrounded by increasing organized smooth muscle in Group 1. By 6 months, the grafts were completely integrated into native urethra. Nevertheless, extensive fibrosis occurred in Group 2 and Group 3.

DISCUSSION

The tissue successfully maintained patency and guided urethral regeneration across a distance of 1 cm. As an epithelium-free graft, the tissue showed better results than acellular matrix for tubularized urethroplasty compared with previous studies. Nevertheless, several limitations existed: (1) the urethral defect was created in healthy urethra, which could not fully simulate the clinical situation; (2) as a small animal model, rabbit was less informative for clinical problems; (3) the tissue was inadequate for long segmental urethral replacement. Further study is needed before the procedure is used clinically.

CONCLUSION

An autologous granulation tissue tube grown subcutaneously could be successfully used to repair urethral defects of 1 cm in male rabbits.

A brief review on anterior urethral strictures

The treatment of urethral strictures remains a challenging field in urology even though there are a variety of procedures to treat it at present, as no one approach is superior over another. This paper reviewed the surgical options for the management of different sites and types of anterior urethral stricture, providing a brief discussion of the controversies regarding this issue and suggesting possible future advancements. Among the existing procedures, simple dilation and direct vision internal urethrotomy are more commonly used for short urethral strictures ( <1 cm, soft and no previous intervention). Currently, urethroplasty using buccal mucosa or penile skin is the most widely adopted clinical techniques and have proved successful. Nonetheless, complications such as donor site morbidity remain problem. Tissue engineering techniques are considered as a promising solution for urethral reconstruction, but require further investigation, as does stem cell therapy.

Use of a fibrovascular tube in creation of neo-urethra during penile reconstruction

INTRODUCTION

There are several techniques employed in the surgical treatment of total or partial penile reconstruction, hypospadias surgery, and urethral stricture. Urethral reconstruction is performed in different ways applying these techniques.

OBJECTIVE

We evaluated use of a fibrovascular sheath to create a neo-urethra formed around a silicon tube.

MATERIAL AND METHODS

We used nine male New Zealand rabbits for this study. In the first step, we placed a silicone tube under the skin in the lower abdomen of the rabbits and waited for the formation of a fibrovascular sheath to totally surround the tube. In the second step, the silicone tube was removed and the formed fibrovascular sheath was anastomosed with penile urethra over a silicone 8F Foley catheter. Ten days after the second step, the silicone Foley catheter was removed. Twenty days after the second step, we evaluated the newly created neo-urethra with a retrograde urethrogram. Thirty days after the second step, the rabbits were sacrificed and the bladder, urethra, and neo-urethra were removed for histopathological examination.

RESULTS

Six of the rabbits completed the study. After the first operation, in the third month, formation of the fibrovascular sheath was observed around the silicon tube. After anastomosis and removal of the silicon Foley catheter, urine was seen to pass through the neo-urethral meatus. Urethrocystography showed that the neo-urethra and penile urethra were aligned and urine flow was regular. Histopathological evaluation showed that the structural integrity of the newly formed urethra was comparable with the structure of the regular urethra (Table) and the calibration did not change over time, although the newly formed urethra was not covered with uroepithelium.

CONCLUSIONS

In this study, we achieved promising results with use of a newly formed fibrovascular sheath as a neo-urethra.

Proximal hypospadias repair with bladder mucosal graft: Our 10 years experience

INTRODUCTION AND OBJECTIVE

A great variety of different surgical techniques has been described for proximal hypospadias repair and an ideal tissue has not been determined yet. We present our 10 years of surgical experience using a bladder mucosal graft for urethroplasty.

STUDY DESIGN

Bladder mucosal graft urethroplasty was performed between 2005 and 2015 in 50 patients with severe proximal hypospadias. The mean age of patients was 45.1 months (range 24-164 months). Hypospadias were perineal in 18 patients, scrotal in 22, and penoscrotal in 10. In all cases a chordee correction was performed and median time between the first and the second stages was 12 months (mean 17 months, range 4-68 months). Both foley catheter and a suprapubic cystostomy were positioned and maintained for 2-4 weeks. Follow-up was performed at 1-3 and 6-12 months after surgery, and afterwards annually with clinical examination and flowmetry test.

RESULTS

Mean follow-up was 5.3 years (median 5, range 1-10 years). Mean graft length was 57.4 mm (median 55 mm, range 35-85 mm). Among all the only early complication registered was a postoperative infection in one patient (2%) at the site of anastomosis. The long-term complications observed were urethrocutaneous fistula in nine patients (18%), urethral stricture in 15 patients (30%), meatal stricture in four patients (8%), and prolapse of meatus in seven patients (14%). The mean time of complication occurrence was 15 months (median 15.5 months, range 1-96 months). The functional and cosmetic appearance after surgery was satisfactory in 42/50 patients (84%) during the follow-up period.

DISCUSSION

There is still an open debate regarding the optimal surgical approach for management of severe proximal hypospadias. Compared with other approaches, our technique showed acceptable results even though encumbered by slightly higher complication rates.

CONCLUSION

Our results show that bladder mucosal graft for primary severe proximal hypospadias in selected patients is a possible alternative to other commonly used techniques, with the aim of restoring recovery of the normal continuity of the distal urinary tract see figure below.

Urethral Reconstruction Using Mesothelial Cell-Seeded Autogenous Granulation Tissue Tube: An Experimental Study in Male Rabbits

Objective. This study was to evaluate the utility of the compound graft for tubularized urethroplasty by seeding mesothelial cells onto autogenous granulation tissue. Methods. Silastic tubes were implanted subcutaneously in 18 male rabbits, of which nine underwent omentum biopsies simultaneously for in vitro expansion of mesothelial cells. The granulation tissue covering the tubes was harvested 2 weeks after operation. Mesothelial cells were seeded onto and cocultured with the tissue for 7 days. A pendulous urethral segment of 1.5 cm was totally excised. Urethroplasty was performed with mesothelial cell-seeded tissue tubes in an end-to-end fashion in nine rabbits and with unseeded grafts in others as controls. Serial urethrograms were performed at 1, 2, and 6 months postoperatively. Meanwhile, the neourethra was harvested and analyzed grossly and histologically. Results. Urethrograms showed cell-seeded grafts maintained wide at each time point, while strictures formation was found in unseeded grafts. Histologically, layers of urothelium surrounded by increasingly organized smooth muscles were observed in seeded grafts. In contrast, myofibroblasts accumulation and extensive scarring occurred in unseeded grafts. Conclusions. Mesothelial cell-seeded granulation tissue tube can be successfully used for tubularized urethroplasty in male rabbits.

New frontiers in urethral reconstruction: injectables and alternative grafts

Contemporary management of anterior urethral strictures requires both endoscopic as well as complex substitution urethroplasty, depending on the nature of the urethral stricture. Recent clinical and experimental studies have explored the possibility of augmenting traditional endoscopic urethral stricture management with anti-fibrotic injectable medications. Additionally, although buccal mucosa remains the gold standard graft for substitution urethroplasty, alternative grafts are necessary for reconstructing particularly complex urethral strictures in which there is insufficient buccal mucosa or in cases where it may be contraindicated. This review summarizes the data of the most promising injectable adjuncts to endoscopic stricture management and explores the alternative grafts available for reconstructing the most challenging urethral strictures. Further research is needed to define which injectable medications and alternative grafts may be best suited for urethral reconstruction in the future.

Tissue transfer techniques in reconstructive urology

Tissue transfer techniques are an essential part of the reconstructive urologist's armamentarium. Flaps and graft techniques are widely used in genital and urethral reconstruction. A graft is tissue that is moved from a donor site to a recipient site without its native blood supply. The main types of grafts used in urology are full thickness grafts, split thickness skin grafts and buccal mucosa grafts. Flaps are transferred from the donor site to the recipient site on a pedicle containing its native blood supply. Flaps can be classified based on blood supply, elevation methods or the method of transfer. The most used flaps in urology include penile, preputial, and scrotal skin. We review the various techniques used in reconstructive urology and the outcomes of these techniques.

Tunneled buccal mucosa tube grafts for repair of proximal hypospadias

PURPOSE

Buccal mucosa is the favored graft material for patients with long urethral defects and a paucity of skin. Since 2007, we have used the novel tunneled buccal mucosa tube graft urethroplasty technique in these patients. We describe this operative technique and report our surgical and functional outcomes.

MATERIALS AND METHODS

Between 2007 and 2013, 37 males with proximal hypospadias underwent tunneled buccal mucosa tube graft urethroplasty. After the penile shaft was optimized at a prior stage a free buccal graft was tubularized and tunneled under the intact ventral shaft skin and into the glans. We retrospectively reviewed all charts to report our results. We assessed uroflowmetry and bladder ultrasound for post-void residual urine.

RESULTS

The overall complications rate in 34 patients with more than 1-year followup was 32% (11), including fistula in 5, proximal stricture in 4 and meatal stenosis in 2. In the first 10 patients a total of 7 complications (70%) developed but there were only 4 complications in the next 24 (16%). Surgeon experience was the only significant predictor of complications (p = 0.003). We obtained uroflow and post-void residual urine data on 13 of 37 patients, of whom 9 achieved a normal flow pattern and post-void residual urine, and 4 had a blunted flow pattern.

CONCLUSIONS

The novel technique of the tunneled buccal mucosa tube graft in patients with proximal hypospadias represents a good alternative for a long urethroplasty in patients with a paucity of skin. After the learning curve plateaus the rate and degree of complications decrease. Furthermore, voiding function is adequate, as assessed by uroflow studies and post-void residual urine measurement.

Tissue engineered buccal mucosa for urethroplasty: progress and future directions

PURPOSE

Autologous buccal mucosa is commonly utilized in the surgical treatment of urethral strictures. Extensive strictures require a larger quantity of tissue, which may lead to donor site morbidity. This review assesses progress in producing tissue engineered buccal mucosa as an alternative graft material.

RESULTS

Few clinical studies have introduced cells onto biological or synthetic scaffolds and implanted resulting constructs in patients. The available studies show that buccal mucosa cells on acellular human dermis or on collagen matrix lead to good acute stage tissue integration. Urothelial cells on a synthetic substrate also perform well. However while some patients do well many years post-grafting, others develop stricture recurrence. Acellular biomaterials used to treat long urethral defects in animals commonly lead to fibrosis.

CONCLUSIONS

Tissue engineered buccal mucosa shows promise as a substitute for native tissue. The fibrosis which occurs months post-implantation may reflect the underlying disease process recurring in these patients.

Free tubularised vesical mucosa graft for congenital stenosis of the urethra in children

BACKGROUND

Reconstruction of urethral strictures in children remains a challenge to the pediatric surgeon as these are often related to different rare congenital anomalies with various clinical presentations that endanger renal function and should be repaired in young children. Multiple techniques have been described for their repair. We aimed to determine whether the use of a free tubularised bladder mucosal graft associated to a prior tubeless vesicostomy was feasible and sure, as this technique of reconstruction using tubularised grafts has not been described yet in young children.

RESULTS

Two newborn male patients were referred to our department. Both presented a congenital stenosis of the urethra as a part of a complex urethral malformation. Surgery involved prior tubeless vesicostomy, free bladder mucosal graft for urethral reconstruction, and vesicostomy closure for both children. Postoperative evolution was satisfying in both children and cystourethroscopy showed permeable urethra. Satisfying cosmetic and functional results have been obtained in the two cases.

CONCLUSIONS

The prior vesicostomy prevents kidney damage in the context of complex genital and urinary malformations. Bladder mucosa's immunohistological properties are the most similar to those of the urethral tissue, and are appropriate for this type of correction, making our technique feasible and sure.

LEVEL OF EVIDENCE

5.

Graft surgery in extensive urethral stricture disease

Surgical treatment of long urethral stricture disease remains one of the most challenging problems in urology. In recent years there has been continuous discussion with regard to the etiology, location, length, and management of extensive urethral stricture disease. Various tissues such as genital and extragenital skin, buccal mucosa, lingual mucosa, small intestinal submucosa, and bladder mucosa have been proposed for urethral reconstruction. The most frequent questions pertain to the optimal technique for urethroplasty and the optimal graft for substitution urethroplasty, as judged by both patient satisfaction and outcome success. We review the recent literature with respect to any new information on graft urethroplasty for extensive urethral stricture.

Evaluation of crural release and ischial osteotomy for relief of tension in the repair of large segmental urethral defects in male cats

OBJECTIVE

To examine if the tension at the site of a urethral anastomosis can be relieved by performing either a crural release technique or an ischial osteotomy technique.

STUDY DESIGN

Cadaveric study and 2 case reports.

ANIMALS

Adult male cat cadavers (n = 18).

METHODS

Cats were divided into 2 groups; crural release (n = 9) and ischial osteotomy (n = 9). In each group, 20%, 25%, and 30% of the pelvic urethra was excised in 3 cats. The length of the urethral defect was measured after excision of the urethral segment, and after approximation, before and subsequent to the tension relieving technique performed. Two clinical cases are described.

RESULTS

Both crural release and ischial osteotomy were effective in relieving the tension encountered at the urethral anastomosis after removal of 20% of the urethral length. In the ischial osteotomy group, apposition without tension after removing up to 30% of the intrapelvic urethral length was easily achieved. A similar technique was successfully used in 2 clinical cases.

CONCLUSION

Crural release and ischial osteotomy techniques allow approximation and tension free anastomosis of large segmental defects of the pelvic urethra in cats.

Cell-seeded tubularized scaffolds for reconstruction of long urethral defects: a preclinical study

BACKGROUND

The treatment options for patients requiring repair of a long segment of the urethra are limited by the availability of autologous tissues. We previously reported that acellular collagen-based tubularized constructs seeded with cells are able to repair small urethral defects in a rabbit model.

OBJECTIVE

We explored the feasibility of engineering clinically relevant long urethras for surgical reconstruction in a canine preclinical model.

DESIGN, SETTING, AND PARTICIPANTS

Autologous bladder epithelial and smooth muscle cells from 15 male dogs were grown and seeded onto preconfigured collagen-based tubular matrices (6 cm in length). The perineal urethral segment was removed in 21 male dogs. Urethroplasties were performed with tubularized collagen scaffolds seeded with cells in 15 animals. Tubularized constructs without cells were implanted in six animals. Serial urethrography and three-dimensional computed tomography (CT) scans were performed pre- and postoperatively at 1, 3, 6, and 12 mo. The animals were euthanized at their predetermined time points (three animals at 1 mo, and four at 3, 6, and 12 mo) for analyses.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Statistical analysis of CT imaging and histology was not needed.

RESULTS AND LIMITATIONS

CT urethrograms showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices. The urethral segments replaced with acellular scaffolds collapsed. Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis. Histologically, an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs, and cellular organization increased over time. The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and smooth muscle-specific desmin. Formation of an epithelial cell layer occurred in the unseeded constructs, but few muscle fibers formed.

CONCLUSIONS

Cell-seeded tubularized collagen scaffolds can be used to repair long urethral defects, whereas scaffolds without cells lead to poor tissue development and strictures. This study demonstrates that long tissue-engineered tubularized urethral segments may be used for urethroplasty in patients.

Tubal Buccal Mucosa Graft without Anastomosis of the Proximal Urethra for Long Segment Posterior Urethral Defect Repair

A 31-year-old man was referred for further management of a urethral stricture. He was a victim of a traffic accident and his urethral injury was associated with a pelvic bone fracture. He had previously undergone a suprapubic cystostomy only owing to his unstable general condition at another hospital. After 3 months of urethral injury, direct urethral anastomosis was attempted, but the surgery failed. An additional 4 failed internal urethrotomies were performed before the patient visited Chungbuk National University Hospital. Preoperative images revealed complete posterior urethral disruption, and the defect length was 4 cm. We performed a buccal mucosa tubal graft without anastomosis of the proximal urethra for a long segment posterior urethral defect. The Foley catheter was removed 3 weeks after the operation and the patient was able to void successfully. After 8 months, he had normal voiding function without urinary incontinence.

Management of severe hypospadias

Many classifications of hypospadias have been published, mainly based on the position of the ectopic meatus, which is an insufficient criterion to define the severity of this malformation. What really marks the proximal landmark of this malformation is the level of division of the corpus spongiosum, which is always proximal to the ectopic meatus. In this article, we will focus on the most severe forms of hypospadias which include those with a proximal division of corpus spongiosum (below the midshaft), important chordee and a poor development of the ventral radius, reflecting a marked hypovirilization of the genital tubercle, and cripple hypospadias resulting from several previous failed surgical procedures. The principle of hypospadias surgery will be reviewed together with the outcome of the current surgical techniques. Furthermore, common complications will be outlined. There is no minor or major hypospadias and all forms require a solid experience of the surgeon, as minor looking hypospadias may turn out to be far more complex to repair than they appear once the ventral radius of the penis has been dissected.

Management of anterior urethral stricture: an evidence-based approach

PURPOSE OF REVIEW

To provide a review of the latest evidence on the management of anterior urethral strictures.

RECENT FINDINGS

A continuing role exists for urethrotomy or dilatation in the management of urethral strictures as first-line therapy in selected patients. In those patients with bulbar strictures who fail or are not suitable for these procedures, an anastomotic urethroplasty, and if not feasible a substitution urethroplasty using either a flap or oral mucosal graft either by a dorsal, lateral or ventral onlay approach should be considered. For penile strictures, a ventral onlay procedure using skin can be considered except in cases of lichen sclerosis when an onlay procedure utilizing oral mucosa provides the best results using either a one-stage or two-stage approach.

SUMMARY

Various options exist for the management of anterior urethral stricture disease. The 'reconstructive ladder' has served to guide urologists over the years. The selection of the correct procedure should be patient-centred and based on the latest evidence.

Original Koyanagi urethroplasty versus modified Hayashi technique: outcome in 57 patients

OBJECTIVE

To compare outcomes of the original Koyanagi technique with the Hayashi modification in severe hypospadias, i.e. hypospadias with a division of the corpus spongiosum located behind the penile midshaft associated with marked hypoplasia of the ventral aspect of the penis and a non-preservable urethral plate. Choice of technique for treating severe hypospadias is discussed.

PATIENTS AND METHODS

Twenty-six patients (group I) were operated in Lyon using the original Koyanagi procedure and 31 (group II) underwent a modified Hayashi procedure in Paris. Most patients received preoperative androgenic stimulation. Mean follow up was 25 months (group I) and 34 months (group II).

RESULTS

Sixteen patients (61.5%) in group I and 19 (61.3%) in group II developed complications leading to 21 additional procedures in each group. Urethral dehiscence was found in 11/26 patients in group I (42.3%), and in 6/31 patients in group II (19.3%); fistulae were respectively found in 5/26 (19.2%) and 12/31 (38.7%), and stenosis in 9/26 (34.6%) and 5/31 (16.1%) patients. Urethrocele was found in 7/26 (26.9%) and 5/31 (16%) patients, respectively. Twelve (group I) and 7 (group II) patients are awaiting re-operation.

CONCLUSION

Although the complication rate is quite similar between the original and the modified Koyanagi procedure, the Hayashi technique seems to provide a better distal blood supply to the reconstructed urethra.

Application of amniotic membrane as xenograft for urethroplasty in rabbit

OBJECTIVES

Uroepithelium repair has always been the subject of discussion in urology surgeries. Using human amniotic membrane allograft has already proved to be useful in other fields. In this study, we use amniotic membrane to repair uroepithelium injuries in rabbits.

METHODS

Twenty healthy rabbits underwent surgery to induce a 10-mm incision, 10 mm from the meatus on ventral part of the urethra. Then a 5 x 10 mm patch of amniotic membrane was sutured to the incised urethra. All of the rabbits were catheterized for a week and then the patches were removed. The rabbits were studied for a month for any signs of infection and fistula formation.

RESULTS

All samples revealed complete re-epithelialization of reconstructed urethra by transitional epithelium. There was one case of infection and following fistula (5%). There were two cases of urethral strictures (10%).

CONCLUSION

The result from this study suggests that amniotic membrane is an inexpensive, easy, and biodegradable graft with very little antigen effect which seems to be the ideal solution for urethroplasty.

Tubularized urethral replacement with unseeded matrices: what is the maximum distance for normal tissue regeneration?

PURPOSE

Complete urethral replacement using unseeded matrices has been proposed as a possible therapy in cases of congenital or acquired anomalies producing significant defects. Tissue regeneration involves fibrin deposition, re-epithelialization, and remodeling that are limited by the size of the defect. Scar formation occurs because of an inability of native cells to regenerate over the defect before fibrosis takes place. We investigated the maximum potential distance of normal native tissue regeneration over a range of distances using acellular matrices for tubular grafts as an experimental model.

MATERIALS AND METHODS

Tubularized urethroplasties were performed in 12 male rabbits using acellular matrices of bladder submucosa at varying lengths (0.5, 1, 2, and 3 cm). Serial urethrography was performed at 1, 3, and 4 weeks. Animals were sacrificed at 1, 3, and 4 weeks and the grafts harvested. Urothelial and smooth muscle cell regeneration was documented histologically with H&E and Masson's trichrome stains.

RESULTS

Urethrograms demonstrated normal urethral calibers in the 0.5 cm group at all time points. The evolution of a stricture was demonstrated in the 1, 2, and 3 cm grafts by 4 weeks. Histologically all grafts demonstrated ingrowth of urothelial cells from the anastomotic sites at 1 week. By 4 weeks, the 0.5 cm grafts had a normal transitional layer of epithelium surrounded by a layer of muscle within the wall of the urethral lumen. The 1, 2, and 3 cm grafts showed ingrowth and normal cellular regeneration only at the anastomotic edges with increased collagen deposition and fibrosis toward the center by 2 weeks, and dense fibrin deposition throughout the grafts by 4 weeks.

CONCLUSIONS

The maximum defect distance suitable for normal tissue formation using acellular grafts that rely on the native cells for tissue regeneration appears to be 0.5 cm. The indications for the use of acellular matrices in tubularized grafts may therefore be limited by the size of the defect to be repaired.

The multistage use of buccal mucosa grafts for complex hypospadias: histological changes

PURPOSE

We report our experience using buccal mucosa in the multistage repair of complex hypospadias, and the observed histological changes.

MATERIALS AND METHODS

We evaluated 31 patients (14 adults and 17 children). A total of 19 patients presented after failed hypospadias repair with deficient ventral skin, 5 presented with scrotal hypospadias and 7 presented with perineal hypospadias. Patients who had previously undergone hypospadias repair had 3 to 7 failed trials. Two stage buccal mucosa graft was performed using the Bracka technique. In the first stage residual fibrosis was released, the glans was split and the buccal mucosa graft was sutured to the ventral surface of the penis to form a future urethral plate. Second stage reconstruction was performed after 6 months with interposed scrotal dartos tissue. Buccal mucosa was histologically studied before grafting, and at 6 months after graft uptake and exposure to the air.

RESULTS

Buccal mucosa free graft showed excellent uptake within 5 days in all cases. At 6 months the buccal mucosa was well vascularized and pliable. Minute fistulas occurred in 3 cases (9.7%), which were closed at a later stage. Histological analysis of buccal mucosa tissues before and after graft and prolonged exposure to the air (more than 6 months) was conducted. The buccal mucosa displayed epithelial hyperplasia with mild and focal keratinization. The lamina propria was slightly edematous and minimally infiltrated by mononuclear inflammatory cells. The lamina propria papillae were elongated, extending to 75% of the mucosal thickness compared to the normal buccal mucosa. The buccal mucosal graft displayed good vascularization, similar to that of the normal mucosa.

CONCLUSIONS

Multistage repair using buccal mucosa is an excellent option for urethral reconstruction. It guarantees excellent graft uptake and good vasculature, which improves success. It also provides supple tissue for glanular and urethral reconstruction in cases of severe complex hypospadias.

Ten-year experience with composite bladder mucosa-skin grafts in hypospadias repair

OBJECTIVES

A variety of surgical techniques and flaps have been described for hypospadias repair. We present our 10-year experience using a composite urethroplasty graft consisting of bladder mucosa and skin.

METHODS

We reviewed the records of 294 patients who had undergone hypospadias repair at our institution from 1993 to 2003. The meatus was penile in 221, penoscrotal in 55, and perineal in 18. They all underwent single-stage urethroplasty consisting of a composite tubularized bladder mucosa-skin graft. Patient age at surgery was 2 to 46 years old (mean 8.9).

RESULTS

Urethrocutaneous fistula formation occurred in 27 (9.1%) and urethral strictures in 9 (3.2%), for an overall complication rate of 12.3%. No proximal urethral anastomotic strictures or meatal stenosis developed.

CONCLUSIONS

Our results have demonstrated that composite bladder mucosa-skin flap grafts can be used successfully for urethral reconstruction in proximal, as well as distal, hypospadias repair. The distal tubularized skin flap prevented the occurrence of meatal stenosis.

Repair of Urethral Defects Using Fascia Lata Autografts in Dogs

OBJECTIVE

To evaluate the feasibility of urethroplasty using a free fascia lata (FL) graft in the dog.

STUDY DESIGN

In vivo experimental study.

ANIMALS

Mixed-breed dogs (n=14).

METHODS

Half of the circumference of the urethra, approximately 1.5 cm long, was excised in 14 male dogs to induce a urethral defect. FL (approximately 2 cm x 2 cm) harvested from the lateral thigh was sutured to the urethra using a 3-0 polyglactin 910 continuous pattern. Dogs were monitored daily for bladder distention and had urethral catheters until normal voiding was observed. On day 60, each dog had a positive contrast urethrogram, and then 8 dogs were euthanatized for gross and histologic examination. Six dogs were monitored for urologic problems for 6 months, and a positive contrast urethrogram was repeated.

RESULTS

All dogs recovered successfully; 4 dogs had difficulty voiding for 2-3 days and urine was aspirated from these dogs every 3 hours until signs of painful urination disappeared. On positive contrast urethrograms, urethral anatomy was considered normal except in 4 dogs that had an irregular contour. Gross urethral examination confirmed an absence of ulceration, stricture, diverticula, or fistula formation, and the FL-lined graft survived in all dogs. No degenerative and reparative responses were observed. On histologic examination of the penile urethra, the lumen was intact, covered with transitional epithelium, and surrounded by corpus spongiosum with cavernous spaces and blood-filled vessels.

CONCLUSIONS

Free FL grafts are incorporated satisfactorily and would appear to be useful for repairing urethral defects.

CLINICAL RELEVANCE

FL grafts should be considered for repair of urethral defects in dogs.

THE TUNICA VAGINALIS DORSAL GRAFT URETHROPLASTY: EXPERIMENTAL STUDY IN RABBITS

PURPOSE

We created an experimental model of urethral defect and then repaired it using a tunica vaginalis graft applied on the dorsal surface of the urethra. We studied the histological and radiological characteristics of free tunica vaginalis graft urethroplasty.

MATERIALS AND METHODS

In 20 New Zealand rabbits a dorsal urethral defect was created by excising a portion of the dorsal urethral surface. The tunica vaginalis graft was placed dorsally over the corpora cavernosa and tied with 4 interrupted sutures. The mucosal margin of the urethral defect was sutured to the graft using 6-zero polydioxanone sutures in continuous fashion. The animals were divided into 4 equal groups and were sacrificed 14 days, and 4, 8 and 12 weeks after surgery, respectively. A retrograde urethrogram was done at autopsy. The penis was sent for histological analysis and an experienced pathologist evaluated the severity of acute and chronic inflammation, foreign body reaction and scar formation.

RESULTS

There were no deaths related to the procedure and no intraoperative complications. All rabbits voided spontaneously after surgery. Retrograde urethrograms showed no fistula or stricture. As time after surgery increased, the signs of inflammation response disappeared, and the orientation of collagen fibrils and smooth muscle fascicles resembled that of a normal urethra. The mesothelial lining of the tunica vaginalis gradually became replaced by a more stratified epithelial lining, similar to the urothelial lining of the native urethra.

CONCLUSIONS

In the current study we noted that a tunica vaginalis graft placed dorsally can be a successful urethral substitute in the animal model.

[Acellular matrix for functional reconstruction of the urogenital tract. Special form of "tissue engineering"?]

Organ substitution and reconstruction of the urogenital system still poses a problem regarding an adequate substitute. Usually non-organ-specific materials are used for reconstruction (bowl, buccal mucosa). This nonspecific tissue can cause side effects that result from the origin and the natural function. Different groups have shown that an acellular matrix graft in the urinary bladder and the urethra served as a scaffold for complete regeneration of all organ wall components and that this organ-specific regeneration simultaneously facilitates functional restitution. New approaches will presumably effect better regeneration after seeding the matrix with organ-specific cells (i.e., urothelial cells). Smaller studies on genital reconstructive surgery could show that vaginal substitution with an acellular matrix might be possible or that there could be a possible substitute for the tunica during surgical treatment of Peyronie's disease.

Urethroplasty using a bovine pericardium graft: an experimental study using normal urethras from dogs

The use of bovine pericardium as a urethral patch to substitute a ventral segment of canine urethras was studied. Healing, epithelial growth, urethral permeability, fistulas, and calcification were analyzed. Thirty male mongrel dogs of medium and large size underwent resection of a ventral segment of the medial urethra measuring 2.0 x 0.5 cm, which was replaced with a bovine pericardium graft, treated with buffered glutaraldehyde and preserved in formaldehyde. Two running sutures of polygalactin 5-0 were applied, one on each side of the patch. The corpus spongiosum was closed with uninterrupted suture and the skin with interrupted suture of polygalactin 5-0. Six months later, the animals were examined and sacrificed under anesthesia. Retrograde urethrograms showed that the urethral healing was complete in six of the 30 animals, without stenosis, fistulas or dilations. Microscopic examination showed complete epithelization of these six urethras. The remaining 24 animals presented urethrocutaneous fistulas without stenosis, demonstrated by urethral catheterism using a 10-Fr plastic catheter. These data show that a successful urethral reconstruction of the penile urethra was possible in only 20% of the operated animals. Infection and leakage may be the cause of the urethrocutaneous fistulas present in 80% of cases. Further studies are necessary to determine whether such fistulas are avoidable. If they are, the bovine pericardium may well be an option in the treatment of urethral lesions in dogs.

Ulaanbaatar Procedure for Tubularization of the Glans in Severe Hypospadias

PURPOSE

We developed a new procedure for the repair of proximal hypospadias in which the distal urethra is constructed as part of the first of 2 stages, and reviewed the results of 34 cases.

MATERIALS AND METHODS

We performed stage 1 of the Ulaanbaatar procedure in 35 children 0.6 to 11 years old (average age 2.5), and stage 2 in 20. The meatus was at the posterior third of the shaft in 14 children, at the penoscrotal junction in 16 and in the perineum in 5. Three patients had a previous operation, and none had Byars flaps formed. Followup was less than 2(1/2) years for stage 1 and less than 1(1/2) years for stage 2. In 2 stage 2 procedures a free graft was also used to augment the proximal part of the urethroplasty.

RESULTS

Urethral fistula did not develop in any patient, a minor early stricture occurred in 2 patients and 1 urethral diverticulum occurred in 1 patient after stage 2. In all patients the glans and meatus were more normal compared to other 2-stage procedures after the first operation, and the cosmetic result was usually satisfactory.

CONCLUSIONS

The Ulaanbaatar technique provides an alternative approach to the formation of the glans urethra in severe hypospadias. It does not have the risks associated with a single stage procedure but has the benefit of enabling tunneling of the urethra through the glans, thus facilitating a favorable cosmetic outcome and an easy stage 2.