Staged buccal mucosa urethroplasty in reoperative hypospadias

De- and recellularized urethral reconstruction with autologous buccal mucosal cells implanted in an ovine animal model

OBJECTIVES

Patients with urethral stricture due to any type of trauma, hypospadias or gender dysphoria suffer immensely from impaired capacity to urinate and are in need of a new functional urethra. Tissue engineering with decellularization of a donated organ recellularized with cells from the recipient patient has emerged as a promising alternative of advanced therapy medicinal products. The aim of this pilot study was to develop an ovine model of urethral transplantation and to produce an individualized urethra graft to show proof of function in vivo.

METHODS

Donated urethras from ram abattoir waste were decellularized and further recellularized with autologous buccal mucosa epithelial cells excised from the recipient ram and expanded in vitro. The individualized urethral grafts were implanted by reconstructive surgery in rams replacing 2.5 ± 0.5 cm of the native penile urethra.

RESULTS

After surgery optimization, three ram had the tissue engineered urethra implanted for one month and two out of three showed a partially regenerated epithelium.

CONCLUSIONS

Further adjustments of the model are needed to achieve a satisfactory proof-of-concept; however, we interpret these findings as a proof of principle and a possible path to develop a functional tissue engineered urethral graft with de- and recellularization and regeneration in vivo after transplantation.

Grafted tubularised incised plate: A right option in the management of failed mid-penile and distal hypospadias

Introduction

Hypospadias is a common congenital anomaly of the urogenital system. The goal of the initial repair is to correct any curvature, ensuring that the penis is straight, allowing for successful intercourse, to create a functional neourethra to direct the urinary stream in a forward direction and to produce a cosmetically normal-appearing penis with a slit-like meatus at the tip of the glans. Failures and complications do occur. Failed hypospadias repair is often associated with penile skin loss or deficient local tissue, which leaves the penis short, scarred and hypovascular. Repair of a failed hypospadias surgery represents one of the most challenging and difficult tasks. We retrospectively evaluated our series of children who underwent reoperative grafted tubularised incised plate (G-TIP) repair for a mid-penile or distal penile hypospadias.

Materials and Methods

With permission obtained from the university/institutional ethics committee, we retrospectively reviewed the inpatient and outpatient records of all children ≤18 years of age who underwent a reoperative G-TIP hypospadias repair.

Results

During the study period, a total of 22 children (mean age: 6.8 years) underwent reoperative G-TIP repair. The mean number of previous repairs was 1.36. Nine (40.9%) of the children had persisting chordee. Complications were noted in five (22.7%) children.

Conclusion

G-TIP is a good option in the management of mid-penile or distal penile failed hypospadias repairs. Although complications are noted, they are easily manageable.

Vacuum physiotherapy after first stage buccal mucosa graft (BMG) urethroplasty in children with proximal hypospadias

INTRODUCTION

To assess the feasibility of vacuum physiotherapy meant to decrease graft contraction and recurrent penile curvature (PC), hence successful tubularization and a straight penis in patients underwent two-stage buccal mucosa graft (BMG) urethroplasty, in proximal hypospadias repair.

MATERIAL AND METHODS

Between January 2014 and July 2018, 59 two-stage BMG urethroplasties performed at our referral center, were included in the study. The parents were counseled to use the vacuum device between the two stages. An internal, self-administered, semiquantitative, non-validated questionnaire was designed to record parent and patient adherence to the vacuum physiotherapy and parent satisfaction. Success rate of graft tubularization, curvature correction rates, and status of early (4 months) postoperative urinary stream were evaluated.

RESULTS

Of 45/59 (76.3%) who returned the questionnaire, 77.8% followed the recommended physiotherapy protocol using the vacuum device. 93.3% of parents replied that the use of the vacuum was easy or moderately easy. None of the parents interrupted the physiotherapy because of perceived difficulty or intolerability. 100% of parents would have repeated the physiotherapy, if they had to. Overall, success rate of tubularization was 98.3% (58/59), complete curvature correction was achieved in 88.2% (52/59) of patients, and 79.7% (47/59) of patients showed a straight and powerful early post-operative urinary stream.

CONCLUSIONS

Physiotherapy with the vacuum device is safe, easy and practically feasible. Our vacuum physiotherapy protocol had high compliance rate. Vacuum physiotherapy should be considered for further assessment in patients undergoing two stage hypospadias repair using buccal mucosa.

Outcomes of staged lingual mucosal graft urethroplasty for redo hypospadias repair

BACKGROUND

The objective of this study was to present the outcomes for redo hypospadias repair using lingual mucosal graft (LMG).

PATIENTS AND METHODS

Between June 2012 and February 2017, 47 patients underwent staged LMG urethroplasty for redo hypospadias repair. The inclusion criteria were previous failed hypospadias repair with a paucity of local skin that interferes with correction using skin flaps and demands graft urethroplasty. During the first stage, a well-vascularized bed on the tunica albuginea was created. Then, the harvested LMG was secured to the prepared bed. The second-stage urethroplasty was carried out after six months. In this stage, tubularization of the previously implanted LMG was performed. In four cases, tubularization was difficult owing to graft contracture. This difficulty was managed by using the dorsally degloved penile skin as the onlay island flap in three cases and the buccal mucosa onlay graft in the fourth case. In all cases, a second protective layer from the dartos or tunica vaginalis was developed to cover the neourethra.

RESULTS

The median (interquartile range [IQR]) age of patients at the first stage was 5 (4-6) years, and the median (IQR) duration between both stages was 7 (6-8) months. The median (IQR) follow-up after the second stage was 15 (13-16) months. The median (IQR) number of previous operations was 2 (2-3). The median (IQR) length of the LMG was 3 (2.5-4) cm, and the median (IQR) width was 1 (1-2) cm. No donor-site major complications, but mild oral discomfort in the first week after graft harvesting, were reported in 39 (83%) patients. After the second stage, complications were reported in nine (19.2%) patients, meatal stenosis in five and fistula in four. The reported success rate was 80.9%.

DISCUSSION

Reconstruction of previously failed hypospadias is a challenge owing to local tissue scarring and a paucity of adjacent healthy tissue. In this study, the LMG was used in two-stage redo hypospadias repair after previous repair failure. In the present study, a success rate of 80.9% was reported after the second stage. According to this study and the published series, harvesting the LMG is associated with minimal immediate donor-site complications and no long-term morbidity. Another advantage of the LMG is easy harvesting with effortlessly reachable tongue in comparison with the buccal mucosa that is deep and requires application of a mouth retractor.

CONCLUSIONS

Two-stage LMG urethroplasty is a reliable procedure for salvage urethroplasty. Lingual mucosal graft harvesting is easy, with minor oral complications.

microRNA expression profiles of scar and normal tissue from patients with posterior urethral stricture caused by pelvic fracture urethral distraction defects

Pelvic fracture urethral distraction defect (PFUDD) seriously affects the quality of life of patients. At present, there are few effective drug treatments available for PFUDD-induced urethral stricture, which is associated with fibrosis and scar formation in urethra lumen. Emerging evidence suggests that microRNAs (miRNAs/miRs) may be involved in the regulation of fibrosis, and analysis of miRNA expression profiles in urethral scar and normal urethra tissues may therefore benefit the discovery of novel treatments for urethral stricture with micro invasive procedures. In the present study, miRNA sequencing and quantitative polymerase chain reaction (qPCR) validation using paired scar and normal tissues from patients with PFUDD, and functional analysis of the miRNAs involved in the fibrosis associated signaling pathway was performed. A total of 94 differentially expressed miRNAs were identified in the scar tissue of patients with PFUDD. Among them, 26 miRNAs had significantly altered expression in the scar tissue compared with the normal tissue from the same patient. qPCR validation confirmed that miR-129-5p was overexpressed in scar tissue. The TGF-β pathway-associated functions of a total of 5 miRNAs (hsa-miR-129-5p, hsa-miR-135a-5p, hsa-miR-363-3p, hsa-miR-6720-3p and hsa-miR-9-5p) were further analyzed, as well as their key molecular targets and functional mechanisms in signaling regulation. To conclude the miRNA sequencing indicated a significantly altered expression of hsa-miR-129-5p, hsa-miR-135a-5p, hsa-miR-363-3p, hsa-miR-6720-3p and hsa-miR-9-5p in patients with PFUDD. These miRNAs and their potential target genes were associated with fibrosis in several diseases, and the data from the present study may help explore potential miRNA targets for future precision treatments for urethral stricture.

Lingual mucosal graft two-stage Bracka technique for redo hypospadias repair

Objectives

To report our initial experience in redo hypospadias repair with a lingual mucosal graft (LMG) using a two-stage Bracka technique.

Patients and methods

This study was prospectively conducted and included 26 patients with hypospadias with failed previous repairs. All the patients had a LMG using a two-stage Bracka technique. In the first stage, the harvested LMG, from the ventro-lateral surface of the tongue, was implanted in a well-prepared vascularised bed in the ventral aspect of the penis. After 6 months, tubularisation of the well-taken graft was completed. Tunica vaginalis or a dartos flap was used as second-layer coverage of the neourethra. Success was defined as acceptable aesthetic and functional outcomes without any additional surgical interventions.

Results

The mean (SD) patient age was 5.15 (1.6) years. The mean (SD) LMG length was 3.82 (0.9) cm and the width was 1.5 (0.5) cm. The mean (SD) number of previous repairs was 2.76 (1.1). The mean (SD) follow-up was 12 (2) months. Donor-site complications included: pain in all patients, with a pain score of >3 on the visual analogue pain scale (0–10) in 10 (38%); and speech problems in 19 (73%). First-stage complications were graft loss (n = 2) and contracture (n = 1). The second stage was completed in 23 patients resulting in the following significant complications: meatal stenosis plus fistula (n = 2), breakdown (n = 1). Successful hypospadias repair was achieved in 77% (20/26) of the patients.

Conclusion

Lingual mucosa is a reliable and versatile graft material in the armamentarium of two-stage Bracka hypospadias repair with the merits of easy harvesting and minor donor-site complications.

Application of Wnt Pathway Inhibitor Delivering Scaffold for Inhibiting Fibrosis in Urethra Strictures: In Vitro and in Vivo Study

Objective: To evaluate the mechanical property and biocompatibility of the Wnt pathway inhibitor (ICG-001) delivering collagen/poly(l-lactide-co-caprolactone) (P(LLA-CL)) scaffold for urethroplasty, and also the feasibility of inhibiting the extracellular matrix (ECM) expression in vitro and in vivo. Methods: ICG-001 (1 mg (2 mM)) was loaded into a (P(LLA-CL)) scaffold with the co-axial electrospinning technique. The characteristics of the mechanical property and drug release fashion of scaffolds were tested with a mechanical testing machine (Instron) and high-performance liquid chromatography (HPLC). Rabbit bladder epithelial cells and the dermal fibroblasts were isolated by enzymatic digestion method. (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay) and scanning electron microscopy (SEM) were used to evaluate the viability and proliferation of the cells on the scaffolds. Fibrolasts treated with TGF-β1 and ICG-001 released medium from scaffolds were used to evaluate the anti-fibrosis effect through immunofluorescence, real time PCR and western blot. Urethrography and histology were used to evaluate the efficacy of urethral implantation. Results: The scaffold delivering ICG-001 was fabricated, the fiber diameter and mechanical strength of scaffolds with inhibitor were comparable with the non-drug scaffold. The SEM and MTT assay showed no toxic effect of ICG-001 to the proliferation of epithelial cells on the collagen/P(LLA-CL) scaffold with ICG-001. After treatment with culture medium released from the drug-delivering scaffold, the expression of Collagen type 1, 3 and fibronectin of fibroblasts could be inhibited significantly at the mRNA and protein levels. In the results of urethrography, urethral strictures and fistulas were found in the rabbits treated with non-ICG-001 delivering scaffolds, but all the rabbits treated with ICG-001-delivering scaffolds showed wide caliber in urethras. Histology results showed less collagen but more smooth muscle and thicker epithelium in urethras repaired with ICG-001 delivering scaffolds. Conclusion: After loading with the Wnt signal pathway inhibitor ICG-001, the Collagen/P(LLA-CL) scaffold could facilitate a decrease in the ECM deposition of fibroblasts. The ICG-001 delivering Collagen/P(LLA-CL) nanofibrous scaffold seeded with epithelial cells has the potential to be a promising substitute material for urethroplasty. Longer follow-up study in larger animals is needed in the future.

Urethral 'cripples': two-staged procedures

PURPOSE OF REVIEW

To review the current literature on staged procedures in patients with previous urethral interventions ('urethral cripples').

RECENT FINDINGS

Five studies published during the past 18 months could be identified, the majority with short-term follow-up and small patient numbers. Four studies investigated the outcome after redo surgery in hypospadias patients, one study after urethral stricture disease.

SUMMARY

The few data published suggest acceptable complication rate and success rate for surgical outcome. Long-term and prospective data with special respect to sexual function, patient satisfaction, and quality of life are still lacking.