Hypospadias repair by bladder mucosal graft: an initial report

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.

Use of Bipedicled Dorsal Penile Flap With Z Release Incision: A New Option in Redo Hypospadias Surgery

OBJECTIVE

To solve the challenge in redo hypospadias surgery, we tried to use a bipedicled dorsal penile flap with a Z release incision in failed hypospadias cases and reported the outcome.

MATERIALS AND METHODS

Thirty male children with 3 or 4 previous unsuccessful hypospadias surgeries were included in our study. Our technique was done after at least 6 months from the last surgery. A flap of the dorsal penile skin was preserved and the skin lateral to the flap was dissected on each side. A small opening was done in the dartos proximal to flap. The glans was withdrawn through this opening with a ventral transposition of the flap. Z-plasty was used to compensate for the deficient dorsal skin; the Z-plasty had 3 limbs and all were made of equal length.

RESULTS

The mean age of the patients was 5.4 ± 1.8 years and the mean follow-up was 2.1 ± 0.7 years. The technique was successful in 80%. Reoperation was required in 3 cases; all cases were managed using a 2-stage buccal mucosal graft. A small fistula at the coronal level developed in 2 cases but closed spontaneously within 1 month. All patients were voiding well and had a vertically oriented meatus at the tip of the glans and satisfactory cosmetic results.

CONCLUSION

Repair of failed hypospadias using a bipedicled dorsal penile skin flap with Z release incision is a safe and simple procedure offering high success rates.

Penile urethra replacement with autologous cell-seeded tubularized collagen matrices

Acellular collagen matrices have been used as an onlay material for urethral reconstruction. However, cell-seeded matrices have been recommended for tubularized urethral repairs. In this study we investigated whether long segmental penile urethral replacement using autologous cell-seeded tubularized collagen-based matrix is feasible. Autologous bladder epithelial and smooth muscle cells from nine male rabbits were grown and seeded onto preconfigured tubular matrices constructed from decellularized bladder matrices obtained from lamina propria. The entire anterior penile urethra was resected in 15 rabbits. Urethroplasties were performed with tubularized matrices seeded with cells in nine animals, and with matrices without cells in six. Serial urethrograms were performed at 1, 3 and 6 months. Retrieved urethral tissues were analysed using histo- and immunohistochemistry, western blot analyses and organ bath studies. The urethrograms showed that animals implanted with cell-seeded matrices maintained a wide urethral calibre without strictures. In contrast, the urethras with unseeded scaffolds collapsed and developed strictures. Histologically, a transitional cell layer surrounded by muscle was observed in the cell-seeded constructs. The epithelial and smooth muscle phenotypes were confirmed with AE1/AE3 and α-actin antibodies. Organ bath studies of the neourethras confirmed both physiological contractility and the presence of neurotransmitters. Tubularized collagen matrices seeded with autologous cells can be used successfully for long segmental penile urethra replacement, while implantation of tubularized collagen matrices without cells leads to poor tissue development and stricture formation. The cell-seeded collagen matrices are able to form new tissue, which is histologically similar to native urethra.

COMPLETE REPAIR OF BLADDER EXSTROPHY: MANAGEMENT OF RESULTANT HYPOSPADIAS

PURPOSE

In our hands complete primary repair (CPR) of bladder exstrophy results in hypospadias in two-thirds of boys. To our knowledge hypospadias repair following CPR of bladder exstrophy has not been reported previously. We report our experience with hypospadias repair following CPR of bladder exstrophy.

MATERIALS AND METHODS

A total of 22 boys with bladder exstrophy underwent CPR using Mitchell's technique between November 1998 and January 2002. The procedure resulted in hypospadias in 15 boys (68%). The site of the meatus was distal penile in 5 patients, mid penile in 3 and proximal penile in 7. Hypospadias repair was performed in all 15 boys. The 5 patients with distal penile hypospadias underwent repair consisting of Thiersch-Duplay urethroplasty with dorsal incision in 3 and tubularized vertical island flap with glanular tunnel in 2. All patients with mid (3) or proximal (7) penile hypospadias underwent Mustarde repair with glanular tunnel.

RESULTS

Followup ranged from 6 to 18 months (median 13). The Thiersch-Duplay procedure with dorsal incision resulted in fistula/stenosis in 2 of 3 boys. None of the remaining 12 boys with tubularized penile flap urethroplasty (tubularized vertical island flap or Mustarde) with glanular tunneling had development of fistula or stenosis. Complete degloving of the penis and penile skin redistribution were not necessary with the Mustarde technique.

CONCLUSIONS

Thiersch-Duplay urethroplasty with dorsal incision does not seem to be a good option for hypospadias repair following CPR of bladder exstrophy. The use of penile skin as a tubularized flap with glanular tunneling seems to yield excellent functional/cosmetic results.

Concepts in the surgical technique of one-stage hypospadias correction

OBJECTIVE

To report on a single-stage technique for hypospadias repair based on the combination of several features of established methods and to emphasize the importance of identifying and excising the chordee that is almost always present in the tissues proximal to the urethral opening to ensure the complete correction of this deformity.

PATIENTS AND METHODS

Over a 3-year period, 84 boys (age range from 8 months to 14 years) underwent a single-stage repair of proximal hypospadias. Chordee was corrected by excising fibrotic tissue representing the atretic corpus spongiosum proximal to the urethral opening. The neourethra was constructed using the epithelium distal to the urethral opening and part of the dorsal prepuce.

RESULTS

Satisfactory results were obtained in 79 patients with a single procedure. Only five patients had fistulae and of these, four were closed successfully during the same hospital stay.

CONCLUSION

Proximal hypospadias can be corrected using the single-stage technique described, with satisfactory results in most cases. Fistulae are uncommon and can be closed by a primary procedure performed in the post-operative period.

Bladder mucosal grafts for severe hypospadias: a successful technique

Free grafts of bladder mucosa may be used to bridge long urethral defects in the repair of hypospadias. Strictures, which occur commonly at the proximal anastomotic site with the native meatus and where the bladder mucosa is exposed on the glans, have limited the use of the procedure. We have found that draining the proximal anastomosis prevents most strictures. When the distal most portion of the neourethra is formed from the skin of the ventral penile shaft and glans, no bladder mucosa is exposed and meatal stricture is thereby avoided.

Simplified postoperative management of hypospadias repair

OBJECTIVE

To assess the effect of simplified postoperative management of hypospadias repair in an outpatient setting.

METHODS

The records of 162 boys were reviewed who underwent hypospadias repair by the following techniques: meatal-based flap (72), free skin graft (54), two-stage repair (21), and bladder mucosal graft (15). Urinary diversion was provided by open catheter drainage in the latter three groups, and a simple wrap penile dressing was used in all patients. With the exception of the bladder mucosal graft technique, all procedures were performed as outpatients.

RESULTS

Complications requiring a second surgical procedure occurred in 28 patients (17%). No patient required rehospitalization during the postoperative period.

CONCLUSIONS

These results compare favorably to previously reported series utilizing traditional postoperative techniques.

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

Autologous bladder mucosa was used as a free graft for complex urethral reconstruction in 95 male patients, ranging in age from 1 to 21 years. Primary indications for surgery include previous failed hypospadias repair in 68 cases, primary hypospadias in 11, bladder exstrophy/epispadias complex in 10 and others in 6. Patients were divided into 3 groups based on the configuration of the bladder mucosa replacement. Group 1 (37 patients) underwent complete urethral replacement to the tip of the glans. Group 2 (16 patients) underwent placement of a bladder mucosa onlay patch graft. Group 3 (42 patients) underwent a combined repair using tubularized bladder mucosa proximally and either a pedicled preputial tube (6), free preputial or penile skin tube (13), local glandular skin flaps (15), or intact glandular urethra or tubularized urethral plate (8) distally to avoid a terminal segment of bladder mucosa. All patients were followed for a mean of 3.4 years (range 6 months to 8 years). An overall good functional and cosmetic result was eventually achieved in 81 patients (85%). However, 63 patients (66%) required between 1 and 9 (mean 2.7) additional procedures to treat complications before achieving a good result. The most common complications were meatal stenosis and/or prolapse. Meatal problems were significantly more common in group 1 (68%) than in those who underwent a patch or combined procedure (12 and 36%, respectively). Although bladder mucosa provides an excellent and readily available material for urethral substitution in these challenging cases, the urologist should be aware of the significant incidence of postoperative problems and their management. The high incidence of meatal problems suggests that bladder mucosa should not be incorporated as a circumferential terminal urethral segment.

Transpubic-perineal urethral reconstruction in boys using a substitution graft

A combined transpubic-perineal 1-stage approach was used for urethral replacement and proximal urethral repair in 6 boys: 4 were treated for a long proximal urethral stricture secondary to trauma and 2 with urethral atresia underwent replacement of the entire anterior urethra. All patients underwent a urethral substitution graft of either skin or bladder mucosa. Followup ranged from 2 to 8 years with all patients continent.

Free bladder mucosal graft biology: unique engraftment characteristics in rabbits

To study the biology of bladder mucosal grafts we developed an animal model using New Zealand white male rabbits. A 25 x 9 mm. segment of bladder mucosa was harvested and tubularized over an 8F catheter using 7-zero polyglactin sutures. An equivalent portion of rabbit urethra was then excised and the graft was anastomosed to this defect in an end-to-end fashion. A urethral catheter was left in place to provide bladder drainage and to stent the anastomosis. Animals were sacrificed on postoperative days 1 to 90. India ink was injected into the aorta at sacrifice to visualize the microvasculature. All 59 specimens were stained with hematoxylin and eosin, and studied using light microscopy. Our results demonstrated vascular ingrowth at 72 hours. Between postoperative days 8 and 10 healthy viable epithelium first bridged the entire urethral defect. By postoperative day 12 the epithelial lining was complete. A poor outcome was observed in all animals whose stents were removed early. We conclude that the biology of bladder mucosal grafts is unique in that the graft initially undergoes partial degeneration followed by regeneration. Of concern are the results of those animals whose stents were removed early. In all such cases a poor outcome was observed.

Posterior urethroplasty with tubularized bladder mucosal graft

Surgical management of long strictures of the posterior urethra is difficult and there is no concrete method that guarantees excellent results. The use of bladder mucosa has become established in the 1980s as treatment for anterior urethral reconstruction in hypospadias repair. We report 2 difficult cases (multioperations) of membranous urethral strictures treated with free tubularized bladder mucosal grafts with good initial results.

Complications of bladder mucosal graft

A bladder mucosal graft for urethral reconstruction was performed on 79 patients who had complicated conditions in which local penile or preputial skin was not available. The major and minor complication rates for this procedure were 15.2 and 43 per cent, respectively, the latter representing mucosal glanular protrusion obviated by a technical alteration. Given the difficulty of these cases these complication rates are deemed acceptable in such patients.