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

Cystoscopic Guided Laser Cauterization in a Dog with Complete Y-Type Urethral Duplication

Duplication of the urethra is a rare congenital malformation. A 14-month-old, sexually intact, male, Lagotto dog with complete Y-type urethral duplication was subjected to accessory urethra treatment for cystoscopic guided laser cauterization, with a 10-Watt diode laser with 550-micron fiber and 2.3 Fr outer diameter. The laser cauterization, that was repeated every 14 days for a total of three times, was performed by inserting the instrument from the accessory urethra outlet in the perianal area until it could be seen by the urethroscope, inside the ischial urethra. Nevertheless, this technique that proved to be non-invasive, less expensive than surgery, of short duration, and safe, did not allow the complete closure of the abnormal urethral tract. Therefore, the subsequent surgical removal of the accessory urethra was carried out. To the authors' knowledge this is the first report on the use of cystoscopic guided diode laser cauterization for accessory urethra treatment.

A Novel Approach to Penile Augmentation Urethroplasty Using Buccal Mucosa and Amniotic Membrane: A Pilot Study in a Rabbit Model

OBJECTIVE

To evaluate and compare the success of amniotic membrane (AM) and buccal mucosa (BM) grafts and simultaneous use of both in penile augmentation urethroplasty in rabbits.

MATERIALS AND METHODS

A total of 12 New Zealand rabbits were divided into 3 groups by grafting style: Group 1 (AM), Group 2 (BM), and Group 3 (simultaneous use of BM and AM). In all animals, a standardized urethral defect was created. BM and AM were obtained from the rabbits. Solely AM grafts were affixed to the defects in Group 1, solely BM grafts were affixed to the urethral defects in Group 2, and simultaneous AM + BM grafts were affixed in Group 3. At 4 and 8 weeks, the penises were subject to histological assessment of subepithelial fibrosis, epithelial transformation, and inflammatory reaction.

RESULTS

Stenosis was detected in none of the groups. A dehiscence was developed in one rabbit in Group 1 and a fistula was developed in one rabbit in Group 2. After 4 weeks, minimal subepithelial fibrosis and inflammatory reaction were observed in Group 2, while subepithelial fibrosis was not in Groups 3. After 8 weeks, subepithelial connective tissue proliferation was moderate in Group 2, at both 4th and 8th weeks in Group 2. After 8 weeks, the best epithelial transformations were observed in Group 3.

CONCLUSION

In an animal model, the simultaneous use of AM and BM grafts following acute urethral injury may be feasible for penile augmentation urethroplasty. Further study is needed.

Buccal mucosal urethroplasty for treatment of recurrent hemospermia in a stallion

CASE

Description-An 11-year-old Quarter Horse stallion was admitted for intermittent hemospermia of 4 years' duration.

CLINICAL FINDINGS

A linear vertical defect had been detected endoscopically following multiple episodes of hemospermia on the caudodorsal convex surface of the urethra at the level of the ischial arch.

TREATMENT AND OUTCOME

When sexual rest alone did not result in complete healing of the urethral defect, a subischial urethrotomy and buccal mucosal urethroplasty were performed. The surgical site healed without complication. Four months of sexual rest was recommended after surgery. Repeat endoscopy at 4 months allowed inspection of the urethral graft site. Following endoscopic examination, resumption of semen collection was recommended on the basis of the apparent healing at the urethral defect site. Hemospermia did not reoccur following surgical repair.

CLINICAL RELEVANCE

Buccal mucosal urethroplasty resulted in a favorable outcome in a stallion with recurrent hemospermia. Buccal mucosal urethroplasty may be a useful surgical option in stallions that have hemospermia secondary to a urethral defect and do not heal with sexual rest alone.

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.

A comparison of free skin graft, fascia lata, alloderm, bovine pericardium and primary repair in urethrocutaneous fistulas without diversion: an experimental study

The purpose of this study is to compare primary repair procedure with those that use bio-concordant materials in the treatment of urethrocutaneous fistula. Twenty-five New Zealand rabbits were randomly placed into five groups (primary repair, free graft, allograft fascia lata, alloderm and bovine pericardium repair groups). A single dose of 20 mg/kg of ceftriaxon was applied intramuscularly as a prophylactic dose. Urethrocutaneous fistula was formed on midpenile level. Later, while primary repair was applied in one group, repair with free grafts and with other bio-concordant materials were performed in other groups. Urinary diversion was not used in any of the rabbits. The macroscopic observation was evaluated with urethrography obtained 21 days after the operation and then the rabbits were sacrificed. A total point was obtained by awarding a point to each good parameter in the histopathological evaluation and all the groups were compared. The urethrographic findings and macroscopic examinations were normal in all groups. In histopathological examinations, ranging from the best to worst results, bovine pericardium group (8 points) had a better total score than primary repair group (7 points), allograft fascia lata group (7 points) and alloderm group (7 points). The free graft group had the worst total point (6 points). Bio-concordant materials can be used in urethrocutaneous fistula repair as an alternative to primary repair or to the grafts obtained from body tissues.