RECONSTRUCTIVE UROLOGY

Artificial Urinary Sphincters Placed After Posterior Urethral Distraction Injuries in Children are at Risk for Erosion
Ashley RA, Husmann DA
Department of Urology, Mayo Clinic, Rochester, Minnesota
J Urol. 2007, 178: 1813-1815

• Purpose: Management for posterior urethral disruption and concurrent bladder neck incompetence is controversial. Some groups recommend treatment with a Mitrofanoff catheterizable stoma, while others advocate urethral reconstruction with delayed placement of an artificial urinary sphincter. We report our experience with the latter strategy.
• Materials and Methods: We reviewed the records of all patients with the above injury who were treated with end-to-end urethroplasty followed by delayed bladder neck artificial urinary sphincter placement from 1986 to 2006.
• Results: Five patients had videourodynamic evidence of bladder neck incompetence coexisting with traumatic posterior urethral disruption. The etiology of bladder neck incompetence in all 5 patients was a known longitudinal tear through the bladder neck that occurred at the time of trauma. Each patient underwent end-to-end urethroplasty. Six to 12 months later the patients had persistent incontinence. Bladder function and urethral patency were documented by urodynamic, radiographic and endoscopic studies. A bladder neck artificial urinary sphincter was subsequently placed. Each operation was technically demanding due to fibrosis in the pelvis and around the bladder neck. All patients were initially continent but erosion of the artificial urinary sphincter into the bladder neck in 4, and the bladder neck and rectum in 1 occurred at a mean of 3 years (range 6 months to 8 years).
• Conclusions: Placement of a bladder neck artificial urinary sphincter for managing urinary incontinence due to concurrent posterior urethral disruption and bladder neck incompetence is difficult and it risks delayed erosion. In this patient population we would strongly consider urinary diversion with a Mitrofanoff catheterizable stoma.
  
  
• Editorial Comment
  Stress urinary incontinence as a result of urethral injury occurs in approximately 10% of pelvic trauma cases. Urinary stress incontinence usually only occurs in those boys with posterior urethral disruption and an additional rabdosphincter injury. The primarily reconstructive approach with the placement of a suprapubic catheter secures healing but does not give any guarantee for functionality. Two possibilities occur after the removal of the transurethral catheter: incontinence or stricture. The incidence of urinary stress incontinence is lower compared to stricture development. The two major questions that occur are, when and which surgical approach to offer the pediatric patient, who suffers from stress urinary incontinence. Ashley & Husmann reported in their group of five patients to place an artificial sphincter 6-12 months after the reconstructive approach, which might be still too early regarding the extensive surgical approach and the not ideal position for the cuff of an AMS 800. In addition, the treated males were on average 11-year-old, who are still growing. This is most probably due to a consequence of one or all of the three mentioned arguments’ failure.
  Because of surgery for the after effects of the injury, the approach is sometimes invasive resulting in scars and poor vascularization. Secondly, especially the cuff around the bladder neck / prostate might cause not only obstruction but – due to the poor tissue quality with reduced vascularization – result in erosion in those patients in the follow-up because they are still growing. This might be an explanation of the average explantation time of 3 years (6 months to 6 years) after the implantation.
  If an artificial urinary sphincter is at all considered in children and adults, it should be placed through the penoscrotal approach to the bulbar urethra (1). It is easier to access and the tissue is in most cases untouched, which supports the healing and makes the whole approach less invasive. In the follow-up, an age-adapted cuff size exchange is easier to be performed. Some might argue that the smallest cuff might still be too big for the bulbar urethra, but local tissue or acellular matrices can be placed in-between the urethra and the cuff. This tissue or matrix protects the urethra and the cuff, avoiding erosions. The authors are correct that the approach to perform the Mitrofanoff catheterizable stoma in these patients is a very elegant way, too and an artificial urinary sphincter with an age-adapted cuff size is the second best choice beside the Mitrofanoff catheterizable stoma.

Reference
1. Sievert KD: Fast implantation of an artificial urethral sphincter through a peno-scrotal approach. Eur Urol. 2007; Video Journal, Abst V9, Volume 13.2.

Dr. Karl-Dietrich Sievert &
Dr. Arnulf Stenzl
Department of Urology
Eberhard-Karls-University Tuebingen
Tuebingen, Germany
E-mail: Arnulf.Stenzl@med.uni-tuebingen.de