Single piece artificial urinary sphincter for secondary incontinence following successful repair of post traumatic urethral injury.

Post traumatic urethral injury is uncommon in children. The management of this condition is dependent on the severity of injury. Initial suprapubic cystostomy with delayed repair is the conventional treatment. Successful reconstruction of urethral injury may be followed by urethral stricture, incontinence, impotence, and retrograde ejaculation. Successful repair of post traumatic urethral injury followed by secondary incontinence in children has not been well addressed in literature. We report the management of one such child, with satisfactory outcome with implantation of a new model of single piece artificial urinary sphincter in the bulbar urethra by perineal approach.

INTRODUCTION

Incontinence, following repair of post traumatic urethral disruption, is a complication which can be difficult to treat. The mechanism of incontinence in this situation may be related to the original trauma or follow transpubic surgery and damage to nerves or sphincter. The management of secondary incontinence in children following repair of urethral injuries is difficult and challenging. Although a few studies have reported the long-term outcome of urethral injury in children, the incidence and management of incontinence following repair has not been well-reported.[1] We report a teenager who was brought to us with disabling secondary incontinence of 10 year duration following successful repair of urethral injury.

CASE REPORT

A 14-year-old boy came to us with incontinence after post pelvic fracture-related urethral injury repair. He had suffered urethral injury in a road traffic accident 10-years-ago followed by staged urethral reconstruction. At the end of few months of urinary diversion, he had undergone urethral repair using abdominoperineal approach. Ten years following surgery, he was able to pass urine but he continued to dribble all the time. He had been on several modalities of medical management with no benefit. On examination, he had an abdominal and perineal scar of previous operation and deformed and scarred penile skin due to chronic use of condom catheter, leading to some tourniquet effect.

The renal function tests, urine routine, microscopy, and culture were normal. Ultrasound of the urinary tract revealed normal upper tracts and no post void residue. The post-operative micturating cystourethrogram (MCU) done 10 years after repair, revealed a normal capacity bladder. There was urinary leak at 200 ml, no vesicoureteric reflux, absence of urethral stricture, and no post void residual urine. Voiding cystometry showed that he had normal capacity stable bladder with leak at 200 ml and detrusor pressures in normal range [Figure 1]. On cystoscopy, the anastomotic site at posterior urethra at the junction of bulbar and prostatic urethra was identified and admitted 9F resectoscope with ease. The bladder mucosa was normal and the bladder neck was not closing adequately on withdrawal of the cystoscope into urethra.

Figure 1

Conventional cystometry demonstrating subnormal detrusor pressure

After detailed evaluation, he was put on conservative management for incontinence with a trial of anticholinergics, clean intermittent catheterization, pelvic floor exercises, and timed voiding for 6 weeks. The urinary leak persisted without any improvement. The child had suffered for 10 years and was constantly on diapers or using condom catheters with significant scarring of the penis and no relief with medical management.

Surgical technique

The child was prepared for bulbar placement of the cuff by the perineal approach and placed in lithotomy position. A 12 F Foley catheter was placed. A midline perineal incision was made and bulbocavernosus muscle was dissected from the bulbar urethra by blunt dissection. Subdartos pouch was created through a separate inguinal incision for pump placement. The bulbar urethra was mobilized for cuff placement. We used the ZSI 375 (Zephyr surgical implants, Switzerland) artificial urinary sphincter [Figure 2]. The cuff was placed around the bulbar urethra with the urethral catheter in situ and secured with a nonabsorbable suture [Figure 3]. The urethral catheter was removed after filling the bladder and ZSI 375 was activated. The functioning of the sphincter device was checked and the position of the spring in the pump unit calibrated to the desired midline position. The pump was placed in subdartos pouch and fixed. The sphincter was deactivated and urethral catheter placed again.

Figure 2

Single piece artificial urinary sphincter ZSI 375 (Zephyr surgical implants, Switzerland)

Figure 3

Cuff implanted around bulbar urethra by the perineal approach

The child was discharged the next day with the catheter in situ. Six weeks later, the catheter was removed and the device was activated. The father and the child were taught how to deflate the cuff. The child was observed for 24 hrs in the Hospital till he was comfortable in using the device. One year after surgery, the child now deflates the cuff on feeling the urge to micturate and passes urine in good stream, voids to completion with no incontinence.

DISCUSSION

Post traumatic urethral injuries in children following pelvic fracture are difficult to manage. The use of artificial urinary sphincter (AUS) for post-traumatic sphincter incontinence has not been evaluated extensively. Scott et al., first described the use of artificial urinary sphincter for treating urinary incontinence in 1973.[2] There are only a few reports in literature of AUS implantation at the bladder neck for sphincter incontinence resulting from pelvic fracture related urethral and bladder neck injury in children. All the patients achieved continence initially, but there was a high rate of erosion of the AUS in these studies.

Ashley et al., reported five children with longitudinal tear at bladder neck and posterior urethral distraction injury who underwent AUS placement at the bladder neck.[3] The AUS was implanted at the bladder neck instead of bulbar urethra for the fear of jeopardizing the vascularity of the anastomotic site at the posterior urethra. All five had erosion of the device in a mean time of 3 years (range 6 months to 8 years). In another series, Routh et al., reported three children with post-traumatic bladder neck laceration extending through the prostatic urethra into the bulbar urethra. The AUS was placed around the bulbar urethra and all of them had AUS erosion between 3 and 8 years after placement.[4]

The authors of both these studies believe that the high, almost 100% erosion rates noted in patients who underwent previous bladder neck and urethral reconstruction is probably due to aberrant or inadequate urethral vasculature following the surgical procedure. They have not recommended AUS placement in posttraumatic pediatric pelvis and instead have suggested for continent catheterizable urinary diversion in children with complete urinary incontinence secondary to traumatic posterior urethral disruption and concurrent bladder neck incompetence.

The continent catheterizable stoma based on Mitrofanoff's principle may be a better approach; however, it has its own problems. The continent catheterizable stoma after bladder neck surgery versus artificial urethral sphincter implantation in the bulbar urethra for this problem may continue to be debatable due to the high complication rates of the former procedure too.[56]

In our patient, the surgeon had succeeded in restoring the continuity of urethra without any residual stricture but secondary incontinence had left him dependent on catheter drainage for 10 years. We considered a trial of medical management, which failed to provide any relief. The option of continent diversion was discussed with family, which was not acceptable to them. After considerable discussion with family around the risk of erosion, we finally decided to implant a new model of artificial urinary sphincter not described previously in literature.

The single piece artificial urinary sphincter made by (Zephyr surgical implants, Switzerland) is elegantly designed and easier to implant. A cystoscope was used during implantation to confirm occlusion of the urethra adequately on spontaneous inflation of the cuff. The single piece design also makes the implantation easier and risk of mechanical and infectious complication less. The implantation of the cuff in the bulbar urethra, away from the site of previous surgery allowed easy dissection and preservation of vascularity of the urethra.

In our patient, the follow up is only 1 year and the previously reported children have had erosion as the major complication leading to failure of surgery during later years. In case of unfortunate complication of urethral erosion, a continent diversion could still be offered as the last resort. Since the entire surgery in the implantation of the artificial sphincter is outside the abdomen, continent diversion in the following years would not be a problem. The adjustable cuff fits all sizes of urethra and is molded in a circular form so there are less chances of stress fracture due to creasing. The issued pressure of ZSI 375 can be readjusted after the procedure. The long term follow-up of this device and its performance remains to be seen. At this stage, it appears to be an attractive solution to this disabling complication and may once again bring a new ray of hope to this problem by having continence with natural voiding rather than the recommended continent diversion.

CONCLUSION

Urinary incontinence after repair of post traumatic urethral disruption in children can be a disabling complication continuing in adolescent and adult life. Although, it has been recommended that they should undergo continent diversion based on the poor outcome of artificial sphincter, the arrival of a new model and appropriate age of the child made us consider implantation of artificial sphincter with satisfactory result at this stage of follow-up. Continent urinary diversion will remain the last resort in failed cases.