Efficacy of polydimethylsiloxane injection to the bladder neck and leaking diverting stoma for urinary continence

Achieving urinary continence is a major goal in the treatment of patients with bladder exstrophy/epispadias, spinal dysraphism and other urological disorders. Endoscopic injection of bulking materials is an evolving, minimally invasive procedure that provides an attractive alternative to open bladder surgery to increase outlet resistance. We evaluated the efficacy of bladder outlet (bladder neck and diverting stoma) polydimethylsiloxane injection (BOMI) to achieve continence in children.

We retrospectively reviewed the continence status of 33 patients prior to and following BOMI for urinary incontinence. The variables evaluated as predictors of success were underlying disease, ambulatory status, voiding status, bladder capacity, type and time from previous bladder neck reconstruction, anticholinergic treatment, injection site, amount of polydimethylsiloxane used, detrusor leak point pressure and immediate or delayed clean intermittent catheterization. Improvement was considered a 2-fold increase in the dry interval or 4 hours between bladder emptying in patients on clean intermittent catheterization and a 2-fold decrease in the number of absorbent pads needed.

Between 1998 and 2002, 25 male and 8 female patients 4 to 19 years old (mean age 12.4 +/- 3.9) underwent 42 BOMIs for incontinence. Mean followup was 13 +/- 9 months (range 3 to 42). Incontinence was via the urethra in 28 cases and via a diverting stoma in the remaining 5. Of the 28 patients with leakage via the urethra none were cured, 12 (42%) were improved and 16 (58%) had no change in continence status. However, 3 of the 5 inpatients (60%) with leakage via a diverting stoma were cured. No perioperative complications were recorded. Injecting to a diverting stoma was the only factor found to be predictive of success. Extrusion of polydimethylsiloxane during the procedure was the only factor predictive of failure (3 of 3 cases or 100%). New onset dilatation of the collecting system was noted in 2 patients and all had improved continence following injection.

Injection to the bladder neck did not result in any cure and had a low improvement rate of 42%. BOMI is a good therapeutic option for patients with leakage from a diverting stoma. Although no perioperative complications were recorded, 2 patients had new dilatation of the upper tract on ultrasound. Hence, long-term followup is warranted.