Randomized controlled multisite trial of injected bulking agents for women with intrinsic sphincter deficiency: mid-urethral injection of Zuidex via the Implacer versus proximal urethral injection of Contigen cystoscopically.

OBJECTIVES: To determine whether Zuidex using a non-cystoscopy mid-urethral injection technique produces as good a result (i.e. was not inferior) as Contigen injected endoscopically at the bladder neck in the treatment of urinary stress incontinence secondary to intrinsic sphincter deficiency in adult women.

METHODS: A prospective 2:1 randomized trial of mid-urethral injections of Zuidex-Implacer vs proximal urethral cystoscopic injections of Contigen was performed in 344 women with intrinsic sphincter deficiency at 23 North American sites, and followed up for >1 year from last treatment.

RESULTS: Outcomes at 12 months from last treatment failed to demonstrate that mid-urethral injected Zuidex was equivalent to cystoscopically injected Contigen in primary and secondary outcome variables. The primary outcome, the proportion of women who achieved a 50% reduction in urinary leakage on provocation testing, was achieved in 84% of Contigen-treated women vs 65% of Zuidex-treated women.

CONCLUSIONS: Confounding multiple variables inherent in the study design make a detailed analysis of study outcomes difficult.