Collagen injections for genuine stress urinary incontinence: patient selection and durability.

The questions of patient selection parameters and durability of response in the use of collagen injections for genuine stress incontinence are addressed. A total of 181 women with a mean age of 64 years (range 26-94) underwent collagen injections for urethral incompetence. Treatment outcome was determined by a change in individual incontinence grades before and after injection. Of the 181 women 42 (23%) are cured, 94 (52%) are improved and 45 (25%) failed. Follow-up in the successful patients, either cured or improved, was a mean of 21 months (range 4-69) after their last collagen injection. No difference in outcome was seen in relation to patient age or pretreatment grade of incontinence. Of the 30 patients with bladder instability, 18 (60%) had a favorable outcome. No significant difference in outcome was seen in patients with or without hypermobility (P = 0.2889). Patients with type III incontinence required the largest amount of collagen for a successful outcome. The persistence of continence in 78 patients who were cured for at least 2 months were plotted on a Kaplan-Meier survival curve. The probability of remaining dry without additional collagen was 72% at 1 year, 57% at 2 years and 45% at 3 years. It was concluded that, collagen injection into the urethra is a safe and well-tolerated procedure. Pretreatment bladder instability may be an adverse factor. Patients with or without hypermobility had equal benefit. Long-term durability was seen. If deterioration occurred repeat collagen injections restored success. The current literature is reviewed and the use of collagen relative to other treatments is discussed.