Objective: To assess the short- and medium-term efficacy of periurethral collagen injection in women with urethral sphincter incompetence and to determine if urodynamic variables can elucidate the mechanism of action.
Patients and methods: Sixty women (mean age 64 years, range 20-90) with genuine stress incontinence received periurethral collagen injections under local anaesthesia; 55 had undergone previous continence surgery. A total of three injection sessions were allowed. Subjective and urodynamic assessments were obtained at 1, 3, 6, 12 and 24 months after injection to evaluate success and long-term effects of collagen.
Results: Subjective success rates were 86% at 3 months, 77% at 12 months and 68% at 24 months. Objective cure rates were 61% at 3 months, 54% at 12 months and 48% at 24 months. Low urethral pressures and decreased bladder neck mobility did not affect the outcome. Collagen injections significantly increased stress maximum urethral closure pressures and functional urethral length; increase in the latter and clinical assessment of bulking at the time of injection appeared to predict medium-term success. There were some minor early complications and none in the medium-term.
Conclusions: Periurethral collagen injections continued to be effective at the 2-year follow-up, although there was a time-dependent decline. In comparison with more complicated procedures used in patients with previous failed continence surgery, periurethral collagen injection is a simple, acceptable, day case procedure which improves the quality of life in physically fit or frail patients, with few complications.