Objective: The objective is to test if the injection of a bulking agent in the anal canal is superior to sphincter training with biofeedback in the treatment of anal incontinence.
Background: Anal incontinence is traditionally treated with conservative measures, such as pads and constipating medicine. If this fails, sphincter training with biofeedback is often offered before more advanced surgical procedures are considered. The injection of a bulking agent in the anal canal is a relatively new and promising treatment option.
Methods: In a randomized, controlled, evaluator-blinded trial, 126 adult patients with anal incontinence were randomly assigned to a transanal, submucosal injection of 4 x 1 mL of dextranomer in hyaluronic acid or to sphincter training with biofeedback. The primary outcome was severity of incontinence, evaluated by St Mark's score for incontinence (0 = continence to 24 = complete incontinence) assessed at 2 years after the start of treatment. A mixed models analysis was applied.
Results: Of the 126 participants, 64 patients were randomly assigned to anal injections, and among them the mean St Mark's score improved from 12.9 (95% CI: 11.8-14.0) at baseline to 8.3 (95% CI: 6.7-9.8) at the end of follow up. Among the 62 patients who were assigned to sphincter training with biofeedback, there was a corresponding improvement in St Mark's score from 12.6 (95% CI: 11.4-13.8) to 7.2 (95% CI: 7.2-8.8). Comparisons of St Mark's scores between the groups showed no differences in effect between treatments.
Conclusion: The efficacy of anal injections and biofeedback in treating anal incontinence did not differ in this randomized, single-blinded, controlled trial.