Assessment of the effects of autologous muscle-derived cell injections on urethral sphincter morphometry using 3D/4D ultrasound.

PURPOSE: The primary objective was to evaluate the effect of autologous muscle-derived cell (AMDC) injections on the urethral sphincter morphometry compared to placebo injections. Secondary aims were to explore the reduction of stress incontinence episode frequency (IEF) and factors associated with the efficacy of AMDC. METHODS: This prospective randomized-controlled study compared the urethral sphincter volumes of participants who had received either an intra-sphincteric injection of 4 cc AMDC in injection media or 4 cc placebo solution, using a transperineal 3D/4D ultrasound at baseline and at 12 months. The reduction of stress IEF on 3-day bladder diary and potential predictors at baseline for response to AMDC were assessed. RESULTS: Fifty-eight participants were included in the study. Compared to baseline, the mean total and external sphincter volumes increased significantly in both groups (respectively, p = 0.001 and p < 0.001 in the AMDC group, p < 0.001 and p = 0.005 in the placebo group) at 12 months. Both groups showed a significant reduction of stress IEF compared to baseline (p = 0.03 and p ≤ 0.001 for AMDC and placebo groups, respectively). There were no between-group differences regarding total and external sphincter volumes and reduction of stress IEF. A longer urethral length (p ≤ 0.001) and a larger external sphincter volume (p ≤ 0.05) were significantly associated with lower stress IEF. CONCLUSION: Significant increases of sphincter volumes as well as reduction of stress IEF occurred among the AMDC and placebo injection groups with no between-group differences at 12 months. A longer urethral length and a larger external sphincter volume at baseline were identified as potential predictors of AMDC injection response.