The aim of this study is to evaluate the durability of collagen injection (CI) using serial 3-dimensional (3D) transvaginal ultrasound (US) in women with sufficient improvement of stress urinary incontinence (SUI) symptoms not requiring additional treatment.Methods
After the institutional review board approval, a retrospective review of prospectively followed patients who underwent CI was conducted. Eligible patients received 3 or less consecutive CI for SUI with no reinjection afterward during the follow-up period and had a minimum follow-up of 1 year from the last CI. Serial 3D US was obtained for collagen volume and configuration at baseline (6–8 weeks postoperatively) and approximately every 12 months thereafter as clinically indicated.Results
Of 191 eligible patients from 1/99 to 6/11, 67 (35%) met the inclusion criteria. The mean age was 67 years (42–90 years) with mean follow-up from the time of last CI at 43 months (12–149 months). A total of 283 three-dimensional US were performed, with the mean of 4 (2–11) per patient. The mean number of injections was 1.4 (1–3) with a mean injected volume at 5.8 mL (2–18 mL). The volume retention rate compared with the baseline volume was 84% (12%-100%), with a decrease in mean collagen volumes between the baseline and last follow-up visit (3.2 vs 2.7 mL; P = 0.008). Collagen volume decreased by a mean of 0.11 mL for each year past the final injection (P = 0.0015) by mixed-effect model analysis.Conclusions
Although believed to be nondurable, CI was found to be objectively stable over time by transvaginal 3D US in a subset of women with durably improved SUI symptoms.