Correlation of urodynamic results and urethral coaptation with success after transurethral collagen injection

We correlated preoperative urodynamic and intraoperative endoscopic findings with initial improvement, single collagen injection effectiveness for intrinsic sphincter deficiency (ISD), and long-term improvement following transurethral collagen injection for stress urinary incontinence (SUI).

Since 1993, 79 patients have been treated with transurethral collagen injection by the same urologist. Of these patients, intraoperative photographs of urothelial coaptation immediately after injection were available in 67 patients: 35 women with ISD, 24 men with incontinence, primarily following prostatectomy, and 8 children with neurogenic bladder. Urothelial coaptation was described as snug, fair, or poor. Preoperative Valsalva leak point pressure (VLPP), detrusor instability, impaired bladder compliance, bladder neck appearance, urothelial scarring, and degree of coaptation were correlated with both initial and long-term improvement. Initial improvement was compared with long-term improvement.

Initial improvement was experienced by 85% of all the subjects (86%) of the women, 80% of the men, and 100% of the children with a neurogenic bladder condition). Overall, 31% of patients had long-term improvement after a mean follow-up of 2.2 years, including 43% of the women, 13% of the men, and 33% of the children. The patients underwent a mean of 1.5 (1 to 4) collagen injections. There was a significant correlation between degree of coaptation and initial improvement (P = 0.003), but not with long-term improvement. There was no correlation between VLPP detrusor instability, impaired compliance, bladder neck appearance, or urethral scarring and initial improvement. There was no correlation between any parameter and long-term improvement or between initial and long-term improvement.

Initial endoscopic appearance following collagen injection predicted initial, but not long-term, improvement after one collagen injection. Initial improvement was high in both men and women but decreased considerably over time, more so in men, and was not significantly correlated with long-term success. Urodynamic and endoscopic findings do not predict long-term success following collagen injection.