Long-term clinical value of urethral sphincter injection of onabotulinumtoxinA for patients with acontractile bladder

Objective: To determine the long-term objective and subjective outcomes of urethral sphincter injection of onabotulinumtoxinA (OnaBoNT/A) in patients with acontractile bladder. Materials and methods: We enrolled patients with acontractile bladder who received OnaBoNT/A injection in the urethral sphincter between May 2003 and April 2009. The objective outcome was assessed based on the changes in postvoid residual urine (PVR) volume and the necessity of clean intermittent catheterization (CIC). Abstinence from CIC with a decrease in PVR volume by more than 75% was defined as success. A decrease in PVR volume between 75% and 25% was defined as improved. The treatment was defined as failed if the decrease in PVR volume is less than 25%. Subjective outcome was assessed by the Clinical Global Impression of Improvement (CGI-I) questionnaire. CGI-I scores of 1 (very much improved) and 2 (much improved) were considered clinically significant improvement. Results: The study included 26 patients (20 women and six men). Among these patients, nine (35%) had successful treatment, 12 (46%) had some clinical improvement, and the treatment failed in five patients (19%). In the 10 patients who needed CIC, one discontinued CIC and two reduced the frequency of CIC after OnaBoNT/A injection. Nine patients received repeated injections. With a median follow-up of 32.8 months, only 33% patients reported clinically significant improvement. Conclusion: OnaBoNT/A injection into the urethral sphincter improved bladder emptying for patients with acontractile bladder. However, only one-third of the patients obtained relevant subjective long-term benefit.