Intradetrusor onabotulinumtoxinA injections for refractory neurogenic detrusor overactivity incontinence: do we need urodynamic investigation for outcome assessment?

Objective To evaluate if urinary continence after intradetrusor onabotulinumtoxinA injections is sufficient for appropriate outcome assessment or if urodynamic investigation (UDI) is needed. Patients and Methods A consecutive series of 148 patients undergoing intradetrusor onabotulinumtoxinA injections for refractory neurogenic detrusor overactivity (NDO) incontinence were prospectively evaluated. Patients underwent UDI prior and 6 weeks after onabotulinumtoxinA injections. Primary outcome was the prevalence of maximum storage detrusor pressure >40 cmH2O in continent patients 6 weeks after treatment. Secondary outcomes were treatment effects on other clinical and video-urodynamic parameters. Results 6 weeks after intradetrusor onabotulinumtoxinA injections, 98 (66%) of the 148 patients with NDO incontinence became continent. Of these patients, 18 (18%, confidence interval 12-27%) had a maximum storage detrusor pressure >40cmH2O. Gender, underlying neurological disorder and high storage detrusor pressures prior to treatment seem to increase the risk for poor urodynamic outcomes. Conclusions Urinary continence is not sufficient for outcome assessment after intradetrusor onabotulinumtoxinA injections, since high intravesical pressures threatening the upper urinary tract might be missed in a relevant percentage of continent patients. Therefore, we strongly recommend UDI as a routine part of the follow-up. This article is protected by copyright. All rights reserved.