A Randomized Controlled Trial of Instillation Protocols Prior to Intradetrusor OnabotulinumtoxinA

Achieving adequate pain relief is crucial for intradetrusor onabotulinumtoxinA treatments for idiopathic overactive bladder in office settings. The objective of this study was to determine whether buffered lidocaine bladder instillation provides better pain control than standard lidocaine prior to intradetrusor onabotulinumtoxinA injections.

We conducted a prospective, double-blind, randomized controlled trial comparing two protocols. The standard protocol used a pre-procedure instillation of 50 ml of 1% lidocaine and 50 ml of 0.9% saline. The buffered lidocaine protocol used 50 ml of 1% lidocaine, 45 ml of 0.9% saline, and 5 ml of 8.4% sodium bicarbonate. Both protocols were administered 20 min before onabotulinumtoxinA injections. Female patients with a primary diagnosis of idiopathic overactive bladder were randomized. The primary outcome was procedural pain using a visual analog scale (VAS) measured in millimeters, with secondary outcomes of patient satisfaction and willingness to repeat the procedure.

Of the 76 patients enrolled, 38 were randomized to each group. Data were analyzed for 37 patients in the buffered lidocaine group, and 36 in the standard lidocaine group. Both groups had comparable baseline characteristics. There was no difference in median pain measured by VAS between the buffered (16 [9-40]) and standard (25 [15-55]) protocols (p = 0.21). The buffered group reported a higher, though not statistically significant, satisfaction rate (68% vs 39%, p = 0.08).

Intradetrusor onabotulinumtoxinA injections are generally well tolerated among women with idiopathic overactive bladder. No difference was found between protocols, suggesting that buffered lidocaine instillation may not improve pain control among women with idiopathic overactive bladder, although we had insufficient power to detect a difference of the observed magnitude.