127. Does reduction in number of injection sites of abobotulinumtoxinA impact efficacy in neurogenic detrusor overactivity (NDO) in the spinal cord‒injured (SCI) rat model?

Abstract

Spinal cord injury (SCI) induces plasticity within neural pathways innervating the lower urinary tract (LUT), with the recruitment of nociceptive “silent” C-fibers leading to the development of an abnormal autonomic micturition reflex and emergence of neurogenic detrusor overactivity (NDO), thereby greatly compromising bladder filling during the micturition cycle. In SCI patients, botulinum toxin A has been evaluated for the treatment of refractory NDO and have been reported to decrease urinary incontinence frequency and maximum intravesical pressure while increasing bladder capacity and compliance Onabotulinum (Ona) toxin A intradetrusor injections is registered as a second-line treatment to treat NDO in humans. Injection protocol remains variable among clinical studies. Hovever approved Ona label recommends 30 injection points in the bladder wall. The main objective of this study was to determine the effect of reducing the number of injection sites by comparing the effect of 4 versus 8 injection sites with abobotulinum toxin A (aboBoNTA) in the SCI rat, a relevant model of NDO METHODS Experimental design Nineteen days post-SCI, rats received intradetrusor injections in 4 or 8 sites of saline or aboBoNTA 22.5U. Two days after injections, effect of aboBoNTA on urodynamic clinically relevant parameters was determined by analysis of variance test versus aggregated saline groups (ASG). Four experimental groups were considered: saline (NaCl 0.9%) 4 sites (12.5µl total volume, n=12; S-4sites), saline 8 sites (25µl total volume, n=11; S-8sites), aboBoNTA 4 sites (12.5µl total volume, 5.6U per site, n=20; aboBoNTA-4sites) and aboBoNTA 8 sites (25µl total volume, 2.8U per site, n=20; aboBoNTA-8sites).