Urodynamic Effect of Intravesical Resiniferatoxin in Patients with Neurogenic Detrusor Overactivity of Spinal Origin: Results of a Double-Blind Randomized Placebo-Controlled Trial

Abstract

Objectives: To access by a placebo-controlled randomized clinical trial the effect of intravesical resiniferatoxin on the urodynamic parameters of patients with neurogenic detrusor overactivity (NDO) of spinal origin. Methods: Twenty eight patients with spinal NDO were randomised to receive intravesically 50 nM resiniferatoxin dissolved in 10% ethanol in saline (RTX group) or only the vehicle solution (placebo group). Filling cystometries were obtained in each patient at 1 month and 1 week before and at 1 and 3 months after treatment. In a visual analog scale patients were asked to estimate the discomfort induced by treatment. Patients were also persuaded to fill a micturition chart during the 3 days preceding each cystometry. Results: The RTX and placebo groups were homogeneous in what respects the volume to first involuntary detrusor contraction (FDC, 143 ± 95 ml and 115 ± 58 ml, respectively, p = 0.3) and maximal cystometric capacity (MCC, 189 ± 99 ml and 198 ± 111 ml, respectively, p = 0.8). At the end of the study, mean FDC and MCC in the RTX group, 184 ± 93 ml and 314 ± 135 ml, respectively were significantly higher than in the placebo group, 115 ± 61 ml ( p = 0.03) and 204 ± 92 ml ( p = 0.02). In the visual analogue scale discomfort caused by treatment was similar. Only 10 patients in the RTX group and 6 patients in the placebo group completed adequately the micturition chart. Mean frequency and urinary incontinence decreased significantly only in the RTX group. Conclusions: Intravesical RTX is effective in increasing bladder capacity in spinal NDO patients. Such increment might contribute to decrease urinary frequency and incontinence of these patients.