Effect of the intravesical resiniferatoxin instillation evaluated by the ice provocative urodynamic study

Abstract

STUDY DESIGN: Prospective urodynamic investigation before and after intravesical resiniferatoxin instillation treatment. OBJECTIVE: To evaluate the effectiveness of intravesical resiniferatoxin instillation for the treatment of neurogenic detrusor overactivity (NDO), using conventional and ice provocative urodynamic studies to monitor the activity of the unmyelinated C-fiber. SETTING: Spinal Cord Injury Unit, Yonsei Rehabilitation Hospital, Seoul, Korea. METHODS: A measure of 100 ml of resiniferatoxin solution, at a concentration of 100 nM diluted in 10% ethanol, was intravesically instilled into the bladder of 15 spinal cord injury patients with NDO. Conventional and ice provocative urodynamic studies were performed to evaluate the change in the involuntary detrusor activity, reflex volume, maximal bladder capacity, compliance, maximal detrusor pressure and reflex volume ratio 7 days before and 30 days after the instillation. RESULTS: Before the intravesical resiniferatoxin instillation, all patients exhibited NDO in both the conventional and ice provocative urodynamic studies, with a mean reflex volume ratio of 0.45+/-0.22. There was no significant change in the maximal bladder capacity, compliance and maximal detrusor pressure at the follow-up urodynamic study, but the reflex volume ratio was significantly increased (P<0.05) after the intravesical resiniferatoxin instillation. Among the 15 patients, three (20%) showed complete and nine (60%) partial suppression of the unmyelinated C-fiber activities. CONCLUSION: Intravesical resiniferatoxin instillation was partially controlled by the unmyelinated C-fiber activities, which were estimated by an ice provocative urodynamic study. Therefore, further studies on the optimal dosage and accurate indications for resiniferatoxin instillation are required.