Urodynamic assessment during intravesical infusion of capsaicin for the treatment of refractory detrusor hyperreflexia

Purpose: Parameters to predict outcome and the urodynamic effects during infusion of capsaicin, seem not to have been assessed in patients with chronic cord injury. We monitored bladder activity urodynamically during infusion of high dosage of capsaicin. Material and methods: Thirty patients, 18 women and 12 men (average age 29 years, range 20-59 years), suffering from chronic spinal myelopathy, who presented a refractory detrusor hyperreflexia: were studied. They received saline solution containing 10(-3) M capsaicin at a flow rate of 2 ml min(-1) for 15 min (total volume 30 c.c.). The detrusor activity was monitored by a real-time cystometrogram during infusion and 15 min after the end, of the infusion itself. New filling cystometrograms were recorded after 30 days and after 6 months. Results: We obtained a clinical and significant urodynamic improvement in 15 of the 30 patients (50%). confirming that intravesical capsaicin may represent a therapeutic option for a selected group of patients suffering from refractory detrusor hyperreflexia due to chronic spinal upper motor neuron lesion. Best results were observed in patients who showed, during the infusion of capsaicin, early uninhibited bladder contractions which disappeared within 10-12 min from the beginning of the infusion (desensitisation). The patients of this group presented a significant increase of mean cystomanometric capacity after 6 months (from 190.7 to 396.7 mi). No significant clinical or urodynamic improvement was observed in the group of patients in whom uninhibited activity of detrusor was recorded for all the time of infusion. Conclusion: Our results support the idea of a major complexity of spinal reflex in paraplegic patients and may offer a clue to explain the failure of therapy with capsaicin. The present results support a new approach in the treatment of detrusor hyperreflexia. The ideal dosage and treatment interval are not at present established and further studies are needed to explain substantial differences in the outcome according to different urodynamic responses.