Percutaneous Tibial Nerve Stimulation Effects on Detrusor Overactivity Incontinence are Not Due to a Placebo Effect: A Randomized, Double-Blind, Placebo Controlled Trial

Purpose: This is a prospective, double-blind, placebo controlled study, based on an original placebo technique, performed to evaluate the efficacy of percutaneous tibial nerve stimulation in female patients with detrusor overactivity incontinence. Materials and Methods: A total of 35 female patients presenting with detrusor overactivity incontinence that did not respond to antimuscarinic therapy were randomly assigned to percutaneous tibial nerve stimulation or to a control group. The percutaneous tibial nerve stimulation group (18 patients) was treated with 12 percutaneous tibial nerve stimulation sessions. The control group (17 patients) received an original placebo treatment using a 34 gauge needle placed in the medial part of the gastrocnemius muscle. The sessions lasted for 30 minutes and were performed 3 times weekly as percutaneous tibial nerve stimulation sessions. All patients were evaluated with bladder diaries as well as quality of life scores before and after treatment. Patients showing a reduction in urge incontinence episodes greater than 50% were considered responders. Results: Some patients (1 in the percutaneous tibial nerve stimulation group and 2 in the placebo group) did not complete the study for reasons not related to the technique. Of 17 patients in the percutaneous tibial nerve stimulation group 12 (71%) and of 15 in placebo group 0 were considered responders according to the previously reported definition (p < 0.001). Improvement in the number of incontinence episodes, number of voids, voided volume and incontinence quality of life score were statistically significant in the percutaneous tibial nerve stimulation group but not in the placebo group. Conclusions: Percutaneous tibial nerve stimulation can be considered an effective treatment for detrusor overactivity incontinence with 71% of patients considered responders, while none of those treated with placebo was considered a responder. The relevance of a placebo effect seems to be negligible in this patient population.