Clinical efficacy of transcutaneous tibial nerve stimulation (TTNS) versus sham therapy (part I) and TTNS versus percutaneous tibial nerve stimulation (PTNS) (part II) on the short term in children with the idiopathic overactive bladder syndrome: protocol for part I of the twofold double-blinded randomized controlled TaPaS trial

Background Transcutaneous tibial nerve stimulation (TTNS) and percutaneous tibial nerve stimulation (PTNS) are effective and safe therapies for overactive bladder (OAB) syndrome in adults. However, few randomized sham-controlled trials have been conducted in a pediatric population. To our knowledge, both therapies never have been compared in children. Aim The aim of the complete study is twofold: (1) to assess the efficacy of TTNS therapy on bladder symptoms after 12 weeks of treatment in a pediatric population with idiopathic overactive bladder syndrome (iOAB) and/or nocturnal enuresis (part I) and (2) to assess the effect of TTNS compared to PTNS (part II). In this article, we aim to present the protocol of the first part of the TaPaS trial (TTNS, PTNS, sham therapy). Methods Part I of the TaPaS trial is set up as a single-center randomized-controlled trial. Children, aged from 5 to 12 years with iOAB and/or nocturnal enuresis, are assigned to two groups by computer-generated randomization: TTNS therapy (intervention) and sham therapy (control). The primary outcome is the percentage difference in average voided volume (AVV) between baseline and after 12 weeks of treatment. Secondary endpoints are the percentage difference in supervoid volumes, number of urinary incontinence episodes/24 h and in voiding frequency, the difference in parent reported outcomes between baseline and after 12 weeks of treatment, and the duration of clinical response. Discussion We hypothesize that TTNS is a non-inferior treatment for iOAB in children compared to PTNS therapy. Since literature is inconclusive about the efficacy of TTNS in a pediatric population, a sham-controlled RCT on TTNS will be conducted (part I). A protocol for a prospective randomized sham-controlled trial has been developed. Enrolment has started in November 2018. Study completion of part I is expected by August 2021.