The overall objective of this study is to determine the effect of posterior tibial nerve stimulation (PTNS) on children with constipation due to pelvic floor dyssynergia. Our main hypothesis is that PTNS effectively treats children with constipation secondary to pelvic floor dyssynergia through modulation of anorectal function. We will perform a single-center, randomized controlled pilot study comparing PTNS to sham stimulation in children with constipation secondary to pelvic floor dyssynergia.

Constipation affects up to 30% of children in population-based studies and 15% of children with constipation will continue to have symptoms despite years of aggressive medical treatment. Pelvic floor dyssynergia, which involves abnormal coordination of pelvic floor muscles during defecation, is a common finding during anorectal manometry testing for children with refractory constipation. Treatment options for children with constipation refractory to medical treatment are limited and generally invasive. Thus, there is an urgent need for the identification and evaluation of non-invasive treatments for constipation refractory to medical treatment. We have established, through research at our institution, that electrical stimulation delivered via gastric electrical stimulator and sacral nerve stimulator is feasible and effective in the treatment of gastrointestinal disease. There is new evidence that posterior tibial nerve stimulation (PTNS), a non-invasive method of delivering electrical stimulation, can be effective in the treatment of adults with constipation and fecal incontinence. Our long-term goal is to identify and evaluate novel non-invasive treatment options for children with constipation refractory to medical treatment.

The overall objective of this study is to determine the effect of PTNS on children with constipation due to pelvic floor dyssynergia. Our main hypothesis is that PTNS effectively treats children with constipation secondary to pelvic floor dyssynergia through modulation of anorectal function. We plan to objectively test our main hypothesis and attain the objective of this application by pursuing the following specific aims:

AIM 1: Determine the efficacy of PTNS in the treatment of children with constipation due to pelvic floor dyssynergia. The working hypothesis is that PTNS will lead to improvement in validated measures of constipation severity.

AIM 2: Determine the effects of PTNS on anorectal function. The working hypothesis is that PTNS will lead to improvement in pelvic floor dyssynergia.

The expected outcome of Aim 1 is demonstration that PTNS is effective in decreasing the symptom severity of children with constipation due to pelvic floor dyssynergia. Aim 2 will show that PTNS improves symptoms by modulating anorectal function. Establishing that PTNS is an effective treatment option for children with constipation due to pelvic floor dyssynergia will have a significant positive impact on a population of children for which management is challenging and current therapeutic options are limited. Determining the mechanism by which PTNS acts will further our understanding of the effect of electrical stimulation on the human body and could lead to identification of other applications of therapeutic electrical stimulation.

Inclusion Criteria:

• Patients 8-18 years of age
• Diagnosis of constipation due to pelvic floor dyssynergia
• Scheduled to start pelvic floor biofeedback therapy.

Exclusion Criteria:

- Prior surgery for constipation (colonic resection, cecostomy, Malone appendicostomy, sacral nerve stimulator implantation, etc.)