Effectiveness and Cost-effectiveness of Sacral Neuromodulation in Patients With Idiopathic Slow-transit Constipation

Rationale: Previous reviews showed that the evidence regarding the effectiveness of sacral neuromodulation (SNM) in patients with therapy-resistant, idiopathic (slow-transit) constipation is of suboptimal quality. Furthermore, there is no estimate of costs and cost-effectiveness in this patient group. Objective: The main objective of this study is to assess the effectiveness of SNM compared to personalized conservative treatment (PCT), in patients with idiopathic slow-transit constipation who are refractory to conservative treatment. The secondary objectives are assessing the 1) costs, 2) cost-effectiveness and 3) budget-impact of SNM compared to PCT. Hypothesis: Based on previous research we hypothesize that SNM will be more effective than PCT in terms of a significantly higher proportion of patients having treatment success at 6 months. Study design: An open-label pragmatic randomized controlled trial (RCT) combined with a prospective cohort study. Study population: Adolescent (14-17 years) and adult (18-80 years) patients with idiopathic slow-transit constipation refractory to conservative treatment. Intervention: The intervention is SNM, a minimally invasive surgical procedure consisting of two phases. In the screening phase an electrode is inserted near the third sacral nerve and connected to an external stimulator. If the screening phase is successful (average defecation frequency (DF) ≥3 a week), the electrode is connected to a pacemaker that is implanted in the buttocks of the patient. If not successful, patients receive conservative treatment. The control intervention is PCT. This is the best and least invasive alternative to SNM. PCT consists of medication and/or retrograde colonic irrigation. Main study parameters/endpoints: The primary outcome is success at 6 months, defined as an average DF of ≥3 a week according to a 3-week defecation diary. Secondary outcomes are straining, sense of incomplete evacuation, constipation severity, fatigue, constipa