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, constipation specific and generic (health-related) quality of life ((HR)QOL), and costs at 6 months. Furthermore, cost-effectiveness and budget-impact will be estimated.


Eligibility Criteria:
Inclusion Criteria:

* An average defecation frequency (DF) of \<3 per week based on a 3-week defecation diary (patient-reported)
* Meet at least one other criterion of the Rome-IV criteria for idiopathic constipation based on the 3-week defecation diary (1)
* Refractory to conservative treatment
* Age: 14-80 years
* Slow-transit constipation

  (1) Rome-IV criteria for idiopathic constipation:
* Straining during ≥25% of defecations
* Lumpy or hard stools in ≥25% of defecations
* Sensation of incomplete evacuation for ≥25% of defecations
* Sensation of anorectal obstruction/blockage for ≥25% of defecations
* Manual manoeuvres to facilitate ≥25% of defecations

Exclusion Criteria:

* Obstructed outlet syndrome (objectified by defeacography)
* Irritable bowel syndrome (Rome-IV criteria for irritable bowel syndrome)
* Congenital or organic bowel pathology
* Rectal prolapse
* Anatomical limitations preventing placement of an electrode
* Skin and perineal disease with risk of infection
* Previous large bowel/rectal surgery
* Stoma
* Coexisting neurological disease
* Significant psychological co-morbidity as assessed subjectively by the investigator
* Being or attempting to become pregnant during study follow-up