 All patients will be contacted for a structured telephone interview follow-up at a time-point varying between 18 to 78 months after the study termination. A questionnaire was used to assess present pain level, medication, use of the SCS system, side effects and global satisfaction. Patients will also be asked whether they would have participated if they had known the outcome in advance, and if they would recommend a trial of SCS treatment to someone else with similar gastrointestinal problems. 