BACKGROUND: : Sacral nerve stimulation has been reported as an effective treatment for constipation. OBJECTIVE: : This study aimed to evaluate the therapeutic efficacy of permanent sacral nerve stimulation on the treatment of idiopathic constipation resistant to medical and behavioral management over a median follow-up period of 25.6 (range, 6-96) months. DESIGN: : A retrospective review of a prospectively maintained institutional review board-approved database was performed. SETTING: : The study was performed at 2 tertiary-care European institutions with expertise in sacral nerve stimulation. PATIENTS: : Patients were considered eligible if they had had symptoms for at least 1 year and if conservative treatment had failed. INTERVENTION: : Patients were tested by percutaneous nerve evaluation before the procedure. If this evaluation was successful, patients underwent sacral nerve therapy with an implanted device. MAIN OUTCOME MEASURE: : Patients were evaluated by means of a bowel function diary and the Wexner constipation score. RESULTS: : A total of 48 consecutive patients (39 females, median age 50.0 years (range, 17-79 years) entered the study. Twenty-three patients were implanted with a permanent stimulator. On an intention-to-treat basis, only 14 of 48 patients (29.2%) met the definition of a successful outcome at the latest follow-up period (median, 25.6 (range, 6-96) months). The mean Wexner score decreased from 20.2 (SD 3.6) at baseline to 5.8 (SD 4.1) at the latest follow-up examination (p