Long-Term Sacral Magnetic Stimulation for Refractory Stress Urinary Incontinence

Abstract

ObjectiveTo evaluate the effects of sacral magnetic stimulation (SMS) on functional and urodynamic improvement in patients with refractory stress urinary incontinence (SUI). DesignA sham-controlled, double-blind, parallel study design with a 4.5-month follow-up. SettingA tertiary hospital. ParticipantsWomen (age, 45–75y) with SUI refractory to first-line management (N=34) were allocated to either an experimental (n=20) group or a sham (n=14) group. InterventionsThe SMS protocol consisted of 5-Hz, 20-minute treatments administered over the bilateral third sacral roots, with the intensity set at approximately 70% of the maximal output, for 12 consecutive weekdays. Main Outcome MeasuresUrodynamic assessments and 2 life stress questionnaires, namely, the Urge-Urinary Distress Inventory (U-UDI) and the Overactive Bladder Questionnaire (OAB-q), were administered pre- and post-SMS intervention. We administered the U-UDI (primary outcome measure) and the OAB-q at 3-week intervals during the follow-up period until 18 weeks after the final intervention. ResultsThe experimental group exhibited significant improvements in both U-UDI and OAB-q scores postintervention (P=.011–.014) and at follow-up visits (P<.001–.007) compared with the sham group. In addition, significant increases in bladder capacity, urethral functional length, and the pressure transmission ratio (P=.009–.033) were noted postintervention. Multivariate regression analysis revealed that patients with more severe symptoms benefited more from SMS. A poorer baseline U-UDI score and a shorter urethral functional length were associated with a greater response to SMS. ConclusionsOur observations of a greater response to SMS in patients with more severe SUI than in those with mild symptoms, as well as the long-term benefits of the treatment, confirm the efficacy of SMS in treating SUI.