Long-term sacral magnetic stimulation for refractory stress urinary incontinence.

ABSTRACT

OBJECTIVE: To evaluate the effects of sacral magnetic stimulation (SMS) on functional and urodynamic improvement in patients with refractory stress urinary incontinence (SUI). DESIGN: A sham-controlled, double-blind, parallel study design with a 4.5-month follow-up. SETTING: A tertiary hospital. PARTICIPANTS: Women (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. INTERVENTIONS: The 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 MEASURES: Urodynamic 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. RESULTS: The 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. CONCLUSIONS: Our 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.