Effects of a magnetic field on pelvic floor muscle function in women with stress urinary incontinence

Context Magnetic fields have been found to affect neuromuscular function. Objective To study the effect of a magnetic field on measurements of urethral function in women with stress urinary incontinence. Design Observational comparative study. Setting Consecutive patients in a continence center. Patients or other participants Twenty-six consecutive women with diagnosis of stress urinary incontinence (SUI). Evaluation History and physical examination, neurologic exam, urethrocystoscopy, urodynamic testing with water-filling cystometry, urethral profilometry at rest, during coughing, and during coughing while performing a levator ani contraction (knack maneuver). Intervention The same urodynamic procedures were performed again after the subjects were asked to step on specifically designed magnets (magnetic cushion device). Statistical analysis Two-tailed student t test. Main outcome measures Urethral pressure at rest, during coughing, and during coughing while performing a levator ani contraction. Results Mean age was 58.3 years (range: 36-81), mean parity 2.8 (range: 0-8). The urodynamic parameters measured without and with the use of the magnetic cushion device were not found to be different except for the knack maneuver. The pressure in the urethra during the knack maneuver while the subjects were stepping on the magnetic device was significantly higher than the 1 obtained without the magnetic field. Conclusion In our patient population, a magnetic field increases the efficacy of voluntary levator ani contractions.