Eddy current density for non-invasive treatment system for urinary incontinence using Functional Continuous Magnetic Stimulator (FCMS)

The authors have devised a non-invasive, painless treatment system composed of a Functional Continuous Magnetic Stimulator (FCMS) and a large saddle type coil for urinary incontinence, especially stress incontinence and urge incontinence. First, the authors assumed the current density to apply to the objective stimulation region by general electrical stimulation. As a result, the absolute current density |Je| assumed by calculation was 12.7 /spl mu/A/mm/sup 2/. Second, they have developed a saddle type coil for the FCMS which can be used practically in most hospital and stimulate continuously for 15 minutes. The coil has a cooling function to maintain the coil temperature to use the coil efficiently safely between 20/spl deg/C-25/spl deg/C. The size of the saddle type coil is 21 cm long, 12 cm wide and 3 cm thick. The most suitable region for urinary incontinence is from the anus to perineum and the saddle type coil can fit on this region. In experiments with dogs, we confirmed that the urethral pressure increased when the circumference of the perineum received Continuous Magnetic Stimulation (CMS) with 720 /spl mu/s pulse width (180 /spl mu/s risetime), 10 Hz frequency and about 500 V capacitor charge voltage. This result suggest that magnetic stimulation is effective as a stress urinary incontinence and urge urinary incontinence therapy. The specifications of the FCMS are 2 kW maximum electrical power consumption, 800 V maximum stimulation intensity, 720 /spl mu/s pulse width (180 /spl mu/s risetime), 5-30 Hz frequency. The frequency is selected to treat urge incontinence between 5 and 10 Hz and to treat stress incontinence between 25 and 30 Hz.