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Abstract Background: Extracorporeal magnetic innervation (ExMI) is a new technology used for pelvic muscle strengthening for the treatment of stress urinary incontinence. We explored whether this new technology is effective for patients with urge incontinence, as well as those with stress urinary incontinence.
Methods: We studied 20 patients with urge incontinence and 17 patients with stress urinary incontinence. The Neocontrol system (Neotonus Inc., Marietta, GA) was used. Treatment sessions were for 20 min, twice a week for 8 weeks. Evaluations were performed by bladder diaries, one-hour pad weight testing, quality-of-life surveys and urodynamic studies.
Results: Of the urge incontinence cases, five patients were cured (25.0%), 12 patients improved (60.0%) and three patients did not show any improvement (15.0%). Leak episodes per day reduced from 5.6 times to 1.9 times at 8 weeks (P < 0.05). Eight patients with urge incontinence recurred within 24 weeks after the last treatment (47.1%). Of the stress incontinence cases, nine patients were cured (52.9%), seven patients improved (41.1%) and one patient did not show any improvement (6%). In one-hour pad weight testing, the mean pad weight reduced from 7.9 g to 1.9 g at 8 weeks (P < 0.05). Three patients returned to the baseline values within 24 weeks after the last treatment (17.6%). No side-effects were experienced by any of the patients.
Conclusion: Although the results for urge incontinence were less effective than for stress urinary incontinence, ExMI therapy offers a new option for urge incontinence as well as stress urinary incontinence.
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From October 2001 to November 2002, a total of 37 patients with urinary incontinence were enrolled in this study. Written informed consent was obtained from the patients to participate in this study. Seventeen women with a mean age of 60.1 ± 12.6 years old (range 29–80) had stress incontinence and three men and 17 women with a mean age of 68.5 ± 14.2 years old (range 29–85) had urge incontinence. The duration of symptoms on stress and urge incontinence ranged from 0.5 to 20 years (median 2.5), and from 1 to 25 years (median 4 years), respectively. Stress incontinence patients were type I in 10 patients, type II in six patients and type III in one patient (Table 1).
Table 1. Clinical characteristics of patients with urge and stress incontinence
| ||Stress incontinence||Urge incontinence|
|Number of patients||17||20|
|Mean age (years; mean, range)||60.1 (29–80||68.5 (29–8)|
|Male : Female||0 : 17||3 : 17|
|One-hour pad test (g; mean, range)||7.9 (0.9-22.6)||–|
|Parity (median, range)||2 (1–3)||2 (0–3)|
|Duration (years; median, range)||2.5 (0.5–20)||4 (1–25)|
|Leakage number (mean, range)||3.3 (7.7–6)||3.8 (1–16)|
| I||10|| |
| II|| 6|| |
| III|| 1|| |
Patients were excluded if they were younger than 20 years old. Patients with a cardiac pacemaker or other implanted metallic device were also excluded, as were actual or suspected pregnant women. The pretreatment evaluations included a 5-day bladder diary, urodynamic study and a validated quality-of-life survey (I-QOL; Visual analog scale, VAS).8,9 When using the visual analog scale, patients scored their present continence condition on a 10-point analog scale (0, continence; 10, complete incontinence). The I-QOL data was scored with a range of possible scores from 22 to 110 (representing 22 questions with answers scored between 1 and 5). The conversion used a formula that put the total scores on a 0–100 scale, which were then rounded to one decimal place. All stress incontinence patients completed one-hour pad weight testing to measure the severity of leakage.
During the treatment, the patient is positioned in a chair provided with the Neocontrol system (Neotonus Inc., Marietta, GA). Treatment sessions were for 20 min, twice a week for 8 weeks. The frequency of the pulsed magnetic field was 10 Hz, intermittently for 10 min, followed by a rest interval of 2 min and the second treatment was at 50 Hz intermittently for 10 min. This frequency and mode of stimulation have been programmed in the machine.
Interval measures included a 5-day bladder diary, and the quality-of-life survey was repeated every 2 weeks. The voided volumes, the number of leaks per day and the voided number of patients per day were recorded in the bladder diary. A one-hour pad test was repeated every 4 weeks. A urodynamic study was performed before and one week after the treatment. At 4 and 24 weeks after the last treatment, the bladder diary, quality-of-life survey and one-hour pad test were repeated. The clinical outcome for patients with urge incontinence was considered cured when there was no incontinence and improved when the frequency of incontinence decreased by more than 50%. For patients with stress incontinence, the clinical outcome was considered cured when there was no incontinence and with a leakage of less than 2.0 g on the pad test and improved when the frequency of incontinence decreased by more than more than 50% or the pad test showed more than a 50% decrease in leakage.
The Wilcoxon signed rank test was used to evaluate intragroup differences and the effects of the therapy with P < 0.05 were considered significant.
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Urinary incontinence is a devastating medical problem. In Japan, the prevalence of urinary incontinence for men and women has been reported at 10.5% and 53.7%, respectively.10 It has been estimated that only 10–20% of patients with urinary incontinence have overcome their embarrassment and discussed these problems with their doctors.11 The prevalence of incontinence is expected to grow larger as demographics change and the elderly population continues to increase. Conservative therapies include medical management, Kegel exercises, biofeedback, medical management and electrical stimulation. All of these treatments are established for urinary incontinence. Among them, electrical stimulation has been developed for the treatment of urge incontinence as well as stress incontinence.12 The results of electrical stimulation have been reported to be effective for stress incontinence and urge incontinence with success rates of 60–90% and 50–80%, respectively.12,13 However, patients will not always accept electrical stimulation as a treatment option. Some are reluctant to use a probe in the vagina or anus and some patients complain of discomfort or irritation with a probe.
Recently, ExMI has been applied for the treatment of urinary incontinence as a non-invasive method. It is performed with the patient just sitting on a treatment chair without disrobing. ExMI is regarded as a safe and non-invasive alternative treatment for urinary incontinence.
To our knowledge, there have been few reports on magnetic stimulation for the treatment of urge incontinence. Fujishiro et al. performed magnetic stimulation of sacral roots for the treatment of urinary frequency and urge incontinence and reported symptomatic improvement after only a single session.7 Shaker et al. demonstrated that sacral nerve stimulation decreased bladder hyperreflexia by inhibiting afferent C-fiber activity.14 In the present study, 16 (94%) of the 17 patients with stress incontinence and 17 (85%) of the 20 patients with urge incontinence were cured or improved. No adverse effects were noted.
Urodynamic parameters showed significant improvement in the urge incontinence group. Another report has also demonstrated that urodynamic parameters improved after stimulation.6 In the present study, involuntary contractions did not disappear in seven out of eight patients after treatment. However, the volume to involuntary contraction increased in each case.
The treatment parameters for the present study were empiric. Galloway et al. reported that ExMI twice a week for 6 weeks significantly improved stress incontinence and that efficacy was maintained 3 months later.2 Yamanishi et al. reported that magnetic stimulation of the pelvic floor twice weekly for 5 weeks significantly improved stress incontinence, as well as urge incontinence.6 We treated patients twice a week for 8 weeks.
In the present study, both urge and stress incontinence patients significantly improved subjectively and objectively after treatment and 9 out of 17 (52.9%) and 13 out of 16 (81.3%) patients, respectively, maintained improvements for 24 weeks after the last treatment. According to this result, patients with stress incontinence are apt to maintain the effect longer than those with urge incontinence. Optimum pulse duration has not been determined. It has been reported that frequencies of 20–50 Hz are effective for stress urinary incontinence and significantly increased maximum intraurethral pressure during stimulation,15 whereas frequencies of 5–20 Hz have been reported to be optimal for the inhibition of detrusor contraction.16 Yamanishi et al. treated stress incontinence and urge incontinence by 20 Hz and 10 Hz for 15 min twice a week for 5 weeks and reported the success rates to be 86% and 75%, respectively.6 We treated stress and urge incontinence by two different types of frequencies at the same session for 10 min each and also received excellent results.
One of the limitations of the present study is the lack of a control group. It is difficult to design an effective placebo treatment because the patient is aware of the strong contractions of the pelvic floor muscles during the treatment. Fujishiro et al. reported that the improvement rate of stress urinary incontinence in the active group was 74%, significantly higher than the 32% of the control group after the magnetic stimulation of sacral roots.17 Response rates of the present study of 94% and 85% are higher than in previously reported placebo groups. To validate these data, a properly designed placebo controlled study is warranted.