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Keywords:

  • magnetic innervation;
  • urinary incontinence;
  • urodynamics

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

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.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

Magnetic stimulation has been developed for the non-invasive stimulation of the central and peripheral nervous system.1 Recently, this new technology has been applied to pelvic floor therapy and the treatment of stress urinary incontinence.2 It is based on a principle of physics, that a changing magnetic field will induce a flow of electrons within the field. This fundamental property induces controlled depolarization of adjacent nerves and a contraction of muscle. Extracorporeal magnetic innervation (ExMI) has been investigated as an alternative treatment to electrical stimulation in the neurological field.3,4 A magnetic field penetrates body tissues without significant alteration and also passes uninterrupted through clothing. Extracorporeal magnetic innervation can directly stimulate pelvic floor muscles and sacral roots without pain or the insertion of an anal or vaginal plug and can be more efficient and comfortable than conventional electrical stimulation.5 Galloway et al. performed ExMI only for stress urinary incontinence and reported symptomatic improvement.2 To date, there have been a small number of reports published on ExMI treatment for urge incontinence using other original devices.5–7 We have explored whether this new technology is effective for patients with urge incontinence as well as those with stress urinary incontinence.

Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

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 incontinenceUrge incontinence
Number of patients1720
Mean age (years; mean, range)60.1 (29–8068.5 (29–8)
Male : Female0 : 173 : 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)
Type
 I10 
 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.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

Urge incontinence group

Five out of the 20 urge incontinence patients were cured (25.0%), 12 out of the 20 patients improved (60.0%) and 3 out of the 20 patients did not show improvement after treatment (15.0%). The frequency of leak episodes per day was significantly reduced from 5.6 times to 3.6 times at 2 weeks (P = 0.003) (Fig. 1). The effect reached a maximum at 8 weeks. At 24 weeks after the last treatment, two patients were dry and used no pad and four patients used less than one pad per day. Nine out of the 17 patients (52.7%) maintained improvements 24 weeks after the last treatment. Regarding urodynamic testing, the mean first desire to void and maximum cystometric capacities significantly increased from 121.3 ± 51.9 mL to 156.3 ± 60.1 mL, and from 243.8 ± 107.6 mL to 283.9 ± 108.7 mL, respectively, after treatment (Table 2). Involuntary detrusor constructions were demonstrated in eight patients on urodynamic observations before treatment, and in seven patients after. The mean volume of involuntary detrusor contraction significantly increased from 141 ± 50.6 mL before to 188 ± 77.8 mL after treatment (P = 0.018).

image

Figure 1.  Episodes of leakage in patients with urge incontinence. Values are expressed as mean ± standard error. *, P < 0.05.

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Table 2.  Change of urodynamic parameters before and after treatment
 Stress incontinenceP-valueUrge incontinenceP-value
  1. Values are expressed as mean ± standard error. *, P < 0.05.

Bladder capacity at first desire to void (mL)
 Before124.8 ± 36.70.125121.3 ± 51.90.039*
 After125.0 ± 37.8156.3 ± 60.1
Maximum cystometric capacity (mL)
 Before306.8 ± 65.90.25243.8 ± 107.60.004*
 After327.5 ± 32.0283.9 ± 108.7
Valsalva leak point pressure (cmH2O)
 Before 86.2 ± 29.60.25 
 After103.3 ± 56.9

The mean score of I-QOL at baseline was 62.7 and this significantly increased to 77.8 at 4 weeks (P = 0.004) (Fig. 2). The VAS score also significantly improved from 7.82 to 5.45 at 2 weeks after treatment (P = 0.04). Eight patients recurred within 24 weeks after the last treatment (47.1%) and three out of the eight patients wanted maintenance ExMI therapy.

image

Figure 2.  Quality-of-life (I-QOL) scores in patients with urge incontinence. Values are expressed as mean ± standard error. *, P < 0.05.

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Stress incontinence group

Nine out of the 17 patients were cured (52.9%), seven patients improved (41.1%) and one patient did not show any improvement after treatment (6%). In one-hour pad weight testing, the mean pad weight was significantly reduced from 7.9 g to 2.7 g after 4 weeks (P = 0.023,Fig. 3). At 8 weeks, the effect reached a maximum and five patients were dry and used no pads (31.3%) at 24 weeks after the last treatment. The frequency of leak episodes per day was reduced from 3.3 times before to 1.0 times after treatment (P = 0.042). Regarding the urodynamic study, the mean maximum cystometric capacity increased from 306.8 + 65.9 mL to 327.5 + 32.0 mL after treatment. Although Valsalva leak point pressure increased from 86.2 + 29.6 cmH2O to 103.3 + 56.9 cmH2O, this difference was not significant (Table 2). Subjective efficacy was evaluated by I-QOL score and VAS. The mean score of I-QOL at baseline was 68.5 and this increased significantly to 82.8 at 4 weeks (P = 0.001, Fig. 4). The VAS score also significantly improved from 6.33 to 3.21 after treatment (P = 0.042). Three patients recurred and received an operation within 24 weeks after the last treatment.

image

Figure 3.  One-hour pad weight testing in patients with stress urinary incontinence. Values are expressed as mean ± standard error. *, P < 0.05.

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image

Figure 4.  Quality-of-life (I-QOL) score in patients with stress urinary incontinence. Values are expressed as mean ± standard error. *, P < 0.05.

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Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

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.

Conclusion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References

We have demonstrated that ExMI therapy was effective for both stress and urge incontinence. The results for urge incontinence were less effective than for stress urinary incontinence. However, ExMI therapy offers a new option for urge incontinence as well as stress urinary incontinence. Further studies are required to determine how long the treatment should continue, how long effects will last and which kind of maintenance therapy will be necessary.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Methods
  5. Results
  6. Discussion
  7. Conclusion
  8. References