| Project/Area Number |
07557362
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
Urology
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| Research Institution | Tohoku University |
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Principal Investigator |
ORIKASA Seiichi (1996) Tohoku Univ.Department of Urology, Professor, 医学部, 教授 (60001004)
吉川 和行 (1995) 東北大学, 医学部・付属病院, 講師 (10133977)
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| Co-Investigator(Kenkyū-buntansha) |
NAMIMA Takushige Tohoku Univ.Department of Urology,, 医学部・付属病院, 助手 (70282069)
HANDA Yasunobu Tohoku Univ.Graduate School of Medicine, Professor, 医学部, 教授 (00111790)
折笠 精一 東北大学, 医学部, 教授 (60001004)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1996: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | obstinate ; urinary incontience / functional electrical stimulation / Urethral sphincter / alternate stimulation of the pudendal nerves / Fatigue-resistance / 尿失禁 / 陰部神経 / 運動反応時間 / 周波数変調 / トリガーシステム |
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| Research Abstract |
The purpose of this study is to position the functional electrical stimulation (FES) of the pudendal nerves as a new conservative therapy for obstinate urinary incontinence, and to develop an efficient control system with FES aiming simultaneous maintenance of fatigue-resistance and immediate-response potency of the urethral sphincter. In the course of the study, the following results were obtained. 1) Characteristics of contraction of the urethral sphincter : In the examination of the motor reaction time, etc.on electrical stimulation of the pelvic floor muscle (PFM) and periurethral striated sphincter (PUS) in adult mongrel dogs, the fast muscle was found to be dominating in PUS and the slow muscle in PFM,and possible compatibility of fatigue-resistance of the slow muscle with immediate-response potency of the fast muscle by simultaneous control of these two types of muscles was suggested. 2) Characteristic frequency for urethral closing : Optimal frequency for continuous weak closin
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g of the urethra with good energy efficiency and instantaneous strong constriction was examined, and a minimum of 20 Hz was necessary for stable weak closing and strong constriction appeared to be induced at more than 50 Hz. 3) Long-term control by FES : As a stimulating method to induce weak urethral closing with excellent fatigue resistance, an alternate stimulation method with a frequency for urethral closing at 20 Hz that comprises alternate stimulation of each of bilateral pudendal nerves at 10 Hz with a shift of the phase by pi was devised. Long-term control by this method was compared with that by a simultaneous stimulation method at 20 Hz. The absolute final pressure obtained by alternate stimulation was slightly lower than that by simultaneous stimulation, but the former was maintained at more than 60% of the pressure in the beginning even after 2 hours of stimulation, suggesting a good fatigue resistance. In addition, the pressure difference caused by a transient stimulation (50 Hz) triggered by elevation of abdominal pressure under long-term continuous stimulation was 33(]SY.+-。[)11.5cm H2O in the case of simultaneous stimulation, while that was 163(]SY.+-。[)75.1cm H2O in the case of alternate stimulation ; the elevation was significantly high and the potency of strong urethral constriction was maintained during weak urethral closing for a long time in the case of alternate stimulation. In conclusion, the present FES system comprising the alternate stimulation of bilateral pudendal nerves with addition of changed frequency triggered by abdominal pressure is a method that offers not only simuitaneous control of PUS and PFM having different muscle compositions and good resistance against fatigue by raising the apparent working frequency, but also maintenance of the potency of strong constriction of the urethra dealing with instantaneous elevation of bladder pressure. Therefore, the present system appeared to be a conservative therapy for obstinate urinary i Less
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