Functional reconstruction of incontinence and voiding disorder due to supranuclear neurogenic bladder by the functional electrical stimulation.

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11835004
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Institution: Tohoku University
• Principal Investigator: HANDA Yasunobu New Industry Creation Hatchery Center, Tohoku University, Professor, 未来科学技術共同研究センター, 教授 (00111790)
• Co-Investigator(Kenkyū-buntansha): FUJII Touru Graduate School of Medicine, Tohoku University, Research Associate, 大学院・医学系研究科, 助手 (70302122) ; NAMIMA Takashige School of Medicine Hospital, Tohoku University, Research Associate, 医学部・附属病院, 助手 (70282069)
• Project Period (FY): 1999 – 2000
• Keywords: functional electrical stimulation / Neurogenic bladder / Voiding disorder / Incontinence

Research Abstract

The aim of this study is to resolve detrusor-sphincter dyssynergia which is generated the electrical stimulation of the anterior sacral nerve root, and to reconstruct the voiding function using the functional electrical stimulation. In present study, following research results were obtained.
1) The development of the stimulator : We developed 2channel/2phase stimulator of which the multiple modulated stimulation of the 2 channels was possible. The features of this stimulator are to produce pulse duration, amplitude and frequency only by giving control voltage which is to each parameter in direct proportion.
2) The response of striated urethral sphincter for the stimulation frequency : The critical fusion frequency of striated urethral sphincter was obtained using the adult male dogs. The average fusion index at 5Hz, 10Hz, 20Hz, 30Hz and 50Hz were 0%, 3.4%, 54.7%, 85.1% and 100%, respectively. Therefore, the critical fusion frequency seemed to be 50Hz and/or above it.
3) The effect of the high-frequency blockade for striated urethral sphincter pressure : The possibility of the block stimulation was examined from the reactivity of striated urethral sphincter for the high frequency stimulation. In the stimulation of 300Hz, the lowering of the pressure by the patent muscle fatigue was observed. On the other hand, in the 3000Hz stimulation, it completely did not rise under stimulation on the intraurethral pressure except for the spike like pressure rising in start and end of the stimulation. It seemed that this finding indicates paralytic effect. Then, we studied the change of the intraurethral pressure for the 50Hz stimulation to the pudendal nerve with or without 3000Hz conditioning stimulus. We anticipated that the rise in the intraurethra pressure to the 50Hz stimulation was perfectly suppressed by the 3000Hz conditioned stimulus. Because, the transmitter in neuromuscular junction of striated urethral sphincter was exhausted by 3000Hz conditioned stimulus. However, 3000Hz conditioned stimulus did not affect intraurethral pressure reaction for the 50Hz stimulation at all.