Rijkhoff N J, Holsheimer J, Koldewijn E L, Struijk J J, van Kerrebroeck P E, Debruyne F M, Wijkstra H
Department of Urology, University Hospital Nijmegen, The Netherlands.
IEEE Trans Biomed Eng. 1994 May;41(5):413-24. doi: 10.1109/10.293215.
The aim of this study was to investigate theoretically the conditions for the activation of the detrusor muscle without activation of the urethral sphincter and afferent fibers, when stimulating the related sacral roots. Therefore, the sensitivity of excitation and blocking thresholds of nerve fibers within a sacral root to geometric and electrical parameters in tripolar stimulation using a cuff electrode, have been stimulated by a computer model. A 3-D rotationally symmetrical model, representing the geometry and electrical conductivity of a nerve root surrounded by cerebrospinal fluid and a cuff was used, in combination with a model representing the electrical properties of a myelinated nerve fiber. The electric behavior of nerve fibers having different diameters and positions in a sacral root was analyzed and the optimal geometric and electrical parameters to be used for sacral root stimulation were determined. The model predicts that an asymmetrical tripolar cuff can generate unidirectional action potentials in small nerve fibers while blocking the large fibers bidirectionally. This result shows that selective activation of the detrusor may be possible without activation of the urethral sphincter and the afferent fibers.
本研究的目的是从理论上探讨在刺激相关骶神经根时，在不激活尿道括约肌和传入纤维的情况下激活逼尿肌的条件。因此，利用计算机模型模拟了使用袖带电极进行三极刺激时，骶神经根内神经纤维的兴奋阈值和阻断阈值对几何参数和电参数的敏感性。使用了一个三维旋转对称模型，该模型表示被脑脊液和袖带包围的神经根的几何形状和电导率，并结合了一个表示有髓神经纤维电学特性的模型。分析了骶神经根中不同直径和位置的神经纤维的电行为，并确定了用于骶神经根刺激的最佳几何参数和电参数。该模型预测，不对称三极袖带可以在小神经纤维中产生单向动作电位，同时双向阻断大神经纤维。这一结果表明，在不激活尿道括约肌和传入纤维的情况下，选择性激活逼尿肌是可能的。
