Different pulse shapes for selective large fibre block in sacral nerve roots using a technique of anodal block: An experimental study

The aim of this study was experimentally to investigate whether it is possible to reduce the charge per phase that is applied during selective large fibre block. Sacral roots in pigs were stimulated. Sacral roots contain large somatic nerve fibres and small parasympathetic nerve fibres. Large nerve fibres that innervate the external urethral and external anal sphincters were selectively blocked using a technique of anodal block. In that way, selective activation of the detrusor muscle and the rectum innervated by parasympathetic fibres could be obtained. The square stimulation pulse was replaced with three different pulse shapes that had the same duration as the square pulse and consisted of a depolarising prepulse and a blocking part of the pulse. Compared with the square pulse, the charge per phase needed for anodal block could be reduced with all three pulse shapes. Maximum reduction of the charge per pulse was 17±6%. A lower charge might make anodal block safer in long-term applications.

[1]  Narendra Bhadra,et al.  Selective suppression of sphincter activation during sacral anterior nerve root stimulation , 2002, Neurourology and urodynamics.

[2]  D. McCreery,et al.  Damage in peripheral nerve from continuous electrical stimulation: Comparison of two stimulus waveforms , 2006, Medical and Biological Engineering and Computing.

[3]  D.B. McCreery,et al.  Charge density and charge per phase as cofactors in neural injury induced by electrical stimulation , 1990, IEEE Transactions on Biomedical Engineering.

[4]  Hessel Wijkstra,et al.  Selective detrusor activation by sacral ventral nerve-root stimulation: results of intraoperative testing in humans during implantation of a Finetech-Brindley system , 1998, World Journal of Urology.

[5]  A. Vučković,et al.  Recto-anal motility responses in the Göttingen minipig to selective stimulation of the ventral sacral nerve roots , 2002 .

[6]  Aleksandra Vuckovic,et al.  Different pulse shapes to obtain small fiber selective activation by anodal blocking-a simulation study , 2004, IEEE Transactions on Biomedical Engineering.

[7]  R. Coggeshall.  Law of separation of function of the spinal roots. , 1980, Physiological reviews.

[8]  Morten Kristian Haugland,et al.  A flexible method for fabrication of nerve cuff electrodes , 1996, Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[9]  M D Craggs,et al.  A technique for anodally blocking large nerve fibres through chronically implanted electrodes. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[10]  E. V. Goodall,et al.  Modeling study of activation and propagation delays during stimulation of peripheral nerve fibers with a tripolar cuff electrode , 1995 .

[11]  Warren M. Grill,et al.  Stimulus waveforms for selective neural stimulation , 1995 .

[12]  J T Mortimer,et al.  Neural and connective tissue response to long-term implantation of multiple contact nerve cuff electrodes. , 2000, Journal of biomedical materials research.

[13]  Hessel Wijkstra,et al.  Acute animal studies on the use of an anodal block to reduce urethral resistance in sacral root stimulation , 1994 .

[14]  J. Holsheimer,et al.  Selective stimulation of sacral nerve roots for bladder control: A study by computer modeling , 1994, IEEE Transactions on Biomedical Engineering.

[15]  J Nilsson,et al.  Differences between the time constant of sensory and motor peripheral nerve fibers: Further studies and considerations , 1998, Muscle & nerve.

[16]  G. E. Loeb,et al.  Cuff electrodes for chronic stimulation and recording of peripheral nerve activity , 1996, Journal of Neuroscience Methods.

[17]  W. Grill,et al.  Inversion of the current-distance relationship by transient depolarization , 1997, IEEE Transactions on Biomedical Engineering.