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Case Western Reserve University Patents
Show moreBackground of the invention: The present invention relates to the biomedical arts, particularly implantable nerve cuffs for both stimulating and monitoring nerve activity. The present invention finds application in electrodes embedded in nerve trunks and other small tissue strands and will be described with reference thereto. The invention is also applicable to medicinal infusers and other implanted biomedical devices for introducing, monitoring, or removing matter or energy. Functional electrical stimulation of the nervous system has been shown in recent years to offer great hope in restoring some degree of lost sensory and motor function in stroke victims and individuals with spinal cord lesions. Ways in which functional electrical stimulation can be utilized to restore a particular function include:(1) the use of surface electrodes to activate the nerves in the general region of interest;(2) the use of intramuscular electrodes, also to activate the nerves in a general region;(3) the use of nerve cuff electrodes placed around specific nerves of interest and used to activate them specifically; and,(4) the use of regeneration-type neural interfaces including microelectrode arrays. The third alternative offers advantages over the first two in that it requires the least amount of stimulating current and hence the least amount of charge injected into the tissue itself. Because the use of nerve cuff electrodes requires delicate surgery and may damage the nerves, they are usually contemplated when excitation of specific, isolated muscles is desired, or when unidirectional propagation action potentials is required. The prior art cuff electrodes were of either the split-cylinder type or self-curling coil type. The split-cylinder type included a cylinder of dielectric material defining a bore therethrough of sufficient diameter to receive the nerve trunk to be electrically stimulated. The cylinder had a longitudinal split or opening for receiving a nerve. During installation, the longitudinal split was sutured or otherwise held closed. Although suturing held the cuff in place, an electric current path was defined through the split which permitted current leakage. Also, the suture holding the cuff closed interfered with full expansion of the cuff to accommodate swelling of the nerve. Two or three annular electrodes were positioned on the inner surface of the bore for use in applying the electrical stimuli. The electrical stimuli, for example, may provide functional electrical stimulation, may block natural nerve impulses travelling along the nerve trunk, or the like. The self-curling type prior art cuff electrodes included a self-curling sheet of non-conductive material biased to curl into a tight spiral. A pair of conductive strips are disposed on the self-curling sheet extending peripherally around the diameter of the cuff passage.
http://www.google.com/patents?vid=USPAT5400784
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