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There are many diseases that could benefit from electrical nerve block. Theproperties of rapid block, rapid reversal and localization makes electrical nerve block animproved option over pharmaceutical options or surgery. Applications exist in manybody systems. Motor block can provide relief from spasticity. Sensory block canprovide pain relief without the possibility of prescription drug abuses. Autonomic blockcan modulate organ systems such as heart rate or blood pressure. These applicationsare all very complex and diverse. In order to provide solutions to these wide range ofproblems and over a varied group of patients, it is advantageous to have as many toolsas possible available to choose from.Kilohertz-frequency alternating current (KHFAC) has been studied extensivelyand applied to many different applications. It fits all the requirements of electricalnerve block. It is also inherently safe, but at the initiation of KHFAC onset activity occurswhich is undesirable in many applications. Direct current (DC) nerve block can be usedwithout causing onset if the parameters are chosen correctly, but with conventionalelectrodes, damage to the nerve can occur in just a few seconds. The damage from DCcan be mitigated with the correct waveform parameters and the correct electrodes.In order to prevent the formation of cytotoxic products at the electrode surface,high capacitance electrodes were developed to extend the amount of charge that couldbe delivered before reactants were formed at the electrode interface. These electrodes,used with a charge balanced direct current (CBDC) waveform were able to extend theamount of time that DC could be applied.The ability to provide even a short burst of DC opened up several novel nerveblock applications. Three different configurations were tested. 1) A CBDC electrode wasused with a KHFAC electrode to block the onset from the KHFAC using DC. 2) The CBDCwaveform was combined with the KHFAC through one electrode to generate thecombined no onset waveform. 3) A DC only application was tested, using a 4 contactCBDC waveform. These applications provide more tools that can be applied to controlof the nervous system. |
