Steroid eluting electrode for peripheral nerve stimulation

Abstract

An improved electrode for establishing electrical contact with a nerve of a patient. This electrical contact may be used to sense neural activity on the nerve or to artificially stimulate it to perform various medical treatments. One embodiment of the electrode has an outer cuff of an insulating material which is sutured around the nerve to be contacted. A drug impregnated layer of material is positioned inside of the outer cuff. This material is a polymeric matrix which permits the drug to leach out at a predetermined rate. The drug is preferably a glucocortico steroid such as dexamethasone sodium phosphate. The actual electrical contact is produced by metallic foil which is positioned on the surface of the drug impregnated layer of material which is located inside of the cuff. A second embodiment employs a half cuff which is held in contact with the nerve tissue by being sutured to muscle tissue. The insulative substrate of the half cuff is a drug impregnated polymeric matrix. The electrode is a metallic disc, preferably round or oval in shape, which is recessed into the insulative substrate. An insulated lead electrically couples the metallic foil or metallic disc to an electronic circuit located remote from the nerve. The leaching out of the drug serves to control inflammation, irritation and swelling, and stabilizes the impedance and threshold of the nerve/electrode interface.