Subcutaneous electrode for stimulating skeletal musculature

Claim 2

An implantable device for electrically stimulating skeletal musculature or sensing electrical potential, comprising: an electrode subcutaneously implantable beneath the skin and physically separated from the skeletal musculature and nerves controlling the skeletal musculature, said electrode comprising a single sheet of electrically conductive material having a first surface adapted to face the skeletal musculature and an opposite surface adapted to face away from the skeletal musculature, said electrode defined by an outer perimetric edge; a flexible casing comprising (i) a first layer of flexible biocompatible material adjacent to and substantially covering said opposite surface of said electrically conductive sheet, and (ii) a second layer of flexible biocompatible material covering a portion of said first surface of said electrode and provided with at least one central opening therein for exposing said first surface of said sheet of electrically conductive material, said electrically conductive sheet having a surface area sufficiently large to maintain a charge density of no more than 0.25 μC/mm 2 so as to prevent corrosion of the electrode and damage to surrounding tissue; and at least one electrical lead attached at one end to said electrically conductive sheet and attachable at an opposite end to an electrical current source.

Claim 3

The device of claim 1, wherein said at least one central opening is defined by a perimetric border, said perimetric border extending from said at least one central opening to said outer perimetric edge of said electrode and having no apertures therein.

Claim 4

The device of claim 2 wherein said electrode is implantable adjacent a fatty layer beneath the skin.

Claim 5

The device of claim 2, wherein said electrically conductive sheet is generally planar and is comprised of a noble metal.

Claim 6

The device of claim 4, wherein said generally planar electrically conductive sheet is comprised of platinum.

Claim 7

The device of claim 2, wherein said flexible casing further comprises a fabric mesh intermediate said second layer of flexible biocompatible material and said first surface of said electrically conductive sheet.

Claim 8

The device of claim 6, wherein said fabric mesh is constructed from polyethyleneterephthalate and said first and second layers of flexible biocompatible material are constructed from a silicone elastomer.

Claim 9

The device of claim 6, wherein at least said first surface of said electrically conductive sheet is coated with an oxide coating.

Claim 10

The device of claim 2, wherein said at least one electrical lead is attached at one end to said electrically conductive sheet by spot welding.

Claim 11

The device of claim 9, wherein said at least one electrical lead comprises a pair of electrical leads, each of said leads being wrapped generally in the form of a helix around a core.

Claim 12

The device of claim 10, wherein a portion of each of said helically wrapped leads is coiled, thereby forming a compound helical section.

Claim 13

The device of claim 11, wherein said electrical leads are formed of stranded stainless steel wire.

Claim 14

The device of claim 12, wherein said electrical leads comprise wire constructed from a cobalt alloy.

Claim 15

The device of claim 12, wherein said stainless steel wire is coated with polytetrafluoroethylene and wound around a flexible and biocompatible polypropylene core.

Claim 16

The device of claim 12, wherein at least a portion of each of the helically wound electrical leads are covered by flexible tubing.

Claim 19

An implantable device for electrically stimulating skeletal musculature or sensing electrical potential, comprising: an electrode subcutaneously implantable beneath the skin and physically separated from the skeletal musculature and nerves controlling the skeletal musculature, said electrode comprising a single sheet of electrically conductive material having a first surface adapted to face the skeletal musculature and an opposite surface adapted to face away from the skeletal musculature, said electrically conductive sheet having a surface area sufficiently large to maintain a charge density of less than 0.25 μC/mm 2 so as to prevent corrosion of the electrode and damage to surrounding tissue; a flexible casing covering at least a substantial portion of said opposite surface of said electrically conductive sheet, said flexible casing comprising (i) a first layer of flexible biocompatible material of a thickness not to exceed 0.5 millimeter adjacent said opposite surface of said electrically conductive sheet, (ii) a second layer of flexible biocompatible material of a thickness not to exceed 0.5 millimeter surrounding a perimeter of said first surface of said electrically conductive sheet and (iii) a fabric mesh intermediate said second layer of flexible biocompatible material and said first surface of said electrically conductive sheet; and at least one electrical lead attached at one end to said electrically conductive sheet and attachable at an opposite end to an electrical current source.

Claim 20

An implantable device for electrically stimulating skeletal musculature or sensing electrical potential, comprising: an electrode subcutaneously implantable beneath the skin and physically separated from the skeletal musculature and nerves controlling the skeletal musculature, said electrode comprising a single sheet of electrically conductive material having a first surface adapted to face the skeletal musculature and an opposite surface adapted to face away from the skeletal musculature, said electrically conductive sheet having a surface area sufficiently large to maintain a charge density of less than 0.25 μC/mm 2 so as to prevent corrosion of the electrode and damage to surrounding tissue; a flexible casing covering at least a substantial portion of said opposite surface of said electrically conductive sheet, said flexible casing comprising (i) a first layer of flexible biocompatible material of a thickness not to exceed 0.5 millimeter adjacent said opposite surface of said electrically conductive sheet, (ii) a second layer of flexible biocompatible material of a thickness not to exceed 0.5 millimeter surrounding a perimeter of said first surface of said electrically conductive sheet and (iii) a fabric mesh intermediate said second layer of flexible biocompatible material and said first surface of said electrically conductive sheet; and at least one electrical lead attached at one end to said electrically conductive sheet and attachable at an opposite end to an electrical current source.