| 摘要 |
An implantable electrode in the form a helically wound conductor having an electrically conductive polymeric layer coaxially surrounding and contacting the helically wound conductor, wherein the electrically conductive polymeric layer is electrically conductive in a dry state prior to implantation. Preferably, the electrode has two conductive portions, the additional second conductive portion being preferably located at the distal tip. The implantable electrode preferably incorporates an insulating portion wherein an additional length of the helically wound conductor is continuous with the remaining length of helically wound conductor coaxially covered by the electrically conductive polymeric layer. The insulating portion has a coaxial covering of impermeable polymeric electrically insulating material which is preferably silicone tubing. More preferably the coaxial covering of impermeably polymeric electrically insulating material has an additional exterior coaxial covering of porous PTFE for improved biocompatibility and flexibility. The porous PTFE is preferably porous expanded PTFE having a fibril length of less than 10 microns in order to substantially preclude tissue ingrowth and tissue attachment. The electrically conductive polymeric layer of the electrode is preferably made of porous expanded PTFE containing an electrically conductive filler, the porous expanded PTFE again having a fibril length of less than 10 microns.
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