Method for manufacturing an active fixation electrode

Abstract

The present invention relates to methods for manufacturing active fixation helices for the stimulation and/or sensing of organs. A first embodiment of a method in accordance with the present invention for making a helix comprises a first step of producing an elongated helix precursor body comprising one or more electrical conductors surrounded by an insulating material. This helix precursor body is then shaped into a helix, material removed in predetermined places in order to expose the areas of the conductors which will be used as electrodes in the final product. The body is coated with an electrically conducting biocompatible coating which is subsequently partly removed in continuous loops from around the electrodes in order to electrically insulate them from each other and to ensure that the electrically active areas of the electrodes are of the correct dimensions.

1 . A method of fabricating an electrically active helix for an electrical medical lead comprising:
 a) forming a helix body having a proximal end and a distal end connected by a plurality of helical revolutions, the helix body comprising at least one electrically conducting core partially surrounded by an insulating sheath, wherein a portion of a surface of each electrically conducting core extending from the distal end towards the proximal end and facing in a predetermined direction is exposed;   b) applying a continuous electrically conducting, biocompatible coating to a surface of the insulating sheath and each exposed surface of each electrically conducting core; and   c) removing a portion of the electrically conducting biocompatible coating on the insulating sheath surrounding each continuous portion of the surface of each electrically conducting core such that the electrically conducting coating on the exposed surface of each electrically conducting core is not in electrical contact with the remaining electrically conducting coating on the insulating sheath.   
     
     
         2 . The method of  claim 1 , wherein step a) comprises:
 i) forming an elongated helix body precursor having a proximal end and a distal end, the helix body precursor comprising at least one electrically conducting core and a surrounding insulating sheath in which there is at least one longitudinally extending slit in the insulating sheath which exposes a portion of each electrically conducting core; and   ii) forming the elongated helix body precursor in a helix body in which a plurality of helical revolutions are formed between the proximal end and the distal end of the helix body precursor, and wherein the exposed surface of each electrically conducting core faces in a predetermined direction.   
     
     
         3 . The method of  claim 2 , wherein step i) comprises the step of forming at least one electrically conducting core surrounded by an insulating sheath which leaves at least one portion of each electrically conducting core exposed. 
     
     
         4 . The method of  claim 2  wherein, in step c) the removal of the portion of electrically conducting biocompatible coating is achieved by polishing or cutting or grinding or a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the biocompatible coating is TiN or TiSiC or platinum black or a metal oxide or other electrically conducting material.