Mid-Scalar Electrode Array

Abstract

In one example, a cochlear lead includes a flexible body, an array of electrodes in the flexible body, and a plurality of wires passing along the array of electrodes. The plurality of wires includes a flexural geometry between each pair of adjacent electrodes and a substantially straight geometry over the electrodes. A method for forming an electrode array with a reduced apical cross section is also provided.

1 - 20 . (canceled) 
     
     
         21 . A cochlear lead comprising:
 an elongate flexible body;   a linear array of electrodes spaced along the flexible body for positioning within a cochlea having a lateral wall and a medial wall;   a plurality of wires having a plurality of strain relief geometries formed therein, wherein each strain relief geometry consists of an arch or a loop that:
 is positioned between a pair of adjacent electrodes in the array, 
 has a first end secured by a first electrode within the pair of adjacent electrodes, 
 has a second end secured by a second electrode within the pair of adjacent electrodes, and 
 lies in a plane that intersects the lateral wall and the medial wall when the electrode array is positioned within the cochlea. 
   
     
     
         22 . The lead of  claim 21 , wherein portions of the wires passing over the electrodes have a substantially straight geometry. 
     
     
         23 . The lead of  claim 21 , wherein the plane is substantially perpendicular to exposed surfaces of the adjacent electrodes. 
     
     
         24 . The lead of  claim 21 , wherein the electrode array has a plane of curvature when positioned within the cochlea, and the strain relief geometry plane of curvature is substantially parallel to the electrode array plane of curvature. 
     
     
         25 . The lead of  claim 21 , wherein the strain relief geometry reduces the bending stiffness of the array compared to an array with straight wires of a similar composition and diameter. 
     
     
         26 . The lead of  claim 21 , wherein strain relief geometry extends into the flexible body at least to the neutral bending axis of the electrode array. 
     
     
         27 . The lead of  claim 21 , wherein the spacing between adjacent electrodes varies along the length of the electrode array, and the radius of curvature of each strain relief geometry is adapted to the distance between the adjacent electrodes. 
     
     
         28 . The lead of  claim 21 , wherein the elastic modulus or diameter of the wires varies along the array. 
     
     
         29 . The lead of  claim 21  wherein the cross sectional area, geometry, elastic modulus, and/or hardness of the flexible body varies along the array. 
     
     
         30 . The lead of  claim 21  wherein cross sectional geometry of the, flexible body changes from circular or square to elliptical or rectangular along the array. 
     
     
         31 . The lead of  claim 21  wherein the electrode size varies along the array. 
     
     
         32 . A method for forming an electrode array for positioning within a cochlea having a lateral wall and a medial wall, comprising:
 forming a plurality of strain relief geometries in a plurality of wires;   positioning each strain relief geometry between a pair of adjacent electrodes;   securing a first end by a first electrode within the pair of adjacent electrodes;   securing a second end by a second electrode within the pair of adjacent electrodes;   placing the wires and the electrodes in a mold;   encapsulating the wires and non-contact portions of the electrodes with encapsulating material;   curing the encapsulating material to form a flexible body; and   removing the electrode array from the mold,   such that each strain relief geometry has a curvature in a plane that intersects the lateral wall and the medial wall when the electrode array is positioned within the cochlea.   
     
     
         33 . The method of  claim 32 , wherein the mold is selected to produce a curved electrode array, the method further comprising selecting a wire that retains the strain relief geometries through multiple straightening cycles of the electrode array. 
     
     
         34 . The method of  claim 32 , wherein the strain relief geometry extends into the silicone body at least to the neutral bending axis of the electrode array. 
     
     
         35 . The method of  claim 32 , further comprising varying the spacing between adjacent electrodes along the length of the electrode array, and adapting the radius of curvature of each strain relief geometry to the distance between the adjacent electrodes. 
     
     
         36 . The method of  claim 32 , further comprising changing the elastic modulus and/or diameter of the wires along the array. 
     
     
         37 . The method of claim.  32 , further comprising changing the cross sectional area, geometry, elastic modulus, and/or hardness of the flexible body along the array. 
     
     
         38 . The method of  claim 32 , further comprising changing the geometry of the flexible body from circular or square to elliptical or rectangular along the array. 
     
     
         39 . The method of  claim 32 , further comprising changing the electrode size along the array. 
     
     
         40 . The method of  claim 32 , wherein the step of securing the first end comprises folding a wing of the first electrode over a straight portion of wire adjacent the first end, and the step of securing the second end comprises welding the second end to the second electrode or folding a wing of the second electrode over a straight portion of wire adjacent the second end.