Cochlear implant electrode array

Abstract

An electrode array for a cochlear implant is formed with a carrier made, for example from silicone, is preshaped and is formed with a lumen. The array is shaped to assume a first. The array can be straightened, and held in a straight configuration by inserting a stylet into the lumen. The array relaxes to a shape matching the curvature of the cochlea when the lumen is removed. The electrodes of the array are disposed on one side of the array to face the modiolus when the array is inserted into the cochlea.

1 . A cochlear electrode array kit for stimulating an auditory nerve of a patient, said electrode array kit comprising: 
 an elongated carrier having a carrier surface and a lumen extending longitudinally through said carrier;    a plurality of electrodes disposed on said carrier surface; and    a plurality of wires connected to said electrodes and embedded in said carrier to provide signals to said electrodes;    wherein said elongated carrier is arranged and constructed to have a first configuration in which said carrier is insertable into said cochlea and a second configuration in which after insertion, said electrodes are positioned to apply stimulation to said auditory nerve; and    a stylet sized to fit into said lumen and extend substantially through said carrier, said stylet, said wires and said carrier cooperating to change said elongated carrier between said first and second configuration.    
     
     
         2 . The cochlear electrode array kit of  claim 1  wherein said carrier is biased toward said first configuration when said stylet is inserted into said carrier.  
     
     
         3 . The cochlear electrode array kit of  claim 2  wherein said lumen has a cross-sectional dimension which increases as said elongated carrier changes shape from said first to said second configuration to allow said stylet to be withdrawn.  
     
     
         4 . The cochlear electrode array kit of  claim 1  wherein said elongated carrier is made of a silicone material.  
     
     
         5 . The cochlear electrode array kit of  claim 1  wherein said stylet is made of a malleable, biocompatible material.  
     
     
         6 . The cochlear electrode array kit of  claim 5  wherein said malleable, biocompatible material is platinum.  
     
     
         7 . The cochlear electrode array kit of  claim 1  wherein said stylet includes a tip, said tip being more flexible than the rest of said stylet.  
     
     
         8 . The cochlear electrode array kit of  claim 1  wherein said elongated carrier includes a tip, said tip being more straight and flexible than the rest of the said elongated carrier.  
     
     
         9 . The cochlear electrode array kit of  claim 1  wherein said stylet has a variable stiffness.  
     
     
         10 . A cochlear electrode array for a cochlear implant comprising: 
 an elongated carrier having a proximal end and a distal end with an outer surface defining a inner side and an outer side opposite said inner side;    a plurality of electrodes on said outer surface; and    wires connected to said electrodes and extending to said proximal end.    
     
     
         11 . The cochlear electrode array of  claim 10  wherein each of said electrodes is connected to one of said leads.  
     
     
         12 . The cochlear electrode array of  claim 10  wherein at least one of said electrodes is connected to at least two of said leads.  
     
     
         13 . The cochlear electrode array of  claim 10  wherein each of said electrodes comprises a ring collapsed to form a U-shaped member.  
     
     
         14 . The cochlear electrode array of  claim 13  wherein said elongated carrier has a longitudinal axis and wherein said rings are arranged orthogonally to said longitudinal axis.  
     
     
         15 . The cochlear electrode array of  claim 14  wherein said electrodes form a channel, said leads being disposed in said channel.  
     
     
         16 . The cochlear electrode array of  claim 10  wherein said elongated carrier is shaped into a curved configuration to fit inside the cochlea of a person, said cochlea including a modiolus, said electrodes being oriented on said inner side to face said modiolus when said carrier is inserted into the cochlea.  
     
     
         17 . The cochlear electrode array of  claim 10  wherein said outer surface is smooth along said outer side to prevent any damage to the cochlea as said carrier is inserted into the cochlea.  
     
     
         18 . The cochlear electrode array of  claim 10  wherein said electrodes are disposed on said inner side.  
     
     
         19 . A cochlear electrode array comprising: 
 an elongated carrier having a proximal end and a distal end, an inner surface with a plurality of electrodes;    said elongated carrier being formed with a lumen extending through said carrier, said elongated carrier being held in a first configuration by an external member inserted into said lumen;    said elongated carrier having a memory to assume a second configuration, and    said elongated carrier being arranged to assume to said second configuration when said external member is removed from said lumen.    
     
     
         20 . The cochlear electrode array of  claim 19  wherein said elongated carrier is constructed and arranged to assume a curved configuration matching the shape of the cochlea when no member is inserted into said lumen.  
     
     
         21 . The cochlear electrode array of  claim 19  wherein said body is arranged to be retained in said first configuration when the external member is located into the lumen, said carrier being substantially straight in said first configuration.  
     
     
         22 . A method of making a cochlear electrode array for implantation into the cochlea of a patient as part of a cochlear implant system comprising: 
 forming an elongated blank around a curved production stylet;    removing said curved production stylet to create a lumen through said elongated blank;    straightening said elongated blank and inserting a straight production stylet into the said lumen;    attaching electrodes and wires to said elongated blank; and    withdrawing said straight production stylet.    
     
     
         23 . The method of  claim 22  further comprising generating each said electrode by the steps of providing a ring of a conductive material, threading one of said wire through said ring and collapsing said rings to grip said one of said wires.  
     
     
         24 . The method of  claim 23  wherein said step of collapsing includes electrowelding said ring.  
     
     
         25 . The method of  claim 23  wherein each said ring is collapsed into a U-shaped electrode.  
     
     
         26 . The method of  claim 25  wherein the said elongated blank is formed with a channel.  
     
     
         27 . The method of  claim 26  wherein the said wires are placed into the said channel formed in the said elongated blank.  
     
     
         28 . The method of  claim 27  wherein each of said u-shaped electrodes with its said attached wire is placed one-by-one into said channel starting from the tip of the said elongated blank, such that each electrode covers the wires of the electrodes which have been previously placed on the blank.  
     
     
         29 . The method of  claim 22  further comprising positioning said blank with said electrodes into a curved die and applying a moulding material to said blank and said electrodes to form a unitary carrier.  
     
     
         30 . The method of  claim 22  wherein said production stylet is withdrawn from said body first to generate said lumen, said blank is straightened and a second straight stylet inserted to hold said blank in a straight configuration before said electrodes are attached to said blank.  
     
     
         31 . A method of making a cochlear electrode array for implantation into the cochlea of a patient as part of a cochlear implant system comprising: 
 providing a plurality of electrodes, each electrode being attached to a wire;    positioning said electrodes in a spaced relationship in a moulding die with said wires extending toward one end of said moulding die; and    applying a moulding material into said moulding die to form a carrier with said electrodes and wires being embedded in said moulding material.    
     
     
         32 . The method of  claim 31  wherein said electrodes are formed by 
 providing a plurality of rings;  
 welding a wire to each ring; and  
 collapsing each of said rings to form a U-shaped electrode element.  
 
     
     
         33 . The method of  claim 32  further comprising positioning said electrodes in said moulding die to form a channel and positioning said wire in said channel.  
     
     
         34 . The method of  claim 33  further comprising inserting into said moulding die a production stylet before said moulding materials is applied, and removing said production stylet from said carrier to form a lumen therein.  
     
     
         35 . The method of  claim 31  further comprising providing said moulding die in a first shape having a first curvature smaller than the curvature of the shape of the cochlea.  
     
     
         36 . The method of  claim 32  comprising forming the said electrode array such that after straightening said electrode array will relax to a second relaxed curve having a second curvature larger than said first curvature.  
     
     
         37 . The method of  claim 33  wherein the second relaxed curvature matches the curvature of the human cochlea.  
     
     
         38 . A stylet insertion jig, stylet and precurved cochlear electrode array combination for forming a straightened cochlear electrode array, said combination comprising: 
 a precurved cochlear electrode array having a longitudinal lumen adapted to receive a stylet;    an elongated stylet having a long axis;    a jig including: 
 a chassis upon which is mounted a variable engagement means arranged to position said array and said stylet relative to each other, an end section of said lumen intersecting said long axis of said variable engagement means operative to insert said stylet into said lumen;  
 an electrode array straightening means mounted on said chassis and engaging said array and operative to straighten said array.  
   
     
     
         39 . A combination according to  claim 39 , wherein said stylet is formed of a malleable material having an annealed tip at a first end and a loop at a second end, said loop forming a means of engagement.  
     
     
         40 . A combination according to  claim 39 , wherein said straightening means cooperates with said variable engagement means to incrementally straighten said precurved electrode array during insertion of said stylet.  
     
     
         41 . A stylet insertion jig for straightening a precurved cochlear electrode array having a lumen and for inserting a stylet into said lumen, said jig comprising: 
 a chassis upon which is mounted a variable engagement means arranged to position said array and said stylet relative to each other, an end section of said lumen intersecting said long axis of said variable engagement means operative to insert said stylet into said lumen;    an electrode array straightening means mounted on said chassis and engaging said array and operative to straighten said array.    
     
     
         42 . A stylet insertion jig according to claim  41 , wherein said straightening means cooperates with said variable engagement means to incrementally straighten said precurved electrode array during insertion of said stylet.