Acutely stiff implantable electrodes

Abstract

An implantable device for stimulating body tissue that includes an electrode lead body and at least one stimulating electrode contact disposed on the electrode lead body. The electrode lead body may be a percutaneous electrode lead or an electrode paddle that is configured and arranged to be substantially stiff outside the patient's body and during insertion into the patient's body and then becomes non-stiff within the patient's body. The stiffness may be modified using, for example, resorbable materials, temperature sensitive materials, or a lumen within the lead body for introducing a pressurized gas or liquid to modify a stiffness of the lead body. In one embodiment, the lead body may have different acute and/or chronic shapes.

1 . A device for stimulating tissue inside a patient's body, comprising:
 an electrode paddle comprising a resorbable material, wherein the resorbable material of the electrode paddle is configured to render the electrode paddle acutely stiff outside the patient's body and during insertion into the patient's body and then chronically non-stiff within the patient's body; and   a plurality of stimulating electrode contacts disposed on the electrode paddle in at least two adjacent columns, each column comprising a plurality of the stimulation electrode contacts;   wherein the electrode paddle further comprises a paddle body layer having a front surface and a back surface opposing the front surface with the plurality of stimulating electrode contacts disposed on the front surface of the paddle body layer and the resorbable material disposed in a resorbable layer disposed over substantially the entire back surface of the paddle body layer, wherein the front surface of the paddle body and the resorbable layer are configured and arranged for contact with solid tissue of the patient's body when the device is implanted inside the patient's body.   
     
     
         2 . The device of  claim 1 , wherein the resorbable material is configured and arranged to be absorbed into the patient to modify the electrode paddle from acutely stiff to chronically non-stiff over a period of time. The device of  claim 1 , wherein the resorbable layer is disposed solely on the back surface of the paddle body layer. 
     
     
         4 . The device of  claim 1 , wherein the resorbable material comprises a copolymer. 
     
     
         5 . The device of  claim 1 , wherein the paddle body layer comprises an internal lumen transitioning from a proximal end towards a distal end of the paddle body layer along a longitudinal axis of the electrode paddle 
     
     
         6 . The device of  claim 5 , wherein the internal lumen further includes at least one external port in communication with the resorbable layer and configured and arranged to introduce a solvent, passing through the inner lumen and through the at least one external port, to assist in degrading the resorbable material of the resorbable layer. 
     
     
         7 . The device of  claim 1 , wherein the resorbable layer further comprises at least one of a steroid, anti-inflammatory agent, or an antibiotic to be introduced over time to the patient's body as the resorbable material of the resorbable layer is resorbed. 
     
     
         8 . The device of  claim 1 , wherein the resorbable material further comprises a substance that promotes tissue growth. 
     
     
         9 . A device for stimulating tissue inside a patient's body, comprising:
 an electrode paddle comprising a temperature sensitive material, wherein the temperature sensitive material of the electrode paddle is configured to render the electrode paddle acutely stiff outside the patient's body and during insertion into the patient's body and then chronically non-stiff within the patient's body; and   a plurality of stimulating electrode contacts disposed on the electrode paddle in at least two adjacent columns, each column comprising a plurality of the stimulation electrode contacts.   
     
     
         10 . The device of  claim 9 , wherein the electrode paddle further comprises a paddle body layer having a front surface and a back surface opposing the front surface with the plurality of stimulating electrode contacts disposed on the front surface of the paddle body layer and the temperature sensitive material disposed in a layer disposed over substantially the entire back surface of the paddle body layer, wherein the front surface of the paddle body and the layer of temperature sensitive material are configured and arranged for contact with solid tissue of the patient's body when the device is implanted inside the patient's body. 
     
     
         11 . The device of  claim 9 , wherein the temperature sensitive material is acutely stiff at 25° C. and chronically non-stiff at 37° C. 
     
     
         12 . The device of  claim 9 , wherein the temperature sensitive material has a glass transition temperature within a range of 25° C. to 37° C. 
     
     
         13 . A method of implanting a device into body tissue, the method comprising:
 inserting the electrode paddle of the device of  claim 1  into the body tissue; and   making the electrode paddle chronically non-stiff after insertion into the body tissue.   
     
     
         14 . The method of  claim 13 , wherein making the electrode paddle chronically non-stiff further comprises absorbing the resorbable material into the patient over a period of time. 
     
     
         15 . The device of  claim 14 , wherein the resorbable layer further comprises at least one of a steroid, anti-inflammatory agent, or an antibiotic to be introduced over time to the patient's body as the resorbable material of the resorbable layer is resorbed. 
     
     
         16 . The method of  claim 13 , wherein making the electrode paddle chronically non-stiff further comprises introducing a solvent through an internal lumen in the electrode paddle to modify a rate of transition from acutely stiff to chronically non-stiff. 
     
     
         17 . The method of  claim 13 , wherein the resorbable material further comprises a substance that promotes tissue growth. 
     
     
         18 . A method of implanting a device into body tissue, the method comprising:
 inserting the electrode paddle of the device of  claim 8  into the body tissue; and   making the electrode paddle chronically non-stiff after insertion into the body tissue.   
     
     
         19 . The method of  claim 18 , wherein the temperature sensitive material is acutely stiff at 25° C. and chronically non-stiff at 37° C. 
     
     
         20 . The method of  claim 18 , wherein the temperature sensitive material has a glass transition temperature within a range of 25° C. to 37° C.