Steerable Stylet

Abstract

A stylet for inserting an electrode array into a cochlea includes a first sensor insertable within a lumen of the electrode array and sensitive to force applied by a lumen wall to the first sensor and a first actuator adapted to move the electrode array in response to the force sensed by the first sensor.

What is claimed is: 
     
         1 . A system for inserting an electrode array into a cavity in a body, the system comprising:
 a sensor sensitive to proximity of at least a portion of the electrode array to the body, wherein the sensor is removably insertable into a lumen of the electrode array;   a controller for accepting output from the sensor; and   an actuator removably insertable into a lumen of the electrode array;   wherein the controller operates the actuator responsive to the proximity sensed by the sensor.   
     
     
         2 . The system of  claim 1 , wherein the sensor is incorporated into a stylet that further comprises a polymer body. 
     
     
         3 . The system of  claim 2 , wherein the polymer body comprises a silicone core with an outer parylene coating. 
     
     
         4 . A system for inserting an electrode array into a cavity in a body, the system comprising:
 a stylet for stiffening the a flexible body supporting the electrode array during implantation of the electrode array into the cavity in a body, the stylet comprising a sensor sensitive to proximity of at least a portion of the electrode array to the body, wherein the portion of the stylet bearing the sensor is removably insertable into a lumen of the electrode array;   a controller for accepting output from the sensor; and   an actuator removably insertable into a lumen of the flexible body;   wherein the controller operates the actuator responsive to the proximity sensed by the sensor.   
     
     
         5 . The system of  claim 1 , wherein the sensor is incorporated into a stylet that further comprises a polymer body. 
     
     
         6 . The system of  claim 2 , wherein the polymer body comprises a silicone core with an outer parylene coating. 
     
     
         7 . A system for inserting an electrode array into a cavity in a body, the system comprising:
 a flexible lead body comprising an electrode array, the flexible lead body comprising a stylet lumen for receiving a stylet;   a stylet removably insertable into the stylet lumen for stiffening the flexible lead body during insertion into the cavity in a body, the stylet comprising a plurality of additional lumens;   a sensor sensitive to proximity of at least a portion of the electrode array to the body, wherein the sensor is removably insertable into a first lumen of the additional lumens of the stylet;   a controller for accepting output from the sensor; and   an actuator removably insertable into a second lumen of the additional lumens of the stylet;   wherein the controller operates the actuator responsive to the proximity sensed by the sensor.   
     
     
         8 . The system of  claim 7 , wherein the stylet comprises a polymer body. 
     
     
         9 . The system of  claim 8 , wherein the polymer body comprises a silicone core with an outer parylene coating. 
     
     
         10 . The system of  claim 8 , wherein the polymer body of the stylet has a diameter of less than 0.5 millimeters. 
     
     
         11 . The system of  claim 7 , wherein the additional lumens of the stylet comprise at least four lumens. 
     
     
         12 . The system of  claim 7 , wherein the sensor comprises a piezoresistive sensor. 
     
     
         13 . The system of  claim 12 , in which the piezoresistive sensor comprises a silicon strain gauge configured to detect bending of the stylet around two orthogonal axes of rotation. 
     
     
         14 . The system of  claim 13 , in which the silicon strain gauge comprises two active portions, in which differential measurements between the two active portions measure bending of the stylet in a first axis and summed measurements of the two active portions measure bending of the stylet about a second axis. 
     
     
         15 . The system of  claim 7 , in which the sensor comprises a fiber optic sensor. 
     
     
         16 . The system of  claim 15 , in which the fiber optic sensor comprises at least one of: a Fiber Bragg grating and a Fabry-Perot sensor. 
     
     
         17 . The system of  claim 16 , in which the fiber optic sensor comprises a single optical fiber with a series of Fiber Bragg gratings spaced along a portion of a length of the fiber, each Fiber Bragg grating being tuned to a different wavelength range. 
     
     
         18 . The system of  claim 7 , in which the sensor comprises a pressure sensor. 
     
     
         19 . The system of  claim 18 , in which the pressure sensor is a Fabry-Perot sensor disposed on a distal end of a fiber. 
     
     
         20 . The system of  claim 1 , in which the first sensor is sensitive to force of less than 1 micronewton.