Method And Apparatus For Image-Based Navigation

Abstract

A system and method for a procedure that can be performed on any appropriate subject. Procedures can include assembling any appropriate work piece or installing members into a work piece, such as an airframe, autoframe, etc. Regardless of the subject, tracking a substantially small tracking device in a plurality of degrees of freedom is provided. The tracking device can be positioned on or be formed in an instrument to be tracked.

What is claimed is: 
     
         1 . An instrument, comprising:
 an exterior wall that is operable to be moved relative to a subject, wherein the exterior wall has a longitudinal axis and comprises a first depression and a second depression, wherein the second depression is on an opposite side of the exterior wall than the first depression, and wherein a centerline of the first depression extends (i) through a center of the first depression, (ii) perpendicular to the longitudinal axis and (iii) through a center of the second depression; and   a tracking device comprising
 a first conductive wire wound to define a first oval-shaped coil partially disposed in the first depression, wherein the first conductive wire is wound around a first axis of rotation, wherein the first axis of rotation extends through and is at a first angle relative to the longitudinal axis, and wherein the first angle is less than 90°, and 
 a second conductive wire connected in series with the first conductive wire, wherein the second conductive wire is wound to define a second oval-shaped coil partially disposed in the second depression, wherein the second conductive wire is wound around a second axis of rotation, 
   wherein the first oval-shaped coil and the second oval-shaped coil are angularly offset about the exterior wall with respect to and disposed away from the longitudinal axis, and   wherein the first oval-shaped coil and the second oval-shaped coil define respective navigation vectors and provide a combined electromagnetic signal strength that is greater than electromagnetic signal strengths of each of the first oval-shaped coil and the second oval-shaped coil.   
     
     
         2 . The instrument of  claim 1 , wherein:
 the exterior wall comprises a third depression and a fourth depression;   the fourth depression is on an opposite side of the exterior wall than the third depression, wherein a centerline of the third depression extends (i) through a center of the third depression, (ii) perpendicular to the longitudinal axis and (iii) through a center of the fourth depression, and wherein the centerline of the third depression extends perpendicular to the centerline of the first depression; and   the tracking device further comprises
 a third conductive wire wound to define a third oval-shaped coil disposed in the third depression, and 
 a fourth conductive wire wound to define a fourth oval-shaped coil disposed in the fourth depression, 
 wherein the third and fourth oval-shaped coils are connected in series. 
   
     
     
         4 . The instrument of  claim 2 , wherein the third conductive wire and the fourth conductive wire define one or more navigation vectors that are different than the navigation vectors of the first oval-shaped coil and the second oval-shaped coil. 
     
     
         5 . The instrument of  claim 4 , further comprising a fifth conductive wire wrapped around the instrument and the longitudinal axis, wherein the fifth conductive wire defines a navigation vector that is different than each of the navigation vectors of the first oval-shaped coil and the second oval-shaped coil and the one or more navigation vectors of the third oval-shaped coil and the fourth oval-shaped coil. 
     
     
         6 . A navigation system comprising:
 the instrument of  claim 5 ;   a localizer operable to generate an electromagnetic field;   wherein
 the first conductive wire and the second conductive wire sense the electromagnetic field and generate a first signal corresponding to the navigation vectors of the first oval-shaped coil and the second oval-shaped coil, 
 the third conductive wire and the fourth conductive wire sense the electromagnetic field and generate a second signal corresponding to the one or more navigation vectors, and 
 the fifth conductive wire senses the electromagnetic field and generates a third signal corresponding to the navigation vector of the fifth conductive wire; and 
   a navigation processor configured to execute instructions to determine a plurality of degrees of freedom of location information for the instrument based on the first signal, the second signal and the third signal.   
     
     
         7 . The instrument according to  claim 1 , wherein:
 the second axis of rotation is at a second angle relative to the longitudinal axis; and   the second angle is different than the first angle.   
     
     
         8 . The instrument according to  claim 1 , wherein:
 the second axis of rotation is at a second angle relative to the longitudinal axis; and   the second angle is a same angle as the first angle.   
     
     
         9 . The instrument according to  claim 1 , wherein:
 the second axis of rotation is at a second angle relative to the longitudinal axis; and   the second angle is 180° different than the first angle.   
     
     
         10 . The instrument of  claim 1 , wherein the second axis of rotation extends through and is at a second angle relative to the longitudinal axis. 
     
     
         11 . The instrument according to  claim 1 , wherein:
 the second axis of rotation is at a second angle relative to the longitudinal axis; and   the second angle is an inverse of the first angle.   
     
     
         12 . The instrument according to  claim 1 , wherein:
 a distal end of the first oval-shaped coil is at a first radial distance from the longitudinal axis;   a distal end of the second oval-shaped coil is at a second radial distance from the longitudinal axis; and   the second radial distance is equal to the first radial distance.   
     
     
         13 . The instrument according to  claim 12 , wherein:
 a proximal end of the first oval-shaped coil is at a third radial distance from the longitudinal axis;   a proximal end of the second oval-shaped coil is at a fourth radial distance from the longitudinal axis; and   the fourth radial distance is greater than the third radial distance.   
     
     
         14 . The instrument according to  claim 1 , wherein:
 a distal end of the first oval-shaped coil is at a first radial distance from the longitudinal axis;   a distal end of the second oval-shaped coil is at a second radial distance from the longitudinal axis; and   the second radial distance is greater than the first radial distance.   
     
     
         15 . The instrument according to  claim 14 , wherein:
 a proximal end of the first oval-shaped coil is at a third radial distance from the longitudinal axis;   a proximal end of the second oval-shaped coil is at a fourth radial distance from the longitudinal axis; and   the fourth radial distance is equal to the third radial distance.   
     
     
         16 . The instrument according to  claim 1 , wherein:
 the first oval-shaped coil has an interference fit with the first depression; and   the second oval-shaped coil has an interference fit with the second depression.   
     
     
         17 . The instrument according to  claim 1 , wherein:
 the first conductive wire is wound around a first electromagnetic permeable core; and   the second conductive wire is wound around a second electromagnetic permeable core.   
     
     
         18 . A method of manufacturing an instrument, the method comprising:
 forming a flexible exterior wall having a distal end that is operable to be moved relative to a subject and a longitudinal axis, wherein the exterior wall is tubular-shaped and includes a bore for insertion of a cannula, a drill bit or a needle;   forming a first depression and a second depression in the exterior wall, wherein the second depression is on an opposite side of the exterior wall than the first depression, and wherein a centerline of the first depression extends (i) through a center of the first depression, (ii) perpendicular to the longitudinal axis and (iii) through a center of the second depression; and   forming a tracking device by
 winding a first conductive wire around a first axis of rotation a first distance from the distal end to form a first oval-shaped coil,
 winding a second conductive wire around a second axis of rotation at the first distance from the distal end to form a second oval-shaped coil, and 
 connecting the first oval-shaped coil in series with the second oval-shaped coil; and 
 
   attaching the tracking device to the exterior wall including adhering the first oval-shaped coil partially in the first depression and the second oval-shaped coil partially in the second depression, such that (i) the first axis of rotation extends through and is at a first angle relative to the longitudinal axis, and wherein the first angle is less than 90°, (ii) the second axis of rotation extends through and is at a second angle relative to the longitudinal axis, wherein the second angle is different than the first angle, and (iii) the first oval-shaped coil and the second oval-shaped coil define respective navigation vectors.   
     
     
         19 . The method of  claim 18 , further comprising winding a fifth conductive wire around a fifth axis of rotation such that the fifth axis of rotation is parallel to the longitudinal axis. 
     
     
         20 . The method of  claim 18 , further comprising:
 forming a third depression and a fourth depression in the exterior wall, wherein the fourth depression is on an opposite side of the exterior wall than the third depression, and wherein a centerline of the third depression extends (i) through a center of the third depression, (ii) perpendicular to the longitudinal axis and (iii) through a center of the fourth depression;   winding a third conductive wire around a third axis of rotation to form a third oval-shaped coil;   winding a fourth conductive wire around the third axis of rotation to form a fourth oval-shaped coil;   connecting the third oval-shaped coil in series with the fourth oval-shaped coil; and   adhering the third oval-shaped coil partially in the third depression and the fourth oval-shaped coil partially in the fourth depression, such that (i) the third axis of rotation extends through and is at a third angle relative to the longitudinal axis, and wherein the third angle is less than 90°, and (ii) the third oval-shaped coil and the fourth oval-shaped coil define a third navigation vector.   
     
     
         21 . The method of  claim 18 , further comprising:
 forming a third depression and a fourth depression in the exterior wall, wherein the fourth depression is on an opposite side of the exterior wall than the third depression, and wherein a centerline of the third depression extends (i) through a center of the third depression, (ii) perpendicular to the longitudinal axis and (iii) through a center of the fourth depression;   winding a third conductive wire around a third axis of rotation to form a third oval-shaped coil;   winding a fourth conductive wire around a fourth axis of rotation to form a fourth oval-shaped coil;   connecting the third oval-shaped coil in series with the fourth oval-shaped coil; and   adhering the third oval-shaped coil partially in the third depression and the fourth oval-shaped coil partially in the fourth depression, such that (i) the third axis of rotation extends through and is at a third angle relative to the longitudinal axis, and wherein the third angle is less than 90°, (ii) the fourth axis of rotation extends through and is at a fourth angle relative to the longitudinal axis, wherein the fourth angle is different than the third angle, and (iii) the third oval-shaped coil and the fourth oval-shaped coil define respective navigation vectors.   
     
     
         22 . A method of determining location information for a tracking device of an instrument relative to a subject, wherein the instrument comprises an exterior wall, wherein the exterior wall has a longitudinal axis and comprises a first depression and a second depression, wherein the second depression is on an opposite side of the exterior wall than the first depression, wherein a centerline of the first depression extends (i) through a center of the first depression, (ii) perpendicular to the longitudinal axis and (iii) through a center of the second depression, and wherein the tracking device comprises a first oval-shaped coil and a second oval-shaped coil, the method comprising:
 generating an electromagnetic field via a localizer;   detecting the electromagnetic field via the first oval-shaped coil and the second oval-shaped coil, wherein the first oval-shaped coil is partially disposed in the first depression of the exterior wall and is wound around a first axis of rotation, wherein the first axis of rotation extends through and is at a first angle relative to the longitudinal axis, and wherein the first angle is less than 90°, wherein the second oval-shaped coil is partially disposed in the second depression of the exterior wall and is wound around a second axis of rotation, wherein the second axis of rotation extends through and is at a second angle relative to the longitudinal axis, and wherein the second angle is different than the first angle;   generating a first signal via the first oval-shaped coil and the second oval-shaped coil based on the electromagnetic field, wherein the first oval-shaped coil and the second oval-shaped coil define respective navigation vectors, and wherein the first signal corresponds to the navigation vectors; and   executing instructions to determine a plurality of degrees of freedom of location information for the instrument based on the first signal.   
     
     
         23 . The method of  claim 22 , wherein the first oval-shaped coil is connected in series with the second oval-shaped coil. 
     
     
         24 . The method of  claim 22 , wherein the first oval-shaped coil and the second oval-shaped coil are angularly offset about the exterior wall with respect to and disposed away from the longitudinal axis. 
     
     
         25 . The method of  claim 22 , further comprising:
 receiving the first signal from the tracking device as the instrument is moved relative to the subject;   determining a location of the instrument relative to the subject based on the first signal; and   displaying a representation of the determined location of the instrument relative to the subject on a display.   
     
     
         26 . The method of  claim 25 , further comprising:
 detecting the electromagnetic field via a third oval-shaped coil and a fourth oval-shaped coil, wherein the third oval-shaped coil is partially disposed in a third depression of the exterior wall and is wound around a third axis of rotation, wherein the third axis of rotation extends through and is at a third angle relative to the longitudinal axis, wherein the fourth oval-shaped coil is partially disposed in the second depression of the exterior wall and is wound around the third axis of rotation or a fourth axis of rotation, and wherein the fourth axis of rotation extends through and is at a fourth angle relative to the longitudinal axis;   generating a second signal via the third oval-shaped coil and the fourth oval-shaped coil based on the electromagnetic field, wherein the third oval-shaped coil and the fourth oval-shaped coil define one or more navigation vectors, and wherein the second signal corresponds to the one or more navigation vectors;   receiving the second signal from the tracking device as the instrument is moved relative to the subject; and   determining the location of the instrument relative to the subject based on the second signal.   
     
     
         27 . The method of  claim 26 , wherein the third angle is an acute angle. 
     
     
         28 . The method of  claim 26 , wherein the third axis of rotation is perpendicular to the longitudinal axis. 
     
     
         29 . The method of  claim 26 , wherein the fourth angle is different than the third angle. 
     
     
         30 . The method of  claim 26 , further comprising:
 detecting the electromagnetic field via a fifth coil, wherein the fifth coil is wound around a fifth axis of rotation, wherein the fifth axis of rotation is parallel to the longitudinal axis, wherein the fifth coil defines a navigation vector that is different than the navigation vectors of the first oval-shaped coil and the second oval-shaped coil and the one or more navigation vectors of the third oval-shaped coil and the fourth oval-shaped coil;   generating a third signal via the fifth coil; and   determining the plurality of degrees of freedom of location information for the instrument based on the third signal.