Bone reconstruction and orthopedic implants

Abstract

A surgical navigation system comprising a signal receiver communicatively coupled to a primary processor, the primary processor programmed to utilize a sequential Monte Carlo algorithm to calculate changes in three dimensional position of an inertial measurement unit mounted to a surgical tool, the processor communicatively coupled to a first memory storing tool data unique to each of a plurality of surgical tools, and a second memory storing a model data sufficient to construct a three dimensional model of an anatomical feature, the primary processor communicatively coupled to a display providing visual feedback regarding the three dimensional position of the surgical tool with respect to the anatomical feature.

What is claimed is: 
     
         1 . A method of tracking a surgical instrument in three dimensional space comprising:
 knowing relative dimensions of a plurality of surgical instruments;   knowing a location where a first inertial measurement unit (IMU) is mounted to at least one of the plurality of surgical instruments without requiring calibration or registration;   knowing which of the plurality of surgical instruments the first IMU is mounted to;   calibrating the first IMU;   tracking the first IMU in three dimensional space while mounted to at least one of the plurality of surgical instruments; and,   relaying, to a user, orientation and location information of the at least one surgical instrument to which the first IMU is mounted.   
     
     
         2 . The method of  claim 1 , wherein the relayed orientation and location information is depicted on a visual display. 
     
     
         3 . The method of  claim 2 , wherein the visual display depicts a three dimensional model of the at least one surgical instrument the first IMU is mounted to in addition to a virtual model of a patient anatomy. 
     
     
         4 . The method of  claim 3 , wherein the visual display is updated in real time to depict changes in position of the at least one surgical instrument with respect to the virtual model of the patient anatomy. 
     
     
         5 . The method of  claim 1 , wherein relaying surgical instrument orientation and location information comprises providing information to an indicator associated with the at least one surgical instrument to which the first IMU is mounted. 
     
     
         6 . The method of  claim 6 , wherein the indicator comprises a plurality of lights indicating at least one of whether the at least one surgical instrument is oriented in accordance with a pre-operative plan and what direction the at least one surgical instrument needs to be oriented in accordance with a pre-operative plan. 
     
     
         7 . The method of  claim 1 ,
 further comprising tracking a second IMU mounted to a reference object;   wherein the reference object is a bone comprising at least one of a pelvis, a femur, a humerus, a scapula, and a tibia; and   further comprising registering the first IMU and the second IMU with respect to one another.   
     
     
         8 . The method of  claim 1 , further comprising:
 positioning a registration tool against a patient anatomy in only one orientation and location that precisely matches the patient anatomy, and where the patient-specific registration tool includes the first IMU mounted to it in a known position and orientation;   gathering data from the first IMU while the registration tool is stationary with respect to the patient anatomy;   gathering data from a second IMU rigidly mounted to the patient anatomy;   removing the first IMU from the registration tool; and,   mounting the first IMU to at least one of the plurality of surgical instruments.   
     
     
         9 . A surgical navigation system comprising:
 a first inertial measurement unit (IMU) comprising at least three gyroscopes, at least three accelerometers, and at least three magnetometers;   a software package receiving data from the first IMU, the software package including at least one of preloaded computer aided design models and computer aided design surface models of a plurality of surgical instruments;   a second IMU sending data to the software package; and   a first signal receiver communicatively coupled to the first and second IMUs.   
     
     
         10 . The surgical navigation system of  claim 1 ,
 wherein each of the at least three magnetometers is configured to output a voltage proportional to an applied magnetic field at a point in space within a three dimensional coordinate system; and   wherein each of the at least three magnetometers uses a local or environmental magnetic field as a reference to determine orientation deviation from magnetic north.   
     
     
         11 . The surgical navigation system of  claim 1 ,
 wherein the first signal receiver receives signals from the first and second IMUs in real time; and   wherein the first signal receiver continuously calculates a position of each of the first and second IMUs using received IMU data.   
     
     
         12 . The surgical navigation system of  claim 1 , wherein the first IMU is programmed to temporarily disable a tracking algorithm from using magnetometer data when differing magnetometers provide different data as to a direction of polar north. 
     
     
         13 . The surgical navigation system of  claim 1 ,
 wherein the software package includes a three dimensional virtual model of an anatomical feature; and   wherein the software package is operatively coupled to a display configured to provide visual feedback regarding a three dimensional position of a selected one of the plurality of surgical instruments with respect to the anatomical feature.   
     
     
         14 . The surgical navigation system of  claim 1 ,
 wherein the display is configured to display the three dimensional virtual model of the anatomical feature;   wherein the display is configured to display a three dimensional virtual model of the selected one of the plurality of surgical instruments;   wherein the software package is operative to utilize data from the first IMU to reposition the virtual model of the selected one of the plurality of surgical instruments; and,   wherein the software package is operative to utilize data from the second IMU to reposition the three dimensional virtual model of the anatomical feature.   
     
     
         15 . A surgical navigation system comprising:
 a software package programmed to utilize an algorithm to calculate changes in three dimensional position of a utility inertial measurement unit mounted to a surgical tool; and,   a tangible initialization device precisely matching a surface of an anatomical structure at only a single orientation and location, the initialization device configured to have the utility inertial measurement unit mounted thereto prior to mounting the utility inertial measurement unit to the surgical tool.   
     
     
         16 . The surgical navigation system according to  claim 15 , further comprising:
 a reference inertial measurement unit communicatively coupled to the software package, the reference inertial measurement unit configured to be attached to the anatomical structure.   
     
     
         17 . The surgical navigation system according to  claim 16 , wherein:
 the surgical tool is one of a plurality of surgical tools;   the software package is communicatively coupled to a first memory storing tool data unique to each of the plurality of surgical tools and a second memory storing model data sufficient to construct a three dimensional virtual model of the anatomical structure; and   the software package is communicatively coupled to a display providing visual feedback regarding a three dimensional position of the surgical tool with respect to the anatomical structure.   
     
     
         18 . The surgical navigation system according to  claim 17 , wherein:
 the model data stored in the second memory includes a three dimensional virtual model of the anatomical structure;   the tool data stored in the first memory includes three dimensional virtual models of the plurality of surgical tools;   the display displays the three dimensional virtual model of the anatomical structure;   the display displays the three dimensional virtual model of the surgical tool;   the software package is operative to utilize data from the reference inertial measurement unit to reposition the three dimensional virtual model of the anatomical structure; and,   the software package is operative to utilize data from the utility inertial measurement unit to reposition the three dimensional virtual model of the surgical tool.   
     
     
         19 . The surgical navigation system according to  claim 18 , wherein the software package is operative to utilize the data from the utility inertial measurement unit to reposition the three dimensional virtual model of the surgical tool with respect to the three dimensional virtual model of the anatomical structure in real-time. 
     
     
         20 . The surgical navigation system according to  claim 19 , wherein:
 the tool data stored in the first memory includes positional data indicating the relative distance between an end effector of the surgical tool and a mounting location on the surgical tool for the inertial measurement unit; and,   the surgical tool includes at least one of a reamer, a cup positioner, an impacter, a drill, a saw, and a cutting guide.