Method and system for tracking objects in computer-assisted surgery

Patent metadata

Field	Value
Publication number	US-10166083-B2
Application number	US-201715681804-A
Country	US
Kind code	B2
Filing date	Aug 21, 2017
Priority date	Mar 2, 2012
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A computer-assisted surgery system comprises instruments adapted to be used to perform tasks related to surgery. A reference device is in a fixed relation to a bone. A rotating magnet creates a magnetic field plane, the rotating magnet being connected to one of the instrument and the reference device. A magnetometer on the other of the instrument and the reference device produces signals as a function of at least its orientation relative to the magnetic field plane. A processing unit tracks said orientation of the instrument relative to the bone using said signals from the magnetometer subjected to the magnetic field plane.

First claim

The invention claimed is:

1. A method for tracking at least one instrument relative to a bone in computer-assisted surgery comprising:
tracking, using one or more processors of a computer-assisted surgery system, a reference orientation of the bone in three axes with a reference device connected to the bone;
creating a magnetic field plane by rotating a magnet connected to one of the instrument and the bone;
using a magnetometer being mounted to the other of the instrument and the bone, producing signals as a function of at least an orientation of the magnetometer relative to the magnetic field plane; and
tracking and outputting, using one or more processors of a computer-assisted surgery system, an orientation of the instrument relative to the three axes of the reference orientation of the bone using said signals from the magnetometer subjected to the magnetic field plane, as the instrument is moved relative to the bone.

2. The method according to claim 1 , wherein the tracking and outputting are performed using the one or more processors in the instrument.

3. The method according to claim 1 , wherein creating the magnetic field plane by rotating the magnet connected to one of the instrument and the bone comprises creating the magnetic field plane by rotating the magnet connected to the bone by the reference device.

4. The method according to claim 1 , wherein tracking the reference orientation of the bone in three axes with the reference device comprises producing data using at least one of inertial sensors and potentiometers on the reference device.

5. The method according to claim 1 , wherein the method is performed on a pelvis, and wherein tracking and outputting the orientation of the instrument comprises tracking and outputting the orientation as the instrument is mated in one of the acetabulum and an acetabular shell.

6. The method according to claim 5 , wherein tracking the reference orientation includes tracking one of said axes of the reference orientation as aligned with a mediolateral axis of the pelvis.

7. The method according to claim 1 , wherein tracking and outputting the orientation of the instrument comprises displaying navigation data of the instrument relative to the bone.

8. The method according to claim 7 , wherein the method is performed on a pelvis, and wherein displaying navigation data of the instrument relative to the bone includes displaying at least one of an anteversion and abduction/adduction of an axis of the instrument relative to the pelvis.

9. The method according to claim 1 , wherein the rotating magnet is connected to the bone by an articulated arm, and further comprising sensing an orientation of the rotating magnet relative to the bone to orient the magnetic field plane.

10. The method according to claim 9 , wherein sensing the orientation of the rotating magnet relative to the bone to orient the magnetic field plane includes obtaining signals from potentiometers on the articulated arm.

11. The method according to claim 1 , further comprising filtering the signals from the magnetometer to remove static effects from earth's magnetic field.

Assignees

• Orthosoft Inc

Inventors

• Paradis Francois
• Zuhars Joel
• Duval Karine
• Chevrier Mathieu

Classifications

• A61F2002/4668

  for measuring angles · CPC title

• A61F2002/4632

  using computer-controlled surgery, e.g. robotic surgery · CPC title

• A61F2/4657 Primary

  Measuring instruments used for implanting artificial joints (for surgical instruments A61B90/06) · CPC title

• A61B34/20

  Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis · CPC title

• A61F2/34

  Acetabular cups · CPC title