Non-invasive system and method for tracking bones

Patent metadata

Field	Value
Publication number	US-11446090-B2
Application number	US-201815946857-A
Country	US
Kind code	B2
Filing date	Apr 6, 2018
Priority date	Apr 7, 2017
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

Systems and methods for determining position and orientation of a bone of an anatomical feature are described. These include the use of a wearable holder configured to be mounted about an outer-skin surface of the anatomical feature, such that the anatomical feature and the bone are positioned in fixed relation with respect to the wearable holder when the wearable holder is mounted about the anatomical feature. Reference marker arrays are fixedly mounted to the wearable holder, each being positioned on the wearable holder to identify a landmark of the bone within the wearable holder when the wearable holder is mounted to the anatomical feature. The position and orientation of the reference markers are trackable to determine position and orientation of the wearable holder in a reference coordinate system, thereby enabling position and orientation of the landmarks on the bone to be determined.

First claim

The invention claimed is:

1. A system for determining a position and an orientation of a bone of an anatomical feature, the bone underlying an outer-skin surface of the anatomical feature, the system comprising:
a wearable holder for enclosing at least part of the outer-skin surface of the anatomical feature, wherein the wearable holder is a boot for enclosing the outer-skin surface of a foot and the outer-skin surface of a lower leg, the anatomical feature and the bone being positioned in fixed relation with respect to the holder when the wearable holder is mounted about the anatomical feature;
a plurality of holder imaging devices including a first holder imaging device fixedly mounted to the wearable holder at a first position and at least a second holder imaging device fixedly mounted to the wearable holder at a second position spaced apart from the first position, the first holder imaging device configured to obtain an image of a first landmark of the bone at a time interval and the at least second holder imaging device configured to obtain an image of a second landmark of the bone different from the first landmark at the same time interval;
a bone imaging device separate from the plurality of holder imaging devices and configured to obtain a pre-operative image of the bone in its entirety including at least two landmarks of the bone and other surfaces of the bone, the position and the orientation of the at least two landmarks and the other surfaces of the bone in the pre-operative image being known in a reference coordinate system; and
a processing unit configured to compare the images of the first and second landmarks at said time interval to the at least two landmarks in the pre-operative image, and to match the images of the first and second landmarks to the at least two landmarks in the pre-operative image in order to determine the position and the orientation of any portion of a remainder of the bone in the reference coordinate system at said time interval.

2. The system as defined in claim 1 , wherein the bone imaging device is configured to construct the pre-operative image of the bone from at least two images taken in non-coplanar planes.

3. The system as defined in claim 1 , wherein the plurality of holder imaging devices are configured to obtain a contour of the bone underlying the wearable holder.

4. The system as defined in claim 1 , further comprising a plurality of reference markers fixedly mounted to the holder, the position and the orientation of the reference markers being trackable in the reference coordinate system to determine the position and the orientation of the holder in the reference coordinate system.

5. The system as defined in claim 1 , wherein the wearable holder includes a first probe mountable about the outer-skin surface of an upper portion of the leg having an underlying femur, and a second probe mountable about the outer-skin surface of a lower portion of the leg having the underlying tibia.

6. The system as defined in claim 1 , wherein the plurality of holder imaging devices include an ultrasound imaging device.

7. The system as defined in claim 1 , wherein the bone imaging device is configured to obtain the pre-operative image of the bone from a library of pre-operative bone images.

8. The system as defined in claim 1 , wherein the plurality of holder imaging devices are located on the boot to overlie approximate locations of medial and lateral malleoli of the bone of the anatomical feature.

9. The system as defined in claim 1 , wherein the first position of the first holder imaging device is on an opposite side of the wearable holder as the second position of the at least second holder imaging device.

10. The system as defined in claim 1 , wherein the first holder imaging device and the at least second holder imaging device remain in fixed position relative to each other.

11. The system as defined in claim 1 , wherein the wearable holder includes a first strap and at least a second strap extending around the wearable holder for securing the wearable holder to the anatomical feature in fixed relation to the anatomical feature.

12. The system as defined in claim 11 , wherein the first position and the second position of the plurality of holder imaging devices are on an outer surface of the wearable holder between the first strap and the at least second strap.

13. A method for determining a position and an orientation of a bone of an anatomical feature, the method comprising:
obtaining, with a bone imaging device, a pre-operative image of the bone in its entirety including at least two landmarks of the bone and other surfaces of the bone, the position and the orientation of the at least two landmarks and the other surfaces of the bone in the pre-operative image being known in a reference coordinate system;
removably attaching in a non-invasive manner a holder to the anatomical feature to fix a position of the anatomical feature and the bone with respect to the holder, wherein the wearable holder is a boot for enclosing the outer-skin surface of a foot and the outer-skin surface of a lower leg;
obtaining an image of a first landmark of the bone at a given time interval with a first holder imaging device of the holder and obtaining an image of a second landmark of the bone at the given time interval with a second holder imaging device of the holder, the first and second holder imaging devices being separate from the bone imaging device, the first and second landmarks being fixed in position with respect to the holder;
matching the images of the first and second landmarks at the given time interval with the at least two landmarks of the bone in the pre-operative image of the body to register the first and second landmarks of the image and the at least two landmarks of the pre-operative image to generate registered landmarks; and
using the registered landmarks, determining the position and the orientation of any portion of the bone in the reference coordinate system at the given time interval.

14. The method as defined in claim 13 , wherein obtaining the pre-operative image includes constructing the pre-operative image from at least two images taken in non-coplanar planes.

15. The method as defined in claim 13 , wherein obtaining an image of the first landmark and of the second landmark includes obtaining a contour of the bone underlying the holder.

16. The method as defined in claim 13 , further comprising registering position and orientation readings of reference markers fixedly mounted to the holder in the reference coordinate system, and determining the position and the orientation of the holder using the position and orientation readings of the reference markers to thereby determine the position and orientation of the first and second landmarks of the bone in the reference coordinate system.

17. The method as defined in claim 13 , comprising tracking the position and the orientation of any portion of the bone in the reference coordinate system by comparing shifts in position and orientation between the images of the first and second landmarks and the at least two landmarks of the pre-operative image.

18. The method as defined in claim 13 , comprising tracking the position and the orientation of any portion of the bone in the reference coordinate system by only tracking the registered landmarks.

Assignees

• Orthosoft Inc
• Orthosoft Ulc

Inventors

• Li Di
• Amiot Louis-Philippe
• Couture Pierre

Classifications

• A61B5/1075

  for measuring dimensions by non-invasive methods, e.g. for determining thickness of tissue layer (A61B8/0858 takes precedence) · CPC title

• A61B2034/2068

  using pointers, e.g. pointers having reference marks for determining coordinates of body points · CPC title

• A61B34/20

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

• A61B2034/2055

  Optical tracking systems · CPC title

• A61B90/361

  Image-producing devices, e.g. surgical cameras · CPC title