Bone reposition device, method and system

• US 20070043354A1
• Filed: 08/03/2005
• Published: 02/22/2007
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: Hong Kong Polytechnic University
• Original Assignee: Hong Kong Polytechnic University
• Inventors: Koo, Terry, Mak, Arthur, Chao, Edmund
• Granted Patent: US 7,881,771 B2
• Time in Patent Office: Days
• US Class Current: 606/58
• CPC Class Codes: A61B 17/6416 with non-continuous, e.g. hinged, pin-clamp connecting element A61B17/6425, A61B17/6441 take precedence
• CPC Class Codes: A61B 17/66 Alignment, compression or distraction mechanisms
• CPC Class Codes: A61B 90/39 Markers, e.g. radio-opaque or breast lesions markers

Abstract

A bone reposition device includes first and second bone supports for supporting first and second portions of a fracture or osteotomize bone about a fracture or osteotomize site, a plurality of sequentially connected connection members and a plurality of joints each with at least a pair of adjacent parts for connecting the connection members therebetween and to the first and second bone supports. The plurality of joints includes at least six joints, each of which possesses one degree of freedom and allows controllable relative rotation or translation of said pair of adjacent parts about one of three axes respectively.

Claims

1. A bone reposition device, comprising:

first and second bone supports for supporting first and second portions of a fractured or osteotomized bone about a fracture or osteotomize site;

a plurality of sequentially connected connection members; and

a plurality of joints each with at least a pair of adjacent parts for connecting the connection members therebetween and to the first and second bone supports,

wherein the plurality of joints includes at least six joints, each of which possesses one degree of freedom and allows controllable relative rotation or translation of said pair of adjacent parts about its respective axis, and wherein the six axes extend at a degree relative to each other.

2. The bone reposition device of claim 1, wherein the six axes are about one of a set of three axes at its neutral configuration, and wherein the three axes are at least substantially perpendicular to each other.

3. The bone reposition device of claim 1, wherein the first and second bone supports each includes at least two elongate members for attaching to the respective bone segment.

4. The bone reposition device of claim 3, further comprising first and second offset locaters attachable to the first bone support and third and fourth offset locators attachable to the second bone support for reattaching the first and second bone supports to the elongate members after adjustment of the joints.

5. The bone reposition device of claim 4, wherein each offset locater is attachable to the respective elongate member.

6. The bone reposition device of claim 3, further comprising first and second marker holders attachable to the first and second bone supports, wherein each marker holder includes markers for assisting to define relative orientations and positions of the first and second bone segments, and wherein each maker has a fixed position relative to its respective bone segment when the marker holders are attached to the bone supports respectively.

7. The bone reposition device of claim 6, wherein each marker holder includes at least three non-collinear metal fiducial markers embedded on its external surface for defining a local coordinate system of its respective bone potion.

8. The bone reposition device of claim 1, further comprising at least six precision scales or position transducers attachable to the six joints respectively for controlling relative rotations of respective pair of adjacent parts.

9. The bone reposition device of claim 1, further comprising at least six motors, each being connected to one of the six joints or one of said pair of adjacent parts of one of said six joints respectively for driving relative rotation of said pair of adjacent parts.

10. The bone reposition device of claim 9, wherein said motors are designed to be stepping motors.

11. The bone reposition device of claim 1, wherein at least three of the said six joints each includes a projection extending outward from one of said pair of adjacent parts and fitting into a receptacle groove on the other adjacent part, and wherein size of said receptacle groove is adjustable such that stiffness of said three joints can be adjusted.

12. The bone reposition device of claim 1, comprising first and second portions having the first and second bone support respectively, the first and second portions rotatable relative to each other along a longitudinal axis, each of the first and second portions including two revolute joints and one telescopic joint, each of the joint possessing one degree of freedom and allowing relative rotation and translation respectively of said pair of adjacent parts about its respective axis respectively, and each of three axes being at a degree to each other and to the longitudinal axis.

13. The fracture reduction device, comprising four transducers attachable to said four revolute joints for measuring the adjustments thereof, a measurement scale attachable to a joint about which the first and second portions rotates for measuring the adjustment, and two measurement scales attachable to said two telescopic joints for measuring the adjustments.

14. A process for reducing fracture of a fractured bone, the fractured bone having first and second portions about a fracture site, comprising

attaching a bone reposition device to the fractured bone, the bone reposition device including

first and second bone supports for supporting said first and second bone fragments;

a plurality of sequentially connected connection members; and

a plurality of joints each with at least a pair of adjacent parts for connecting the connection members therebetween and to the first and second bone supports,

wherein the plurality of joints includes at least six joints, each of which possesses one degree of freedom and allows controllable relative rotation or translation of said pair of adjacent parts about its respective axis, and wherein the six axes extends at a degree relative to each other,

scanning the fractured bone for obtaining a three-dimensional image of the fracture fragments;

determining an adjustment factor for each of said six joints based upon the three-dimensional image; and

relatively rotating or translating each said pair of adjacent parts of said six joints about its respective axis in view of its respective adjustment factor for executing said fraction reduction.

15. The process of claim 14, further comprising

attaching first and second marker holders to the first and second bone supports respectively;

and

scanning the fractured bone and the marker holders for obtaining a three-dimensional image of the fracture fragments and the marker holders.

16. The process of claim 15, further comprising

creating a virtual model of the fracture fragments using the three-dimensional image of the fracture fragments;

and

reducing the fracture deformity within the virtual model.

17. The process of claim 16, further comprising

determining a desired transformation matrix between the first and second bone portions at the state “

after reduction”

using the marker coordinates; and

determining an adjustment factor for each of said six joints based upon the said transformation matrix.

18. The process of claim 14, wherein the first and second bone supports each includes at least two elongate members detachably mounted to its respective bone support for attaching to the respective bone fragment.

19. The process of claim 18, comprising

attaching first and second marker holders to the respective elongate members, wherein each marker holder includes at least three non-collinear markers for assisting to define relative orientations and positions of the first and second bone segments, and wherein each maker has a fixed position relative to its respective bone fragment when the marker holders are attached to the bone supports respectively.

20. The process of claim 19, comprising

establishing local coordinate systems for the first and second bone fragments with assistance of the markers;

and

determining the adjustment factors in view of the local coordinate systems.

21. The process of claim 17, comprising

after scanning, detaching the marker holders from the bone reposition device;

attaching first, second offset locaters to the elongate members of the first bone support and attaching third and fourth offset locators to the elongate members of the second bone support;

detaching the bone reposition device from the fractured bone, with the first and second elongate members remaining in the fractured bone and the offset locaters on the elongate members; and

during execution of said fraction reduction, aligning the adjusted bone reposition device to the offset locaters for repositioning of the fracture fragments.

22. The process of claim 14, wherein the bone reposition device includes at least six precision scales or position transducers attachable to the six joints respectively for controlling relative rotations of respective pair of adjacent parts.

23. The process of claim 14, wherein the bone reposition device includes at least six motors, each being connected to one of the six joints or one of said pair of adjacent parts of one of said six joints respectively for driving relative rotation of said pair of adjacent parts.

24. The process of claim 14, wherein the scanning step is executed by using a three-dimensional medical imaging process.

25. The process of claim 24, wherein the scanning step is executed by using computed tomography technology.

26. The process of claim 14, wherein the bone reposition device includes first and second portions having the first and second bone support respectively, the first and second portions rotatable relative to each other along a longitudinal axis, each of the first and second portions including two revolute joints and one telescopic joint, each of the joint possessing one degree of freedom and allowing relative rotation and translation respectively of said pair of adjacent parts about its respective axis respectively, and each of three axes being at a degree to each other and to the longitudinal axis.

27. The process of claim 14, comprising ascertaining the principle axes of the first and second bone portions are at least substantially align;

ascertaining the limb length is at least substantially equivalent to that of the contralateral side; and

determining the adjustment factors in view of the principle axes and limb length.

28. The process of claim 14, wherein the six axes are about one of the three axes at its neutral configuration, and wherein the three axes are at least substantially perpendicular to each other.

29. A bone reposition system for reducing fracture of a fractured bone, the fractured bone having first and second portions about a fracture site, comprising:

a bone reposition device attachable to the fractured bone, the bone reposition device including

first and second bone supports for supporting said first and second bone fragments;

a plurality of sequentially connected connection members; and

a plurality of joints each with at least a pair of adjacent parts for connecting the connection members therebetween and to the first and second bone supports,

wherein the plurality of joints includes at least six joints, each of which possesses one degree of freedom and allows controllable relative rotation or translation of said pair of adjacent parts about its respective axis, and wherein the six axes extend at a degree relative to each other,

a three-dimensional medical imaging device for scanning the fractured bone and the marker holders for obtaining a three-dimensional image of the fracture bone and the marker holders, and

a computing device for determining an adjustment factor for each of said six joints based upon the three-dimensional image,

wherein each said pair of adjacent parts of said six joints is relatively rotated about its respective axis in view of its respective adjustment factor for executing said fraction reduction.