COMPUTER-ASSISTED SURGERY TOOLS AND SYSTEM

• US 20080033442A1
• Filed: 08/03/2007
• Published: 02/07/2008
• Est. Priority Date: 08/03/2006
• Status: Active Grant

• Current Assignee: ORTHOsoft ULC. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: ORTHOsoft ULC. (Zimmer Biomet Holdings, Inc.)
• Inventors: AMIOT, Louis-Philippe, Malette, Louis, Szmutny, Eric
• Granted Patent: US 10,405,873 B2
• Time in Patent Office: Days
• US Class Current: 606/80
• CPC Class Codes: A61B 17/1746 for the acetabulum
• CPC Class Codes: A61B 17/175 for preparing the femur for hip prosthesis insertion
• CPC Class Codes: A61B 2034/102 Modelling of surgical devices, implants or prosthesis
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/108 Computer aided selection or customisation of medical implants or cutting guides
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2065 Tracking using image or pattern recognition
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/1077 Measuring of profiles
• CPC Class Codes: A61B 5/4504 Bones A61B5/4547 takes precedence
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 90/11 with guides for needles or instruments, e.g. arcuate slides or ball joints

Abstract

A surface digitizing tool has a film of micro-sensor elements, with each micro-sensor element related in a network affected by a shape of the film. The film is flexible to conform to a shape of a selected surface of an object. A processing unit receives signals from the micro-sensor elements of the network. The processing unit has a model generator producing a model of the selected surface of the object from the signals of the network of resistive elements. A positioning frame aligns a position and orientation of a drilling tool with respect to a bone element.

Claims

1. A model generator system for generating models of objects, comprising:

a surface digitizing tool having a film of micro-sensor elements, with each micro-sensor element related in a network affected by a shape of the film, the film being flexible to conform to a shape of a selected surface of an object;

a processing unit for receiving signals from the micro-sensor elements of the network, the processing unit having a model generator producing a model of the selected surface of the object from the signals of the network of resistive elements.

2. The model generator system according to claim 1, further comprising a tracking apparatus, and wherein:

the surface digitizing tool has a trackable reference connected to the film in a known relation, the trackable reference being tracked by the tracking apparatus; and

the processing unit receives tracking data for the trackable reference and further comprises a position/orientation calculator to calculate from the tracking data a position and orientation of the trackable reference, with the model generator receiving said position and orientation data of the trackable reference to associate the position and orientation data to the known relation between the film and the trackable reference to provide a position and orientation of the selected surface of the object.

3. The model generator system according to claim 2, wherein the tracking apparatus is a passive optical tracking apparatus, and the trackable reference is a selected pattern of retro-reflective spheres.

4. The model generator system according to claim 1, wherein the object is a bone element and the model generator system is used in computer-assisted surgery.

5. The model generator system according to claim 4, wherein the surface digitizing tool has a resilient body, the film of micro-sensors being mounted on the surface of the resilient body, the surface digitizing tool being used to conform to the shape of a bone element cavity with the resilient body deforming to enter the cavity and applying resilient forces against a surface of the cavity, whereby the film of micro-sensors conforms to the shape of the cavity.

6. The model generator system according to claim 5, wherein the bone element cavity is an acetabulum.

7. The model generator system according to claim 4, wherein the surface digitizing tool is used with a bone element having a generally semi-spherical shape, and the processing unit has a center calculator for receiving the model of the selected surface of the bone element and determining a center of the bone element from said model.

8. The model generator system according to claim 7, wherein the bone element is any one of an acetabulum and a femoral head.

9. The model generator system according to claim 1, wherein the micro-sensors are resistive elements.

10. The model generator system according to claim 1, wherein the micro-sensors are capacitive elements.

11. A positioning frame for aligning a position and orientation of a drilling tool with respect to a bone element, comprising:

a connector portion adapted to releasably grasp the bone element;

a support portion operatively connected to the connector portion and positioned with respect to a portion of the bone element to be drilled;

an alignment tube operatively connected to the support portion, the alignment tube being adapted to receive a working end of a drill to align the drill with the bone element; and

joints between the alignment tube and the connector portion to adjust a position and an orientation of the alignment tube with respect to the bone element.

12. The positioning frame according to claim 11, wherein the joints comprise at least one joint providing at least two translational degrees of freedom between the connector portion and the alignment tube to adjust a position of the alignment tube, the two translational degrees-of-freedom being lockable.

13. The positioning frame according to claim 12, further comprising degrees of actuation to control and actuate the at least two translational degrees of freedom.

14. The positioning frame according to claim 11, wherein the joints comprise at least one joint providing at least two rotational degrees of freedom between the connector portion and the alignment tube to adjust an orientation of the alignment tube, the two rotational degrees-of-freedom being lockable.

15. The positioning frame according to claim 11, wherein ends of the connector portions grasping the bone element each have a film of micro-sensor elements, with each micro-sensor element related in a network affected by a shape of the film, the film being flexible to conform to a shape of the bone element so as to provide data pertaining to a geometry of the bone element.

16. The positioning frame according to claim 11, wherein the bone element is a femur, and the connector portion releasably grasp a femoral neck of the femur, and the alignment tube is aligned with a femoral head of the femur.

17. The positioning frame according to claim 11, wherein the joints provide four degrees of freedom between the alignment tube and the connector portion, with at least two degrees of actuation to actuate and control two selected ones of the degrees of freedom.

18. The positioning frame according to claim 11, wherein the support portion has annular body, with the alignment tube being held generally in a center of the annular body, and wherein the connector portion has three legs projecting from the annular body.

19. A method for drilling a bone element in computer-assisted surgery, comprising:

providing a positioning frame having a drill guide with adjustable degrees of freedom for the drill guide in the positioning frame, and a computer-assisted surgery system providing orientation data associated with tracking of the drill guide and of a frame of reference of the bone element;

clamping the positioning frame to the bone element such that the drill guide is in the vicinity of a portion of the bone element to be drilled;

displacing the drill guide along the degrees of freedom as a function of the orientation data from the computer-assisted surgery, until a desired orientation is reached for the drill guide; and

drilling the bone element by passing a drill bit through the drill guide in the desired orientation.

20. The method according to claim 19, wherein displacing the drill guide comprises inserting a drill bit of a drill in the drill guide and moving the drill and the drill guide concurrently.

21. The method according to claim 20, wherein providing orientation data comprises calculating the orientation data as a function of a tracking of the drill.

22. The method according to claim 19, wherein displacing the drill guide comprises locking the degrees of freedom at the selected orientation.

23. The method according to claim 19, wherein displacing the drill guide comprises actuating degrees of actuation to actuate the degrees of freedom.

24. The method according to claim 19, wherein clamping the positioning frame comprises clamping the positioning frame to a femoral neck, such that the drill guide is in the vicinity of a femoral head as the femoral head is drilled.

25. A method for generating a model of an object comprising:

providing a film of micro-sensor elements, with an individual position in the film of each said micro-sensor element known;

obtaining a signal from each said micro-sensor element when the film is shaped to model an object;

determining a shape variation of the film at each said micro-sensor element from the signal; and

generating a model of the object from the shape variation and the individual position of each said micro-sensor element.

26. The method according to claim 25, wherein providing comprises providing a trackable reference connected to the film of micro-sensor elements, with a relation between the film and the trackable reference known, and further comprising tracking the trackable reference, and calculating a position and orientation of the object from the model of the object and the tracking of the trackable reference.

27. The method according to claim 25, wherein obtaining comprises obtaining a signal from each said micro-sensor element when the film is shaped to model a bone element in computer-assisted surgery.

28. The method according to claim 27, wherein obtaining comprises obtaining a signal from each said micro-sensor element when the film is shaped to model at least one of a femoral head and an acetabulum in computer-assisted hip replacement surgery.