Method and system for aligning a prosthesis during surgery using active sensors
A method and system for determining the orientation of a surgical tool with respect to a bone of a patient, and a device for positioning a sensor are disclosed. The bone has at least three predetermined reference locations. The method includes: (a) defining a reference plane based on distances between the at least three predetermined reference locations; (b) determining a first sensing location on the bone based on the at least three predetermined reference locations; (c) attaching a first active sensor to the bone at the first sensing location; (d) positioning the surgical tool proximate the bone, the surgical tool including a second active sensor; (e) sensing movement of the bone using the first active sensor; (T) transmitting first information relating to movement of the bone using the first active sensor; (g) sensing movement of the surgical tool using the second active sensor; (h) transmitting second information relating to movement of the surgical tool using the second active sensor; (i) receiving the first and second information from the first and second active sensors; and (j) determining a three-dimensional orientation of the surgical tool with respect to the reference plane based on the first and second information. In some cases, the method may further include displaying the three dimensional orientation information to the user on a display device.
1. A device for positioning a sensor at a predetermined location and orientation on a bone of a patient, the device comprising:
at least three contact members adapted for contacting anatomical landmarks providing reference locations for the bone; and
a guide for positioning at least one sensor mount adapted for attaching the sensor on the bone at the predetermined location and orientation with respect to the at least three contact members, the sensor mount mateable with the sensor,
wherein the guide is removable from the sensor mount when the sensor mount is attached to the bone, such that the device is removable from the patient.
2. The device of claim 1 , wherein the guide comprises a first portion movably connected to a second portion, wherein the first portion is movable between an open position and a closed position, wherein in the closed position, the first portion is in engagement with the second portion to position the sensor mount in the predetermined position, wherein, in the open position, the first portion is disengaged from the second portion to permit removal of the device after the sensor mount is positioned at the predetermined location.
3. The device of claim 1 , wherein the sensor mount is a bone screw.
4. The device of claim 1 further comprising a shaft between at least two of the at least three contact members.
5. The device of claim 4 further comprising an arm operatively connected to the shaft and wherein the guide is coupled to the arm and the arm is movable relative to the least two of the at least three contact members.
6. The device of claim 5 , wherein the arm is rotatable about the shaft.
7. The device of claim 5 , wherein the arm and shaft are fixedly attached and are rotatable with respect to the at least two of the at least three contact members.
8. The device of claim 5 , wherein the arm is positioned at an end of the shaft.
9. The device of claim 4 , wherein the arm is positioned between the at least two of the at least three contact members.
10. The device of claim 4 , wherein the shaft is extendable.
11. The device of claim 10 , wherein the shaft is a telescoping shaft.
12. The device of claim 1 wherein the guide slides off the sensor mount axially.
13. The device of claim 1 wherein the guide mechanically constrains the sensor mount to be inserted in a unique orientation.
14. The device of claim 1 wherein the guide includes an orientation marking for alignment of the sensor in the orientation.
15. The device of claim 1 wherein the bone is a pelvis.
16. The device of claim 1 wherein the sensor is attached to an iliac crest.
17. A method for attaching a sensor to a bone of a patient such that the sensor has a pre-determined position and orientation, comprising:
contacting at least three contact members of the device of claim 1 with corresponding anatomical landmarks of the patient;
while the device is contacted with the anatomical landmarks, attaching a sensor mount to the bone using the guide; and,
in either order:
attaching the sensor on the sensor mount; and
removing the device from the sensor mount while leaving the sensor mount attached to the bone.
18. The method of claim 17 comprising using an orientation marker on the guide to match a with a corresponding marker for aligning the sensor mount in the pre-determined orientation.
19. The method of claim 17 wherein the pre-determined position and orientation is determined using pre-operative scans of the patient.
20. The method of claim 17 further comprising:
pre-operatively configuring the device for the patient to align with the corresponding anatomical references determined using pre-operative scans of the patient.
21. The method of claim 20 wherein the device further comprises a shaft between at least two of the at least three contact members and an arm operatively connected to the shaft and wherein the guide is coupled to the arm and the arm is movable relative to the least two of the at least three contact members, wherein pre-operatively configuring the device comprises adjusting the position of at least one of the shaft, the arm, and the at least three contact members to account for patients of different sizes.
22. The method of claim 17 wherein the device further comprises a shaft between at least two of the at least three contact members and an arm operatively connected to the shaft and wherein the guide is coupled to the arm and the arm is movable relative to the least two of the at least three contact members, the step of contacting comprises contacting a first and second of the at least three contact members to corresponding anatomical references and moving the arm to bring a third of the at least three contact members into contact with a one of the anatomical references.
23. A device for positioning a sensor at a predetermined location and orientation on a bone of a patient, the device comprising:
at least three contact members adapted for contacting anatomical landmarks providing reference locations for the bone; and
a guide for positioning at least one sensor mount adapted for attaching the sensor on the bone at the predetermined location and orientation with respect to the at least three contact members, the sensor mount mateable with the sensor,
wherein the guide comprises a first portion movably connected to a second portion,
wherein the first portion is movable between an open position and a closed position,
wherein in the closed position, the first portion is in engagement with the second portion to position the sensor mount in the predetermined position, and wherein, in the open position, the first portion is disengaged from the second portion to permit removal of the device after the sensor mount is positioned at the predetermined location.