Mechanism arrangement for orthopedic simulator

Abstract

An orthopedic simulator is provided with a mechanism with a plurality of sub-mechanisms that generate relative motions between the portions of orthopedic devices, such as spinal disc implants. The sub-mechanisms are configured to be nested so as to place the sub-mechanism with the highest required performance closest to the specimen.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front, perspective view of an orthopedic simulator in accordance with certain embodiments of the invention, with an external housing removed for illustrative purposes, and with forces being schematically depicted.

FIG. 2 a is a top view of the orthopedic simulator of FIG. 1; FIG. 2b is a front view; FIG. 2c is a bottom view and FIG. 2d is a side view.

FIG. 3 is a view similar to FIG. 1, illustrating the removability of a specimen containment module.

FIG. 4 depicts an exemplary embodiment of an assembled specimen containment module.

FIG. 5 is an exploded view of the specimen containment module of FIG. 4.

FIG. 6 is a side, partially cross-sectional view of the specimen containment module of FIG. 4.

FIG. 7 is a top view of a base of the specimen containment module of FIG. 4.

FIG. 8 is a schematic depiction of an embodiment of a circulation loop for circulating a temperature control fluid in a temperature control circuit.

FIG. 9 depicts two test stations, with one test station having a specimen containment module releasably attached thereto.

FIG. 10 schematically depicts an exemplary arrangement for circulating bath fluid.

FIG. 11 depicts an embodiment of a specimen containment module in an installed position.

FIG. 12 is a perspective view of the orthopedic simulator of FIG. 1, with an indication of the flexion and extension motion.

FIG. 13 is a cross-sectional view of a portion of a flexion/extension motion linkage in accordance with embodiments of the invention.

FIG. 14 is a perspective view of the orthopedic simulator of FIG. 1, with an indication of the lateral bending motion around an axis of rotation.

FIG. 15 is a rear perspective view of the orthopedic simulator of FIG. 1.

FIG. 16 is a perspective view of the orthopedic simulator of FIG. 1, with an indication of anterior/posterior and lateral translation motions.

FIG. 17 depicts a portion of an x-y slide assembly in accordance with embodiments of the present invention.

FIG. 18 is a perspective view of the x-y slide assembly in accordance with embodiments of the present invention.

FIG. 19 is an exploded view of the x-y slide assembly of FIG. 18.

FIG. 20 is a perspective view of the orthopedic simulator of FIG. 1, with an indication of loading in a vertical direction.

FIG. 21 is a perspective view of an embodiment of an actuator in isolation.

FIG. 22 is a top view of the actuator of FIG. 21.

FIG. 23 is a side view of the actuator of FIG. 21.

FIG. 24 is a cross-sectional view of the actuator of FIG. 21.

FIG. 25 is a perspective view of the orthopedic simulator of FIG. 1, with an indication of the axial rotation linkage and a moment provided at a test specimen.

FIG. 26 is a rear perspective view of the orthopedic simulator of FIG. 1, illustrating an embodiment of a central manifold in accordance with embodiments of the present invention.

FIGS. 27-29 schematically depict different approaches to linkages.

FIG. 30 schematically depicts a nesting order of forces in accordance with embodiments of the present invention.

FIG. 31 shows the required forces for application to a test specimen intended for a lumbar region according to an exemplary set of curves.

FIG. 32 shows the same information as FIG. 31, but for cervical data.

FIG. 33 shows curves for non-sinusoidal input data in accordance with exemplary embodiments of the invention.

FIG. 34 depicts the orthopedic simulator within a housing.

Claims

1. An orthopedic simulator with a mechanism for applying motions and forces to a test specimen, comprising: a plurality of sub-mechanisms of the mechanism, the sub-mechanisms respectively applying to the test specimen motions and forces with respect to different axes, with at least one of the motions or forces being the motion or force requiring a most demanding performance of the motions or forces applied to the test specimen;wherein the sub-mechanism that applies the motion or force requiring the most demanding performance is sequentially closest to the test specimen in comparison to the other sub-mechanisms.

2. The simulator of claim 1, wherein the sub-mechanisms are nested such that the sub-mechanisms requiring more demanding performance are sequentially closer to the test specimen than the sub-mechanisms requiring less demanding performance.

3. The simulator of claim 2, further comprising drives coupled to the sub-mechanisms to drive the sub-mechanisms, wherein each drive is sequentially further from the test specimen than the sub-mechanism being driven by that drive.

4. The simulator of claim 2, wherein the motions include an My motion, an Mx motion and an Mz motion, and the forces include an Fx force, an Fy force and a Fz force.

5. The simulator of claim 4, wherein the My motion requires the most demanding performance of the motions and the Fy force requires the most demanding performance of the forces, such that the sub-mechanism for applying the My motion and the sub-mechanism for applying the Fy force are sequentially closer to the test specimen than the other sub-mechanisms.

6. The simulator of claim 5, wherein the test specimen is a spinal implant with a superior portion and an inferior portion and the My motion represents flexion/extension, the Mx motion represents lateral bending and the Mz motion represents axial rotation.

7. The simulator of claim 6, wherein the sub-mechanism for applying the My motion is the sequentially closest sub-mechanism to the superior portion of the test specimen and the sub-mechanism for applying the Fy force is the sequentially closest sub-mechanism to the inferior portion of the specimen.

8. The simulator of claim 7, wherein the sub-mechanism for applying the Mx motion is the next sequentially closest sub-mechanism to the superior portion of the test specimen.

9. The simulator of claim 8, wherein the sub-mechanisms for applying the Fx force, for applying the Fz force and for applying the Fz motion are the next sequentially closest sub-mechanisms to the inferior portion of the test specimen in the order of Fx, Fz and Mz, from closer to further.

10. An orthopedic simulator comprising: an My sub-mechanism configured to apply an My motion to a first portion of a test specimen; andan Mx sub-mechanism configured to apply and Mx motion to the first portion of the test specimen; the Mx sub-mechanism being sequentially further from the first portion of the test specimen than the My sub-mechanism.

11. The simulator of claim 10, further comprising a plurality of test stations at which respective test specimens are tested, the My and Mx sub-mechanisms respectively applying the My and Mx motions simultaneously to the test specimens.

12. The simulator of claim 11, wherein the My sub-mechanism includes gimbals respectively coupled to the test specimens to apply the My motion to the test specimen, and wherein each of the gimbals is directly connected to a first common solid cross-piece such that the gimbals are each directly driven via the common cross-piece.

13. The simulator of claim 12, further comprising an Fx and Fy force sub-mechanism, an Fz force sub-mechanism and an Mz sub-mechanism, the Fx and Fy force sub-mechanism being sequentially closer to a second portion of the test specimen than the Fz force sub-mechanism and the Mz sub-mechanism.

14. The simulator of claim 13, wherein the Mz sub-mechanism includes independent linkages to apply Mz motion to each of the test specimens, the independent linkages each being directly connected to a solid second common cross-piece such that each of the independent linkages is directly driven via the second common cross-piece.

15. The simulator of claim 14, wherein the Fz force sub-mechanism comprises a low-friction vertical load actuator.

16. The simulator of claim 13, wherein the test specimens are spinal implants with a superior portion and an inferior portion and the My motion represents flexion/extension, the Mx motion represents lateral bending and the Mz motion represents axial rotation.

17. A spinal implant test machine, comprising: a flexion/extension sub-mechanism for applying flexion/extension rotational motion to a test specimen of a spinal implant;a lateral bending sub-mechanism for applying lateral bending rotation motion to the test specimen; andan axial rotation sub-mechanism for applying axial rotational motion to the test specimen;wherein an Euler sequence of rotational motion applied to the test specimen is flexion/extension>lateral bending>axial rotation.

18. The test machine of claim 17, wherein the flexion/extension sub-mechanism, the lateral bending sub-mechanism and the axial rotation sub-mechanism are independent from one another.

19. The test machine of claim 17, further comprising a controller coupled to the flexion/extension sub-mechanism, the lateral bending sub-mechanism and the axial rotation sub-mechanism, the controller configured to control the movements of the sub-mechanisms and the phases between the sub-mechanisms.