Expandable interbody implant

• US 10,548,738 B2
• Filed: 04/07/2017
• Issued: 02/04/2020
• Est. Priority Date: 04/07/2016
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Inventors: Milz, Bryan D., Boljonis, Dan
• Primary Examiner(s): Boles, Sameh R
• Application Number:
  US15/481,854
• Publication Number:
  US 20170290671A1
• Time in Patent Office: 1,033 Days
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2002/30482 using a locking cam
• CPC Class Codes: A61F 2002/30523 by means of meshing gear teeth
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30566 Helical springs
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/4693 hydraulic

Abstract

An expandable interbody implant is expandable from a contracted configuration to an expanded configuration by moving opposing first and second vertebral-engaging surfaces apart from one another. The implant includes a locking system for restraining contraction of the implant. The locking system may have a locked configuration, in which the first and second surfaces are prevented from moving back towards the contracted configuration, and the locking system may have an unlocked configuration, in which the first and second surfaces are permitted to move back towards the contracted configuration. The locking system may be controlled by rotation of one or more pinions. The pinions may, in turn, be controlled by linear movement of a rack. The rack may be configured so as to bias the locking system towards the locked configuration. The implant may also include a stop for constraining the maximum expansion of the implant.

Claims

1. A spinal implant for placement between first and second vertebral bodies, comprising:

a first member having a first surface for engaging a first vertebral body;

a second member having a second surface for engaging a second vertebral body;

at least one extendable support element having a contracted configuration to facilitate deployment of the implant between the first and second vertebral bodies, and the extendable support element having at least one extended configuration to extend the first and second members away from one another so that the first and second surfaces are positioned further apart from one another than in the contracted configuration; and

a locking system comprising at least one locking element movable between a locked configuration and an unlocked configuration, wherein the locking element prevents movement of the extendable support element towards the contracted configuration when the locking element is in the locked configuration, and the locking element permits movement of the extendable support element towards the contracted configuration when the locking element is in the unlocked configuration;

wherein the locking element includes a pinion, such that movement of the locking element between the locked and unlocked configuration is actuated by rotation of the pinion;

further comprising a linear rack extending along an axis, the linear rack being linearly translatable along the axis to induce rotation of the pinion.

2. The spinal implant of claim 1, wherein the linear rack moves linearly within a channel, the channel supplying a fluid for extending the extendable support element.

3. The spinal implant of claim 1, wherein the linear rack is biased so as to move the locking element towards the locked configuration.

4. The spinal element of claim 3, wherein the linear rack is biased by a linear spring.

5. The spinal implant of claim 1, wherein the locking system further comprises a second locking element having a second pinion, the second locking element being movable between a locked configuration and an unlocked configuration, wherein the second locking element prevents movement of a second extendable support element towards the contracted configuration when the second locking element is in the locked configuration, and the second locking element permits movement of the second extendable support element towards the contracted configuration when the second locking element is in the unlocked configuration;

wherein movement of the second locking element between the locked and unlocked configuration is actuated by rotation of the second pinion; and

wherein the linear rack is engaged with the pinion and the second pinion for simultaneously rotating the pinion and the second pinion.

6. The spinal element of claim 1, wherein the extendable support element is configured to be extended by a fluid.

7. The spinal element of claim 1, wherein the extendable support element includes a piston slidably received within a cylinder.

8. The spinal element of claim 7, wherein the at least one locking element is received within the cylinder.

9. The spinal element of claim 1, wherein the locking system comprises a plurality of inter-engaging locking elements, including an upper lock support member and a lower lock support member;

wherein the upper lock support member has a multi-stepped support surface, and the lower lock support system has a multi-stepped support surface configured to move into engagement with the multi-stepped support surface of the upper lock support member in the locked configuration; and

wherein the at least one locking element is one of the upper and lower lock support members.

10. The spinal implant of claim 9, wherein the at least one locking element is the lower lock support member, the lower lock support member being rotatable relative to the upper lock support member between the locked configuration and the unlocked configuration in response to rotation of the pinion.

11. The spinal implant of claim 10, wherein the lower lock support member is rotatable relative to the upper lock support member about an axle rigidly connected to one of the first and second members.

12. The spinal implant of claim 10, wherein the extendable support element includes a piston slidably received within a cylinder;

and wherein the upper lock support member is disposed within the piston and the lower lock support member is rotatably received within the cylinder.

13. The spinal implant of claim 1, wherein one of the first and second members defines a slot extending along an extension direction, and the wherein the other of the first and second members includes a projection received within the slot, the projection preventing further extension of the first and second members away from one another when the projection abuts an end of the slot.

14. The spinal implant of claim 13, wherein the at least one extendable support element comprises a first extendable support element and a second extendable support element, and wherein the projection and the slot are positioned between the first and second extendable support elements.

15. The spinal implant of claim 1, wherein at least one of the first surface and the second surface is constructed of a porous metal.

16. The spinal implant of claim 1, wherein the implant has a curved, kidney bean-like shape.

17. The spinal implant of claim 1, wherein the implant has a straight shape along its central longitudinal axis.