Rod reduction device

• US 20170325855A1
• Filed: 11/09/2015
• Published: 11/16/2017
• Est. Priority Date: 11/10/2014
• Status: Active Grant

• Current Assignee: Spinal Developments Pty Ltd., A.T.F. the Spinesr Unit Trust
• Original Assignee: Spinal Developments Pty Ltd., A.T.F. the Spinesr Unit Trust
• Inventors: ROGER, Gregory, SARAVANJA, Davor
• Granted Patent: US 10,420,592 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 17/7085 for insertion of a longitudinal element down one or more hollow screw or hook extensions, i.e. at least a part of the element within an extension has a component of movement parallel to the extension's axis
• CPC Class Codes: A61B 17/7086 Rod reducers, i.e. devices providing a mechanical advantage to allow a user to force a rod into or onto an anchor head other than by means of a rod-to-bone anchor locking element; rod removers

Abstract

An orthopedic bone rod reduction device and method is disclosed. The device includes an actuator having a drive surface and a bone rod engagement element for engaging with a bone rod. The assembly further includes a spring positioned between the drive surface of the actuator and the rod engagement element. The rod reduction assembly controls movement of a bone rod relative to a bone anchor positioned in a bone.

Claims

1. An orthopedic rod reduction device comprising:

an actuator having a drive surface;

a rod engagement element for engaging a rod and moving the rod upon movement of the actuator, and

a spring positioned between the drive surface of the actuator and the rod engagement element.

2. The orthopedic rod reduction device of claim 1, wherein the actuator comprises a drive head having upper and lower opposed surfaces and further, a drive shaft which extends from a proximal end connected to the lower surface of the head member to a distal end which is connected to the rod engagement element.

3. The orthopedic rod reduction device of claim 2, wherein the drive shaft includes an internal lumen.

4. The orthopedic rod reduction device of claim 3, wherein the spring is at least partially housed within the internal lumen of the elongate shaft.

5. The orthopedic rod reduction device of any one of claims 2 to 4, wherein a length of the drive shaft includes a threaded outer surface.

6. The orthopedic rod reduction device of any one of claims 2 to 5, further comprising a support having a proximal head and a bone anchor engaging portion which extends distally from the proximal head.

7. The orthopedic rod reduction device of claim 6, wherein the proximal head includes a passage defined by at least a partially threaded portion of an internal wall of the proximal head, said passage configured to receive at least a length of the drive shaft.

8. The orthopedic rod reduction device of claim 7, wherein the thread of the partially threaded portion of the internal wall of the proximal head is complementary to the thread of the drive shaft.

9. The orthopedic rod reduction device of claim 8, wherein the drive head is rotatably moveable relative to the proximal head of the support and rotation of the drive head relative to the proximal head of the support effects a linear translational movement of the drive head and drive shaft relative to the proximal head.

10. The orthopedic rod reduction device of any one of claims 6 to 9, wherein the bone anchor engaging portion of the support includes a plurality of elongate legs each extending distally from the proximal head from a first end to a second end, the second end of the elongate legs including one or more bone anchor engaging elements to secure the support to the bone anchor.

11. The orthopedic rod reduction device of any one of claims 6 to 9, wherein the bone anchor engaging portion of the support includes a substantially tubular body which extends distally from the proximal head, the distal end of the tubular body comprising one or more bone anchor engaging elements to secure the support to the bone anchor.

12. The orthopedic rod reduction device of any one of claims 2 to 11, wherein the spring extends from a proximal end to a distal end within the internal lumen of the drive shaft and wherein, the proximal end of the spring engages the lower surface of the drive head.

13. The orthopedic rod reduction device of any one of claims 2 to 12, wherein the distal end of the drive shaft engages the rod engagement element.

14. The orthopedic rod reduction device of claim 13, wherein the rod engagement element includes a base member having a proximal facing surface, a distal facing surface and a spring engagement element which extends from the proximal facing surface and extends into the internal lumen of the drive shaft to engage the distal end of the spring.

15. The orthopedic rod reduction device of claim 14, wherein the spring comprises a helically wound spring member which engages at its proximal end to the drive head and at its distal end to the rod engagement element and which is moveable between a first natural state and a second energy absorbing state, wherein rotation of the drive head and the subsequent linear movement of the drive head causes compression of the spring between the drive head and the rod engagement element to cause the spring to move to its second energy absorbing state.

16. The orthopedic rod reduction device of claim 15, wherein the second energy absorbing state of the spring is achieved by a pre-determined number of rotations of the drive head, said pre-determined number of rotations effecting a pre-determined translational movement of the drive head.

17. The orthopedic rod reduction device of claim 16, wherein further rotations of the drive head beyond the pre-determined number of rotations effects a distal linear movement of the rod engagement element.

18. The orthopedic rod reduction device of any one of claims 14 to 17, wherein the distal facing surface of the rod engagement member comprises a recessed portion shaped to conform to a curved outer surface of the rod.

19. An orthopedic bone rod reduction assembly comprising:

a support comprising a proximal head having a threaded passage therethrough and a bone anchor engaging portion extending from the proximal head;

an actuator comprising a drive head and an elongate drive shaft extending therefrom;

a bone rod engagement element for engaging with and moving the bone rod, the bone rod engagement element comprising a base member and a spring engagement element,

a spring extending from a first end which engages the drive head to a second end which engages the spring engagement element of the rod engagement element, wherein the spring is moveable from a natural state to a compressed state by rotation of the drive head relative to the support;

wherein the spring is moved to its compressed state by a pre-determined number of rotations of the drive head after which, further rotation of the drive head causes a linear movement of the bone rod engagement element.

20. An orthopedic rod reduction device comprising:

an actuator having a first drive head and a second drive head, a drive shaft extending between said first and second drive heads;

a rod engagement element for engaging a rod and moving the rod upon movement of the actuator, and

a spring positioned between the second drive head of the actuator and the rod engagement element.

21. The orthopedic rod reduction device of claim 20, wherein the first drive head has an upper and a lower opposed surface and the drive shaft extends from a proximal end connected to the lower surface of the head member to a distal end which is connected to the second drive head.

22. The orthopedic rod reduction device of claim 21, wherein the second drive head comprises a lower spring engaging surface.

23. The orthopedic rod reduction device of any one of claims 20 to 22, wherein a length of the drive shaft includes a threaded outer surface.

24. The orthopedic rod reduction device of any one of claims 20 to 23, further comprising a support having a proximal head to receive at least part of the actuator and a bone anchor engaging portion, wherein the proximal head includes a passage defined by at least a partially threaded portion of an internal wall of the proximal head, said passage configured to receive at least a length of the drive shaft.

25. The orthopedic rod reduction device of claim 24, wherein the actuator is rotatably moveable to effect an initial linear movement of the actuator relative to the support.

26. The orthopedic rod reduction device of any one of claims 22 to 25, wherein the spring extends from a proximal end which engages the lower spring engaging surface of the second drive head to a distal end which engages the rod engagement element.

27. The orthopedic rod reduction device of claim 26, wherein the spring comprises a helically wound spring member and is moveable between a first natural state and a second energy absorbing state, wherein rotation of the drive head causes linear movement of the second drive head to compress the spring between the second drive head and the rod engagement element and thus cause the spring to move to its second energy absorbing state.

28. The orthopedic rod reduction device of claim 27, wherein the second energy absorbing state of the spring is achieved by a pre-determined number of rotations of the first drive head.

29. The orthopedic rod reduction device of claim 28, wherein further rotations of the drive head beyond the pre-determined number of rotations effects distal linear movement of the rod engagement element.

30. The orthopedic rod reduction device of any one of claims 20 to 29, wherein the rod engagement member comprises a distal rod engaging surface which includes a recessed portion shaped to conform with a curved outer surface of the rod.

31. The orthopedic rod reduction device of any one of claims 24 to 30, wherein the bone anchor engaging portion of the support engages the second drive head and the rod engagement element.

32. The orthopedic rod reduction device of claim 31, wherein the bone anchor engaging portion comprises a plurality of legs which extend from the proximal head and through respective passages in the second drive head and the rod engagement element.

33. An orthopedic bone rod reduction assembly comprising:

a support comprising a proximal head having a threaded passage therethrough and a bone anchor engaging portion extending from the proximal head;

an actuator comprising a first drive head, a second drive head and an elongate drive shaft extending therebetween;

a bone rod engagement element for engaging with and moving the bone rod, the bone rod engagement element comprising a base member and a spring engagement element,

a spring extending from a first end which engages the second drive head to a second end which engages the spring engagement element of the rod engagement element, wherein the spring is moveable from a natural state to a compressed state by rotation of the first drive head relative to the support;

wherein the spring is moved to its compressed state by a pre-determined number of rotations of the first drive head after which, further rotation of the first drive head causes a linear movement of the bone rod engagement element.

34. A method of supporting the spinal column of a patient including:

providing a plurality of rod reduction devices, wherein each rod reduction device comprises;

an actuator having a drive surface;

a rod engagement element for engaging a rod and moving the rod upon movement of the actuator, and

a spring member positioned between the drive surface of the actuator and the rod engagement element;

actuating the actuator to cause the rod engagement element to advance the rod towards a bone anchor, and

maintaining a controlled force between the rod engagement element and the rod upon movement of the rod relative to the actuator.

35. The method of claim 34, wherein the device further comprises a support having a proximal head and the actuator comprises a drive head and a drive shaft extending therefrom, the drive shaft extendable from a proximal end which engages the drive head to a distal end which engages the rod engagement element through a passage in the proximal head of the support;

and

wherein the step of actuating the actuator comprises a first actuating step of rotating the drive head relative to the support to effect a linear movement of the drive head and drive shaft relative to the support.

36. The method of claim 35, wherein the spring comprises a helical coil extending from a proximal end which engages the drive head to a distal end which engages part of the rod engagement element, the helical coil moveable from a natural state to a compressed state upon rotation of the drive head and wherein the first actuating step of rotation of the drive head causes compression of the spring between the drive head and the rod engagement element.

37. The method of claim 36, wherein the spring is caused to move to its compressed state by a pre-determined number of rotations of the drive head.

38. The method of claim 37, wherein the step of actuating the actuator includes a second actuating step wherein further rotation of the drive head beyond the pre-determined number causes a distal linear movement of the rod engagement element which in turn causes the rod to move towards the bone anchor.