Pivoting joints for spinal implants including designed resistance to motion and methods of use

Abstract

A pivoting connector couples a vertebral member to a longitudinal member. An anchor is pivotally attached to a body by positioning a head of the anchor within a cavity in the body. A longitudinal rod is inserted into a channel also positioned within the body and axially aligned with the cavity. A retainer applies a force to maintain the longitudinal rod within the channel, however the force may be isolated from the anchor. One embodiment may include a compression member that is separate from or integral with the body. The compression member may transmit a rod securing force to the anchor to secure or limit the pivoting movement of the anchor member relative to the body. The compression member may deflect or detach under the influence of the securing force.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are perspective views of a pivoting head assembly according to one or more embodiments comprising a longitudinal member attached to the spine;

FIGS. 2A and 2B are perspective views of a pivoting head coupled to an anchor member according to one embodiment;

FIG. 3 is a side section view of a pivoting head coupled to an anchor member and securing a longitudinal member according to one embodiment;

FIG. 4 is a perspective view of an anchor member for use with a pivoting head according to one embodiment;

FIGS. 5A-5D are top section views of a pivoting head with an anchor member and wear member inserted therein according to different embodiments;

FIGS. 6A and 6B are perspective views of a wear member for use with a pivoting head according to one embodiment;

FIG. 7 is a side view, including a partial section view, of an assembled anchor member and wear member for use with a pivoting head according to one embodiment;

FIG. 8 is a side section view of a pivoting head with an anchor member and wear member inserted therein according to one embodiment;

FIG. 9 is a side section view of an assembled pivoting head with an anchor member and wear member constrained therein according to one embodiment;

FIG. 10 is a detailed section view of the bottom region of a pivoting head according to one embodiment;

FIG. 11 is a side section view of a pivoting head and various wear members that may be used with the pivoting head according to one embodiment;

FIG. 12 is a side section view of an assembled pivoting head with an anchor member and wear member constrained therein according to one embodiment;

FIG. 13 is a detailed section view of the bottom region of a pivoting head according to one embodiment;

FIG. 14 is a detailed section view of the bottom region of a pivoting head according to one embodiment;

FIG. 15 is a detailed section view of an interference snap ring that may be used with the pivoting head according to one embodiment;

FIG. 16 is a perspective view of a pivoting head coupled to an anchor member according to one embodiment;

FIG. 17 is a side section view of an assembled pivoting head with an anchor member and wear member constrained therein according to one embodiment;

FIG. 18 is a side section view of an assembled pivoting head with an anchor member and wear member constrained therein according to one embodiment;

FIG. 19 is a perspective view of a wear member for use with a pivoting head according to one embodiment;

FIG. 20 is a side section view of an assembled pivoting head with an anchor member and wear member constrained therein according to one embodiment;

FIG. 21 is a side section view of an assembled pivoting head with an anchor member and wear member constrained therein according to one embodiment;

FIGS. 22A and 22B, respectively, are exploded and unexploded side section views of a pivoting head with a crown member inserted therein according to one embodiment;

FIG. 23 is a lower perspective view of a pivoting head coupled to an anchor member according to one embodiment;

FIG. 24 is an upper perspective view of a pivoting head coupled to an anchor member according to one embodiment;

FIG. 25 is a side section view of a pivoting head with a crown member and anchor head retained therein according to one embodiment;

FIGS. 26A and 26B are side section views of a pivoting head with a deflectable crown member and anchor head retained therein according to one embodiment;

FIGS. 27A and 27B are side section views of a pivoting head with a detachable crown member and anchor head retained therein according to one embodiment; and

FIGS. 28A-D illustrate exemplary process steps by which a crown member and anchor head may be retained within a pivoting head according to one embodiment.

Claims

1. A connector to connect a vertebral member to a longitudinal member, the connector comprising: an anchor comprising a shaft and an anchor head;a body attached to the anchor and comprising a channel and a cavity aligned along a common axis, the channel sized to receive the longitudinal member, the channel and the cavity formed on opposite sides of the body;a fastener configured to maintain the longitudinal member in the channel; anda compression element contained within the cavity and forming a receiving area to accommodate the head of the anchor, the compression element at least partially extending into the channel to contact the longitudinal member so that the compression element is displaced into contact with the anchor head by the longitudinal member when the fastener maintains the longitudinal member in the channel,the body including a deformable sidewall that is moveable between a first state in which the anchor head is insertable into the cavity and a second state in which the compression element and the anchor head are retained in the cavity.

2. The connector of claim 1 wherein the compression element is a distinct member separate from the body and the anchor, the compression element being insertable into the cavity when the deformable sidewall is in the first state.

3. The connector of claim 1 wherein the compression element is formed as a part of the body.

4. The connector of claim 3 wherein the compression element is elastically deformable when displaced into contact with the anchor head by the longitudinal member when the fastener maintains the longitudinal member in the channel.

5. The connector of claim 3 wherein at least a portion of the compression element yields relative to the body when displaced into contact with the anchor head by the longitudinal member when the fastener maintains the longitudinal member in the channel.

6. The connector of claim 5 wherein the compression element separates from the body when displaced into contact with the anchor head by the longitudinal member when the fastener maintains the longitudinal member in the channel.

7. A connector to connect a vertebral member to a longitudinal member, the connector comprising: an anchor comprising a shaft and an anchor head;a body attached to the anchor and comprising a saddle including a channel formed between a pair of upright arms, the channel sized to receive the longitudinal member;a fastener configured to maintain the longitudinal member in the channel; anda compression element formed as a part of the body and suspended between the upright arms, the compression element extending into the channel to contact the longitudinal member when the fastener maintains the longitudinal member in the channel, the compression element forming a receiving area opposite the channel to accommodate the head of the anchor,the longitudinal member displacing the compression element into contact with the anchor head when the fastener maintains the longitudinal member in the channel.

8. The connector of claim 7 wherein the compression element is elastically deformable when displaced by the longitudinal member.

9. The connector of claim 7 wherein the compression element is plastically deformable when displaced by the longitudinal member.

10. The connector of claim 7 wherein the compression element separates from the body when displaced by the longitudinal member.

11. The connector of claim 7 wherein a connection point between the compression element and the body yields when the compression element is displaced by the longitudinal member.

12. The connector of claim 7 wherein the anchor head is retained within a cavity in the body that is disposed opposite the channel.

13. A method of connecting a vertebral anchor to a longitudinal rod receptacle, the method comprising the steps of: pivotally attaching the vertebral anchor to a body by positioning a head of the vertebral anchor within a receiving area of a compression member disposed within a cavity in the body, the body further including a channel to receive a longitudinal rod, the longitudinal rod contacting the compression member when the longitudinal rod is secured within the channel by a retaining member;adjusting the cavity from a first size that allows the head of the vertebral anchor to enter the cavity from outside the body to a second size that retains the head of the vertebral anchor within the cavity.

14. The method of claim 13 further comprising inserting the compression member into the cavity prior to the step of positioning the head of the vertebral anchor within the receiving area.

15. The method of claim 13 wherein the compression member is a separate member distinct from the body.

16. The method of claim 13 wherein the compression member is formed as a part of the body.

17. A method of connecting a vertebral member to a longitudinal rod, the method comprising the steps of: securing an anchor member to the vertebral member;orienting a body that is pivotally attached to the vertebral anchor by placing a head of the vertebral anchor in sliding contact with a compression member that is formed into a wall that surrounds a cavity in the body;positioning the compression element to extend into a channel in the body;inserting the longitudinal rod into the channel and into contact with the compression element;applying a force to maintain the longitudinal rod within the channel; anddisplacing the compression element into contact with the head when the force maintains the longitudinal rod within the channel.

18. The method of claim 17 wherein the step of orienting the body that is pivotally attached to the vertebral anchor positions the compression element to extend into the channel in the body.

19. The method of claim 17 wherein the step of displacing the compression element into contact with the head comprises elastically deforming the compression element.

20. The method of claim 17 wherein the step of displacing the compression element into contact with the head comprises plastically deforming the compression element.

21. The method of claim 17 wherein the step of displacing the compression element into contact with the head comprises separating the compression element from the walls forming the cavity in the body.

22. The method of claim 17 wherein the step of displacing the compression element into contact with the head when the force maintains the longitudinal rod within the channel further comprises locking the orientation of the body relative to the anchor member.

23. The method of claim 17 wherein the step of displacing the compression element into contact with the head when the force maintains the longitudinal rod within the channel further comprises increasing a resistance of the sliding contact between the anchor member and the compression member.

24. A method of connecting a vertebral anchor to a longitudinal rod receptacle, the method comprising the steps of: pivotally attaching the vertebral anchor to a body by positioning a head of the vertebral anchor within a cavity in the body, the body further including a channel to receive a longitudinal rod;adjusting the cavity from a first size that allows the head of the vertebral anchor to enter the cavity from outside the body to a second size that retains the head of the vertebral anchor within the cavity.

25. The method of claim 24 wherein the step of positioning a head of the vertebral anchor within a cavity in the body further comprises placing the head of the vertebral body within a receiving area of a compression member that is sized to fit within the cavity.

26. The method of claim 25 further comprising placing the head of the vertebral body within the receiving area of the compression member prior to positioning the head of the vertebral anchor and the compression member within the cavity in the body.

27. The method of claim 25 wherein the longitudinal rod contacts the compression member when the longitudinal rod is secured within the channel by a retaining member.

28. The method of claim 25 wherein the longitudinal rod is separated from the compression member when the longitudinal rod is secured within the channel by a retaining member.

29. The method of claim 25 further comprising inserting the compression member into the cavity prior to the step of positioning the head of the vertebral anchor within the receiving area.

30. The method of claim 25 wherein the compression member is formed as a part of the body.

31. The method of claim 24 further comprising securing the body in a holding fixture and the step of adjusting the cavity from the first size to the second size comprises deforming the body to retain the retain the head of the vertebral anchor within the body.

32. The method of claim 31 wherein the step of deforming the body comprises orbital forming the body.

33. The method of claim 31 wherein the step of deforming the body comprises cold forming the body.

34. The method of claim 31 wherein the step of deforming the body comprises hot forming the body.