Spine stabilization system with dynamic screw
A spine stabilization system having a dynamic screw comprises at least one bone anchor assembly comprising a receiver member and a bone engaging member. In one embodiment, the bone engaging member is a screw shank extending from the receiver member. A rod is connected to the receiver member. In one embodiment, the rod comprises a ball-shaped member that engages a bearing surface provided within a cavity of the receiver member. In this embodiment, the rod is pivotably connected to the receiver member. In one such embodiment, a central axis defined by the rod pivots about a pivot point located on the central axis when the rod pivots relative to the receiver member. Accordingly, the pivot point for the rod may be provided within the cavity of the receiver member. The rod may be a fixed length or adjustable to accommodate different segmental units and patients of different sizes.
1 . A spine stabilization system configured for connection between vertebrae, the spine stabilization system comprising:
a) at least one bone anchor assembly comprising a bone engaging member; and
b) an elongated connecting member pivotably connected to the bone engaging member of the at least one bone anchor assembly, wherein the elongated connecting member defines an axis that extends along the elongated connecting member and the axis pivots about a pivot point on the axis when the elongated connecting member pivots relative to the bone engaging member.
2 . The spine stabilization system of claim 1 wherein the elongated connecting member is adjustable in length.
3 . The spine stabilization system of claim 1 wherein the at least one bone anchor assembly further comprises a receiver member engaging both the elongated connecting member and the bone engaging member.
4 . The spine stabilization system of claim 3 wherein the elongated connecting member is pivotably connected to the receiver member.
5 . The spine stabilization system of claim 3 wherein the elongated connecting member is fixedly connected to the receiver member.
6 . The spine stabilization system of claim 3 wherein the receiver member is pivotably connected to the bone engaging member.
7 . The spine stabilization system of claim 3 wherein the receiver member is fixedly connected to the bone engaging member.
8 . The spine stabilization system of claim 1 wherein the bone engaging member comprises a shank.
9 . The spine stabilization system of claim 8 wherein the bone engaging member further comprises a head.
10 . The spine stabilization system of claim 9 wherein the head is a screw head and the shank is a threaded screw shank.
11 . A spine stabilization system configured for connection between vertebrae, the spine stabilization system comprising:
a) at least one bone engaging member;
b) at least one receiver member pivotably connected to a portion of the bone engaging member; and
c) an elongated connecting member pivotably connected to the at least one receiver member.
12 . The spine stabilization system of claim 11 wherein the elongated connecting member defines an axis and the axis pivots about a pivot point when the elongated connecting member pivots relative to the receiver member.
13 . The spine stabilization system of claim 12 wherein the pivot point is located within the receiver member.
14 . The spine stabilization system of claim 12 wherein the axis is a central axis and the pivot point is located along the central axis.
15 . The spine stabilization system of claim 11 wherein the elongated connecting member includes a shaft having an elastic central portion.
16 . The spine stabilization system of claim 14 wherein the elongated connecting member is an adjustable length rod.
17 . The spine stabilization system of claim 16 wherein the rod includes a shaft having at least one adjustable end.
18 . The spine stabilization system of claim 17 wherein the at least one adjustable end includes a post configured to slide within the shaft in order to provide a telescoping rod.
19 . The spine stabilization system of claim 17 wherein the at least one adjustable end is configured to threadedly engage the shaft.
20 . The spine stabilization system of claim 19 wherein a ball is provided on the at least one adjustable end, and rotation of the ball effectively lengthens or shortens the rod.
21 . The spine stabilization system of claim 17 wherein the shaft or the at least one adjustable end is comprised of a shape memory alloy.
22 . The spine stabilization system of claim 12 wherein the at least one receiver member comprises a cavity configured to receive the elongated connecting member.
23 . The spine stabilization system of claim 22 further comprising a bearing positioned within the cavity and configured to engage the elongated connecting member.
24 . The spine stabilization system of claim 22 wherein the pivot point is located within the cavity.
25 . The spine stabilization system of claim 11 wherein the at least one bone engaging member comprises a first bone engaging member and a second bone engaging member, wherein the at least one receiver member comprises a first receiver member and a second receiver member, wherein the elongated connecting member extends between the first receiver member and the second receiver member, and wherein the elongated connecting member is pivotably connected to both the first receiver member and the second receiver member.
26 . The spine stabilization system of claim 25 wherein the elongated connecting member is configured for extension or compression, and wherein movement of the first bone engaging member relative to the second bone engaging member causes compression or extension of the elongated connecting member.
27 . The spine stabilization system of claim 11 wherein the at least one bone engaging member comprises a bone screw including a screw head and a screw shank, wherein the screw head is pivotably connected to the receiver member.
28 . A spine stabilization system comprising:
a) at least one bone engaging member;
b) an elongated connecting member pivotably connected to the at least one bone engaging member;
c) a pivot member fixed to the elongated connecting member; and
d) a receiver member connected to the at least one bone engaging member, the receiver member configured to engage the pivot member such that the pivot member is pivotable within the receiver member.
29 . The spine stabilization system of claim 28 wherein the pivot member is integral with the elongated connecting member.
30 . The spine stabilization system of claim 28 wherein the pivot member is clamped onto the elongated connecting member.
31 . The spine stabilization system of claim 28 wherein the pivot member is a ball-shaped member.
32 . The spine stabilization system of claim 28 wherein the receiver member is fixed to the at least one bone engaging member.
33 . The spine stabilization system of claim 28 wherein the receiver member is pivotably connected to the at least one bone engaging member.
34 . The spine stabilization system of claim 28 wherein the bone engaging member comprises a shank extending from the receiver member.