OFFSET DYNAMIC MOTION SPINAL STABILIZATION SYSTEM
Provided is an offset dynamic motion system. In one example, the system includes an offset member having a rod connecting a shaped portion to a threaded portion, where a longitudinal axis of the threaded portion is angled relative to a longitudinal axis of the rod and the shaped portion is configured to couple to a polyaxial head. A first dynamic member is configured to rotationally couple to another polyaxial head. A second dynamic member is configured to rotationally couple to the threaded end of the offset member and to slideably receive part of the first dynamic member.
1 . A dynamic stabilization device having an integrated offset comprising:
a first member having first and second portions aligned along a longitudinal axis, wherein the first portion is configured to rotationally couple to a first polyaxial head and includes a first intersecting axis that extends through the first portion at an angle to the longitudinal axis to intersect a center point; and
a second member having a third portion aligned along the longitudinal axis and slideably engaging the second portion, and a fourth portion offset from the longitudinal axis and configured to rotationally couple to a second polyaxial head, the fourth portion including a second intersecting axis that extends through the fourth portion at an angle to the longitudinal axis to intersect the center point, wherein the longitudinal axis is curved to maintain the intersection of the first and second intersecting axes with the center point as the center point moves along a curved three dimensional surface during movement of the first member relative to the second member.
2 . The dynamic stabilization device of claim 1 wherein the fourth portion is offset from the longitudinal axis at a substantially ninety degree angle.
3 . The dynamic stabilization device of claim 1 further comprising a neck coupling the third portion to the fourth portion.
4 . The dynamic stabilization device of claim 1 wherein the third portion includes a bore oriented along the longitudinal axis and the fourth portion includes a bore oriented substantially perpendicularly to the longitudinal axis.
5 . A dynamic stabilization system having an offset member for a single dynamic device comprising:
an offset member having a rod connecting a shaped first portion to a threaded second portion, wherein a first longitudinal axis of the threaded second portion is angled relative to a second longitudinal axis of the rod, and wherein the shaped first portion is configured to couple to a first polyaxial head;
a first dynamic member having first and second portions oriented along a third longitudinal axis, wherein the first portion is configured to rotationally couple to a second polyaxial head and includes a first intersecting axis that extends through the first portion at an angle to the third longitudinal axis to intersect a center point; and
a second dynamic member having third and fourth portions oriented along the third longitudinal axis, wherein the third portion is configured to rotationally couple to the threaded second end of the offset member and includes a second intersecting axis that extends through the third portion at an angle to the third longitudinal axis and along the first longitudinal axis of the threaded second end to intersect the center point, wherein the fourth portion is configured to slideably receive the second portion, and wherein the first and second dynamic members are configured to maintain the intersection of the first and second intersecting axes with the center point as the center point moves along a curved three dimensional surface during movement of the first dynamic member relative to the second dynamic member.
6 . The dynamic stabilization system of claim 5 wherein the shaped first portion is substantially spherical.
7 . The dynamic stabilization system of claim 5 wherein a position of the third portion is adjustable along the threaded second portion.
8 . The dynamic stabilization system of claim 5 wherein the first portion is configured to rotationally couple to the second polyaxial head by means of another offset member having a second rod connecting a shaped third portion to a threaded fourth portion, wherein the shaped third portion is coupled to the second polyaxial head and the threaded fourth portion is coupled to the first portion.
9 . The dynamic stabilization system of claim 8 wherein a position of the first portion is adjustable along the threaded fourth portion.
10 . The dynamic stabilization system of claim 5 wherein the rod is curved.
11 . The dynamic stabilization system of claim 5 wherein the first longitudinal axis of the threaded second portion is substantially perpendicular to the second longitudinal axis of the rod.
12 . A dynamic stabilization system having an offset member for multiple dynamic devices comprising:
an offset member having a rod with a first end coupled to a first polyaxial head, a second end coupled to a second polyaxial head, and first and second threaded extensions extending substantially perpendicularly to a longitudinal axis of the rod between the first and second ends;
a first dynamic device having a first member rotatably coupled to the first threaded extension and slideably engaged to a second member of the first dynamic device that is coupled to a third polyaxial head, wherein movement of the first member relative to the second member and the offset member defines movement of a first center point along a first curved three dimensional surface; and
a second dynamic device having a third member rotatably coupled to the second threaded extension and slideably engaged to a fourth member of the second dynamic device that is coupled to a fourth polyaxial head, wherein movement of the third member relative to the fourth member and the offset member defines movement of a second center point along a second curved three dimensional surface.
13 . The dynamic stabilization system of claim 12 wherein the first and second threaded extensions are positioned on a side of the rod opposite the first and second polyaxial heads.
14 . The dynamic stabilization system of claim 12 wherein the rod is curved.
15 . The dynamic stabilization system of claim 12 wherein the first and second center points are identical.
16 . The dynamic stabilization system of claim 12 wherein the first and second curved three dimensional surfaces are identical.
17 . The dynamic stabilization system of claim 12 wherein the second and fourth members are coupled to the third and fourth polyaxial heads, respectively, by means of a second offset member.
18 . The dynamic stabilization system of claim 17 wherein the second offset member includes a second rod with a third end coupled to the third polyaxial head, a fourth end coupled to the fourth polyaxial head, and third and fourth threaded extensions coupled to the second and fourth members, respectively.
19 . The dynamic stabilization system of claim 12 wherein the second member is coupled to the third polyaxial head by means of a second offset member.
20 . The dynamic stabilization system of claim 19 wherein the second offset member includes a second rod connecting a shaped first portion to a threaded second portion, wherein a longitudinal axis of the threaded second portion is angled relative to a longitudinal axis of the second rod, and wherein the shaped first portion is coupled to the third polyaxial head and the threaded second portion is coupled to the second member.