Spinal implant and methods of use thereof

1. A spinal fixation device comprising:

a housing defining a longitudinal axis;

a bone screw member including a head and a threaded shaft, the head selectively securable within the housing;

a locking ring disposed within the housing, the locking ring biased in a neutral position and radially expandable to a partially expanded position when the head of the bone screw member is positioned therein, the partially expanded position retaining the head of the bone screw member within the housing; and

a crush ring disposed within the housing proximal to the locking ring and adjacent the head of the bone screw member, the crush ring having an initial state and a deformed state when a force is applied thereto, the crush ring pushing against the head of the bone screw member when transitioning from the initial state to the deformed state which expands the locking ring to a fully expanded position to fix the bone screw member to the housing.

2. The spinal fixation device of claim 1 , wherein the bone screw member has a cone of angulation of about 95° relative to the longitudinal axis of the housing.

3. The spinal fixation device of claim 1 , wherein the housing includes a body portion and opposing walls extending proximally from the body portion, the housing divided by a plane that is substantially equidistant from proximal and distal ends of the housing and substantially perpendicular to the longitudinal axis of the housing.

4. The spinal fixation device of claim 3 , wherein the head of the bone screw member is disposed within the body portion of the housing distal to the plane.

5. The spinal fixation device of claim 3 , wherein the crush ring is disposed within the body portion of the housing distal to the plane.

6. The spinal fixation device of claim 4 , wherein the body portion of the housing has an inner surface including relief features defined therein having an outer diameter that is larger than an outer diameter of the locking ring.

7. The spinal fixation device of claim 6 , wherein the locking ring includes engagement features configured to engage the relief features of the housing when the locking ring is expanded.

8. The spinal fixation device of claim 6 , wherein the locking ring includes notches extending longitudinally through portions thereof in spaced relation relative to each other.

9. The spinal fixation device of claim 1 , wherein the crush ring includes a body portion having a flange disposed radially therearound, the flange configured to contact the head of the bone screw member when the head is disposed within the housing.

10. The spinal fixation device of claim 3 , wherein the housing includes a channel defined between the opposing walls thereof, and a proximal end of the crush ring is disposed adjacent to the channel of the housing.

11. The spinal fixation device of claim 1 , wherein a spinal rod is selectively securable to the housing of the spinal fixation device.

12. The spinal fixation device of claim 11 , wherein the spinal rod is positionable within a channel of the housing, the crush ring movable to the deformed state and the locking ring expandable to the fully expanded position when the spinal rod is fully reduced into the channel.

13. A method for aligning vertebral bodies of a spine comprising:

fastening a bone screw member of a spinal fixation device to a vertebral body, the spinal fixation device including:

a housing defining a longitudinal axis;

the bone screw member including a head and a threaded shaft, the head selectively securable within the housing;

a locking ring disposed within the housing, the locking ring biased in a neutral position and radially expandable to a partially expanded position when the head of the bone screw member is positioned therein, the partially expanded position retaining the head of the bone screw member within the housing; and

a crush ring disposed within the housing proximal to the locking ring and adjacent the head of the bone screw member, the crush ring having an initial state and a deformed state when a force is applied to the crush ring, the crush ring pushing against the head of the bone screw member when transitioning from the initial state to the deformed state which expands the locking ring to a fully expanded position to fix the bone screw member to the housing; and

positioning a portion of a spinal rod within a channel defined in the housing of the spinal fixation device.

14. The method of claim 13 , further comprising:

rotating the housing with respect to the bone screw member; and

fully reducing the spinal rod into the channel.

15. The method of claim 14 , wherein rotating the housing includes moving the housing within a cone of angulation of about 95° of the bone screw member relative to the longitudinal axis of the housing.

16. The method of claim 13 , further including assembling the spinal fixation device prior to fastening the bone screw member to the vertebral body.

17. The method of claim 16 , wherein assembling the spinal fixation device includes:

positioning the crush ring within the housing;

positioning the locking ring in the housing; and

inserting the head of the bone screw member into the housing and through the locking ring to couple the bone screw member to the housing.