Pedicle Screw Assembly and Dynamic Spinal Stabilization Devices Incorporating the Pedicle Screw Assembly
AssigneeColorado State University Research Foundation
InventorsChristian M. Puttlitz, Benjamin C. Gadomski
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Abstract
A dynamic spinal stabilization device for the treatment of high-grade spinal disorders is disclosed herein. The dynamic spinal stabilization device includes two or more screw assemblies, each of which include a pedicle screw and a head socket containing a curved internal track that limits the range of motion and center of rotation of the spinal segments stabilized using the device to the physiological levels of a nondegraded spinal segment.
Claims21
A screw assembly for use in a dynamic spinal stabilization device, the screw assembly comprising:
- a head socket comprising a lower face containing a slot extending diametrically across a central portion of the lower face, and further extending upward between the lower face and a curved lower cavity surface of an upper cavity of the head socket;
- a lock comprising an exposed upper lock surface and a curved lower lock surface, wherein the lock is to be placed in the head socket over the curved lower cavity surface to form an internal curved groove between the curved lower lock surface and the curved lower cavity surface;
- and
- a pedicle screw comprising a screw head to be retained within the internal curved groove and a screw neck to extend downward from the screw head through the slot;
- wherein, when the screw head is retained within the internal curved groove, the screw head freely slides along the internal curved groove along a range of movement limited by a length of the slot, and a center of rotation of the pedicle screw is situated at a distance downward from the screw head that is equal to a radius of curvature of the internal curved groove.
A method of assembling a screw assembly, the method comprising:
- inserting a bottom portion of a pedicle screw downwardly through a slot in a lower face of a head socket until a screw neck extending downward from a screw head of the pedicle screw extends through the slot, the slot extending diametrically across a central portion of the lower face, the slot further extending upward between the lower face and a curved lower cavity surface of an upper cavity of the head socket;
- and
- placing a lock comprising an exposed upper lock surface and a curved lower lock surface in the head socket over the curved lower cavity surface to form an internal curved groove between the curved lower lock surface and the curved lower cavity surface, the screw head of the pedicle screw to be retained within the internal curved groove;
- wherein, when the screw head is retained within the internal curved groove, the screw head freely slides along the internal curved groove along a range of movement limited by a length of the slot, and a center of rotation of the pedicle screw is situated at a distance downward from the screw head that is equal to a radius of curvature of the internal curved groove.
Dependencies are inferred from the claim text.