Pedicle screw constructs and spinal rod attachment assemblies
View Patent ↗Spine fixation constructs are configured to receive and retain a spinal rod onto a vertebral bone screw. The spine fixation constructs provide for 360° rotation about a bone screw and variable axial placement about the bone screw. In one form, a rod holder of the spine fixation construct is configured to be axially received onto the bone screw. Axial positioning of the rod holder on the bone screw is fixed through cooperation of the rod holder with a fixation component. The fixation component is axially received onto the bone screw. Retention of the spinal rod by the spinal rod holder is also provided via the fixation member. In one form, spinal rod retention is provided upon axial retention of the spinal rod holder onto the bone screw through cooperating action between the fixation mechanism and the spinal rod holder. According to an embodiment, a member of the rod holder is caused to pivot and capture the spinal rod upon receipt of the fixation member onto the bone screw and rod holder. According to another embodiment, pivoting motion of a pawl of the rod holder by the fixation member not only locks the spinal rod but skews the pawl relative to the bone screw to wedge the axial placement of the pawl and thus the rod holder relative to the bone screw.
1. A spine fixation construct for receiving and retaining a spinal rod onto a bone screw, the spine fixation construct comprising:
a rod holder configured to be axially received and positioned onto the bone screw and to receive and lock onto a spinal rod when engaged, the rod holder comprising:
a connector having a pair of spaced apart prongs to receive the spinal rod and define a slot therebetween;
a pawl at least partially disposed in the slot between the prongs and pivotally coupled to the connector to pivot within the slot between the prongs;
a fixation component configured to be axially received on the bone screw and the rod holder,
wherein engagement of the rod holder by the fixation component pivots the pawl into an engagement with both the spinal rod and the bone screw;
wherein the connector comprises an annular bore to axially receive the bone screw;
wherein the pawl is pivotally attached to the connector via a pivot pin extending between the prongs and parallel to the spinal rod; and
wherein the fixation component threadably engages the annular bore in the connector.
2. The spine fixation construct of claim 1 , wherein the pawl defines a contact surface that is abutted by the fixation component to cause pivoting of the pawl.
3. The spine fixation construct of claim 2 , wherein the pawl defines a lip that at least partially wraps around the spinal rod when the rod holder is engaged by the fixation component.
4. The spine fixation construct of claim 1 , wherein the pawl defines a lip that at least partially wraps around the spinal rod when the rod holder is engaged by the fixation component.
5. The spine fixation construct of claim 4 , wherein both the prongs and the lip of the pawl extend upwardly.
6. A spine fixation construct for receiving and retaining a spinal rod, the spine fixation construct comprising: a bone screw having a threaded shank and a head, and defining a longitudinal axis;
a fixation nut; and
a rod holder assembly configured to be axially adjustably received onto the bone screw, the rod holder assembly having a connector and a pivot member configured to pivot relative to the connector and the spinal rod, the pivot member having a concave inner surface that contacts and at least partially wraps around the spinal rod;
wherein the fixation nut threadably engages an annular first bore in the connector and engages the pivot member to pivot the pivot member to engage and lock the spinal rod relative to the connector and engage and lock the bone screw relative to the connector.
7. The spine fixation construct of claim 6 , wherein the connector includes a spinal rod retention area for receiving the spinal rod and a channel in communication with the spinal rod retention area; and
wherein the pivot member is disposed in the channel and pivotally attached to the connector to abut and lock onto the spinal rod in the spinal rod retention area when pivoted by the fixation nut as the fixation nut engages the rod holder assembly.
8. The spine fixation construct of claim 7 , wherein the pivot member comprises a body and an upwardly extending flange, the upwardly extending flange configured to at least partially wrap around the spinal rod.
9. The spine fixation construct of claim 8 , wherein the pivot member defines a second bore that receives the bone screw, and wherein pivoting of the pivot member causes the second bore to engage and lock the bone screw relative to the connector.
10. The spine fixation construct of claim 6 , wherein the connector includes an annular bore for reception by the bone screw and a pair of spaced apart prongs, the pair of spaced apart prongs defining a spinal rod retention area for receiving the spinal rod and a slot in communication with the spinal rod retention area; and
wherein the pivot member is disposed in the slot and pivotally attached to the connector via a pivot pin extending through the prongs and the pivot member, the pivot member is configured to abut and lock onto the spinal rod in the spinal rod retention area when pivoted by the fixation nut as the fixation nut engages the rod holder assembly.
11. The spine fixation construct of claim 10 , wherein the pivot member defines a contact surface that is abutted by the fixation nut to cause pivoting of the pivot member.
12. The spine fixation construct of claim 11 , wherein the pivot member defines a lip that surrounds the spinal rod when the rod holder assembly is engaged by the fixation nut.
13. A spine fixation construct comprising:
a bone screw having a threaded shank and a head, and defining a longitudinal axis;
a rod holder configured to be axially received and positioned onto the head of the bone screw and to receive and lock onto a spinal rod, the rod holder having a connector and a pawl coupled to the connector by a pivot pin, the pivot pin generally perpendicular to the longitudinal axis; and
a fixation device configured to be both axially received on the head of the bone screw and by the connector, the fixation device further configured to pivot the pawl to lock the spinal rod relative to the rod holder;
wherein the fixation device threadably engages an annular bore in the connector.
14. The spine fixation construct of claim 13 , wherein the connector includes a spinal rod retention area for receiving the spinal rod and a channel in communication with the spinal rod retention area; and
a pawl disposed in the channel and pivotally attached to the connector, the pawl configured to abut and lock onto the spinal rod in the spinal rod retention area when pivoted by the fixation device as the fixation device engages the rod holder.
15. The spine fixation construct of claim 14 , wherein the pawl defines a contact surface that is abutted by the fixation device to cause pivoting of the pawl.
16. The spine fixation construct of claim 15 , wherein the pawl defines a lip that surrounds the spinal rod when the rod holder is engaged by the fixation device.
17. The spine fixation construct of claim 14 , wherein the pawl includes a first portion that directly engages the spinal rod and a second portion separate from the first portion that directly engages the bone screw.
18. The spine fixation construct of claim 17 , wherein the first portion comprises a curved contact surface that at least partially wraps around the spinal rod.
19. The spine fixation construct of claim 18 , wherein the second portion comprises a bore to axially receive the bone screw.
20. The spine fixation construct of claim 13 , wherein the connector includes a pair of spaced apart prongs and an annular bore for reception by the bone screw, the pair of spaced apart prongs defining a spinal rod retention area for receiving the spinal rod and a slot in communication with the spinal rod retention area; and
wherein the pivot pin extends through the pawl between the two spaced apart prongs.
21. The spine fixation construct of claim 20 , wherein the pawl defines a contact surface that is abutted by the fixation device to cause pivoting of the pawl.