Spinal rod connector assembly
A spinal rod connector assembly for use with a vertebral bone screw has an articulating clamp for 1) fixing an orientation of the spinal rod connector assembly relative to and on the vertebral bone screw, and 2) attaching a separate spinal rod onto the spinal rod connector assembly in concert with one another. The articulating clamp resides in a body of the spinal rod connector assembly and transfers a received downward force laterally to a spinal rod component of the spinal rod connector assembly which is configured to abut the spinal rod and hold the spinal rod between itself and a spinal rod holder of the spinal rod connector assembly. The articulating clamp thus improves the force transfer efficacy of the system.
1. A spinal rod connector assembly for receipt on a vertebral bone screw, the spinal rod connector assembly comprising:
a body defining an internal cavity, an upper opening in communication with the internal cavity, a lower opening in communication with the internal cavity, a lateral opening in communication with the internal cavity, and axially aligned first and second pivot bores in communication with the internal cavity;
an articulating member situated in the internal cavity of the body, the articulating member defining first and second hemispherical cutouts, wherein the articulating member is configured to a) clamp onto a head of a vertebral bone screw received through the lower opening to fix orientation of the body relative to the head of the vertebral bone screw, and b) expand in a radial direction, both upon receipt of a downward force exerted on the articulating member;
a first pivot pin received by the first pivot bore and the first hemispherical cutout;
a second pivot pin received by the second pivot bore and the second hemispherical cutout;
a spinal rod holder rotatably situated on the body at the lateral opening, the spinal rod holder configured to receive a spinal rod therethrough; and
a spinal rod abutment member rotatably situated within the lateral opening of the body and extending into the spinal rod holder;
wherein expansion of the articulating member in response to receipt of a downward force exerted on the articulating member moves the spinal rod abutment member into the spinal rod holder such that the spinal rod abutment surface abuts a spinal rod to fix the spinal rod to the spinal rod holder and fixes rotational orientation of the spinal rod holder.
2. The spinal rod connector assembly of claim 1 , wherein the articulating member is pivotally retained in the internal cavity of the body via the first and second pivot pins.
3. The spinal rod connector assembly of claim 1 , further comprising:
a retaining ring situated about the spinal rod holder adjacent the body, the retaining ring configured to aid in fixing the rotational orientation of the spinal rod holder in response to receipt of the downward force exerted on the articulating member.
4. The spinal rod connector assembly of claim 3 , wherein:
the spinal rod holder includes a first set of teeth situated on an annular end of the spinal rod holder; and
the retaining ring includes a second set of teeth situated on an annular periphery of the retaining ring adjacent the first set of teeth;
wherein the first and second set of teeth mesh in response to receipt of the downward force exerted on the articulating member to thereby fix the rotational orientation of the spinal rod holder.
5. The spinal rod connector assembly of claim 1 , wherein the articulating member includes an upper lip that abuts the spinal rod component in response to receipt of the downward force exerted on the articulating member.
6. The spinal rod connector assembly of claim 5 , wherein the upper lip has a thickness that applies an increase in lateral force against the spinal rod component relative to the downward force exerted on the articulating member.
7. The spinal rod connector assembly of claim 1 , wherein the articulating member has a clasping area at a lower end thereof that is configured to clamp onto the head of the vertebral bone screw.
8. The spinal rod connector assembly of claim 1 , wherein the articulating member has a chamfer on an upper end thereof that is configured to interface with a chamfer of a torque nut.
9. The spinal rod connector assembly of claim 1 , wherein;
the lower opening of the body is tapered; and
a lower end of the articulating member is tapered complementarily to the tapered lower opening of the body.
10. The spinal rod connector assembly of claim 1 , wherein the articulating member pivots about an axis defined by the first and second pivot pins.
11. A spinal rod connector assembly for receipt on a vertebral bone screw, the spinal rod connector assembly comprising:
a generally rectangular body defining an internal cavity, an upper threaded bore in communication with the internal cavity, a lower bore in communication with the internal cavity, a lateral bore in communication with the internal cavity, and a first pivot bore in communication with the internal cavity;
an articulating member situated in the internal cavity of the body, the articulating member defining a first hemispherical cutout, wherein the articulating member is configured to a) clamp onto a head of a vertebral bone screw received through the lower bore to fix orientation of the body relative to the head of the vertebral bone screw, and b) expand in a radial direction, both upon receipt of a downward force exerted on the articulating member via a threaded nut received in the upper threaded bore;
a first pivot pin received by the first pivot bore and the first hemispherical cutout;
a spinal rod holder rotatably situated at the lateral bore, the spinal rod holder configured to receive a spinal rod therethrough; and
a spinal rod abutment member rotatably at least partially situated within the lateral bore of the body and extending into the spinal rod holder, the spinal rod abutment member having a first end in contact with a portion of the articulating member and a spinal rod abutment surface at a second end thereof that is within the spinal rod holder;
wherein expansion of the articulating member in response to receipt of a downward force exerted on the articulating member by the threaded nut moves the spinal rod abutment member into the spinal rod holder such that the spinal rod abutment surface abuts a spinal rod to fix the spinal rod to the spinal rod holder and fixes rotational orientation of the spinal rod holder.
12. The spinal rod connector assembly of claim 11 , further comprising:
a retaining ring situated about the spinal rod holder adjacent the body, the retaining ring configured to aid in fixing the rotational orientation of the spinal rod holder in response to receipt of the downward force exerted on the articulating member by the threaded nut.
13. The spinal rod connector assembly of claim 12 , wherein:
the spinal rod holder includes a first set of teeth situated on an annular end of the spinal rod holder that is received against a ledge of the lateral bore; and
the retaining ring includes a second set of teeth situated on an annular periphery of the retaining ring adjacent the first set of teeth;
wherein the first and second set of teeth mesh in response to receipt of the downward force exerted on the articulating member by the threaded nut to thereby fix the rotational orientation of the spinal rod holder.
14. The spinal rod connector assembly of claim 11 , wherein the articulating member includes an upper lip that abuts the spinal rod component in response to receipt of the downward force exerted on the articulating member.
15. The spinal rod connector assembly of claim 14 , wherein the upper lip has a thickness that applies an increase in lateral force against the spinal rod component relative to the downward force exerted on the articulating member.
16. The spinal rod connector assembly of claim 11 , wherein the articulating member has a clasping area at a lower end thereof that is configured to clamp onto the head of the vertebral bone screw.
17. The spinal rod connector assembly of claim 11 , wherein the articulating member has a chamfer on an upper end thereof that is configured to interface with a chamfer of the threaded nut.
18. The spinal rod connector assembly of claim 11 , wherein;
the lower bore of the body is tapered; and
a lower end of the articulating member is tapered complementarily to the tapered lower bore of the body.
19. The spinal rod connector assembly of claim 11 , wherein the body defines a second pivot bore in communication with the internal cavity, wherein the second pivot bore is axially aligned with the first pivot bore, and wherein the spinal rod connector assembly further includes a second pivot pin received by the second pivot bore and the second hemispherical cutout.
20. The spinal rod connector assembly of claim 19 , wherein the articulating member pivots about an axis defined by the first and second pivot pins.