Rod coupling systems and devices and methods of making and using the same
Provided are rod coupler devices, systems, kits and methods, which include at least one saddle having a concave configuration that either abuts a bone fastener and/or a locking cap and is shaped so as to contact the rod in two or more lines of contact, which reduces pressure on the rod, and therefore permits use of a rod having various materials, such as PEEK, without significant deformation of the rod. Also provided is the saddle itself and integrated locking caps that include a saddle, the locking cap and a set screw. Also provided are elongate rods having advantageous shapes, configurations, and/or compositions for rod coupler devices, systems and methods. Further provided are screw and cap devices and systems that themselves include a concave configuration so as to contact a rod in two or more lines of contact, which reduces pressure on the rod.
1. A rod coupler system comprising:
a coupling body having a bone fastener disposed therethrough, the coupling body having at least two sidewalls that define two upwardly extending arms that define two slots capable of receiving an elongate rod;
a locking cap;
a saddle having a first side configured to couple to the locking cap and a second side opposite said first side having a concave portion configured to abut the elongate rod along at least two lines of contact between said saddle and the elongate rod, the saddle having a first end and a second end, at least a portion of the first end of the saddle extending into one of the two slots and at least a portion of the second end of the saddle extending into the other of the two slots, wherein the first side of the saddle is configured to be selectively locked onto the locking cap prior to insertion of the locking cap and saddle into the coupling body such that the locking cap cannot be pulled away from the saddle; and
an elongate rod comprised of a non-metallic material.
2. The rod coupler system of claim 1 , wherein said concave portion of said saddle is shaped so as to substantially correspond to a portion of surface area of the elongate rod.
3. The rod coupler system of claim 1 , further comprising a set screw disposed in said locking cap.
4. The rod coupler system of claim 1 , wherein said bone fastener comprises a pedicle screw.
5. The rod coupler system of claim 1 , further comprising at least one additional component selected from the group consisting of a set screw, a rod, a tool for assembling the rod coupler system or portions thereof, a tool for inserting the rod coupler system into a patient, and a tool for tightening a set screw so as to secure a rod within the rod coupler system.
6. The rod coupler system of claim 1 , wherein the elongate rod is formed of PEEK.
7. The rod coupler system of claim 1 , wherein the elongate rod is a composite rod formed of at least two materials, one being PEEK.
8. A coupling system comprising:
a first saddle comprising:
a first side configured to be detachably attached to a locking cap for a coupling body, wherein the first side is configured to selectively lock the first saddle onto the locking cap prior to insertion of the locking cap and first saddle into the coupling body such that the locking cap cannot be pulled away from the first saddle; and
a second side opposite said first side of said saddle, said second side having a concave portion configured to abut a first end of an elongate rod along at least two lines of contact between said saddle and said elongate rod;
a second saddle comprising:
a first side configured to be engaged with a bone screw for a coupling body; and
a second side opposite said first side of said saddle, said second side having a concave portion configured to abut a second end of the elongate rod along at least two lines of contact between said saddle and said elongate rod.
9. The system of claim 8 , wherein at least one of the first or second saddle radius is configured to be a smaller radius than a radius of the elongate rod.
10. The system of claim 9 , wherein at least one of the first or second saddle further comprises at least one dimple within the radius, which is configured to also make contact with said elongate rod, such that said saddle is configured to abut said rod along at least three lines of contact.
11. The system of claim 8 , wherein the first saddle is rotated independently from the locking cap.
12. The system of claim 8 , wherein the first saddle is rotated when the locking cap is rotated.
13. A rod coupler system comprising:
a coupling body having a bone fastener disposed therethrough, the coupling body having at least two sidewalls that define two upwardly extending arms that define two slots capable of receiving an elongate rod;
a locking cap adapted for attachment to said coupling body, and
a saddle having a first side abutting said locking cap and a second side opposite said first side having a concave portion configured to abut an elongate rod along at least two lines of contact between said saddle and said elongate rod, the saddle having a first end and a second end, at least a portion of the first end of the saddle extending into one of the two slots and at least a portion of the send end of the saddle extending into the other of the two slots, wherein the saddle is configured to be selectively locked onto the locking cap prior to insertion into the coupling body such that the locking cap cannot be pulled away from the saddle; and
an elongate rod comprised of a non-metallic material.
14. The rod coupler system of claim 13 , wherein said concave portion of said saddle is shaped so as to correspond to a portion of surface area of the elongate rod.
15. The rod coupler system of claim 13 , further comprising at least one additional element selected from the group consisting of the rod and a set screw disposed in said locking cap.
16. The rod coupler system of claim 13 , wherein said bone fastener comprises a pedicle screw.
17. The rod coupler system of claim 13 , wherein the elongate rod is formed of PEEK.
18. The rod coupler system of claim 13 , wherein the elongate rod comprises a titanium rod pressed into a PEEK tube.