Tandem rod connectors and related methods

Patent metadata

Field	Value
Publication number	US-10869695-B2
Application number	US-201916280918-A
Country	US
Kind code	B2
Filing date	Feb 20, 2019
Priority date	Feb 10, 2017
Publication date	Dec 22, 2020
Grant date	Dec 22, 2020

Abstract

Connectors are disclosed herein that can be used to attach a rod to a bone anchor assembly that is already occupied by a separate rod. Various ways of attaching the connector to the bone anchor assembly are disclosed, including arrangements in which the connector is locked to the bone anchor, arrangements in which the connector is constrained in one or more degrees of freedom relative to the bone anchor, arrangements in which the connector is adjustable in one or more degrees of freedom relative to the bone anchor, and arrangements that include a spherical articulation joint. In some embodiments, attachment of the connector to a bone anchor can be aided with the use of a positioner. The geometry of the connector can be selected to minimize the offset between a first rod received in the bone anchor assembly and a second rod received in the connector, for example using an angled or curved rod recess and/or a fastener, or set screw, that is offset from the center of the rod or angled relative to the bone anchor. The connector can be configured to align the first and second rods in a common coronal plane, or can be configured to position one rod more anterior or posterior than the other rod.

First claim

The invention claimed is:

1. A connector assembly, comprising:
a connector having a proximal end and a distal end that define a proximal-distal axis, the connector including:
a coupling portion having an opening configured to mate the connector to a receiver member of a bone anchor assembly, the bone anchor assembly having a first rod-receiving recess for receiving a first rod, and
a receiving portion in which a second rod-receiving recess is formed, the second rod-receiving recess being configured to receive a second rod;
a first fastener having a distal end configured to engage the receiver member to lock the first rod to the receiver member and a proximal end configured to engage the coupling portion; and
a locking nut mateable to the first fastener to secure the connector to the receiver member, the locking nut being configured to be received within the opening of the coupling portion,
wherein the opening of the coupling portion includes an inner articulation surface that interfaces with an outer articulation surface formed in the locking nut, and
wherein the inner articulation surface is complementary to the outer articulation surface such that the locking nut is polyaxially movable within the opening relative to the connector.

2. The assembly of claim 1 , wherein the inner articulation surface of the coupling portion is spherical.

3. The assembly of claim 1 , wherein the inner articulation surface and the outer articulation surface have substantially the same radius of curvature.

4. The assembly of claim 1 , wherein the locking nut expands or contracts in a radial direction.

5. The assembly of claim 4 , wherein the locking nut further comprises one or more slits formed therein that allows for expansion or contraction in the radial direction.

6. The assembly of claim 5 , wherein the one or more slits extend from the proximal end to the distal end of the locking nut.

7. The assembly of claim 6 , wherein the first slits are formed in a proximal surface of the locking nut and the second, diametrically opposed slits are formed in the distal surface of the locking nut.

8. The assembly of claim 6 , wherein the first slits are angularly offset relative to the second slits about a circumference of the locking nut.

9. The assembly of claim 8 , wherein the offset is approximately 90 degrees.

10. The assembly of claim 5 , wherein the one or more slits further comprise first and second slits that are diametrically opposed.

11. The assembly of claim 1 , further comprising a driver instrument for rotating the locking nut about the first fastener to thread the locking nut onto the first fastener.

12. The assembly of claim 11 , wherein the threads of the threaded throughhole and the threads of the first fastener cooperate to cause radial expansion of the locking nut as the locking nut rotates in a first direction relative to the first fastener and radial contraction of the locking nut as the locking nut rotates in a second, opposite direction relative to the first fastener.

13. The assembly of claim 1 , wherein the locking nut includes a threaded throughhole.

14. The assembly of claim 13 , wherein threads of the threaded throughhole are conical or tapered.

15. The assembly of claim 1 , wherein the assembly includes a first, unlocked configuration in which the locking nut is radially-contracted to allow polyaxial movement of the connector relative to the locking nut and a second, locked configuration in which the locking nut is radially-expanded to lock polyaxial movement of the connector relative to the locking nut.

16. The assembly of claim 15 , wherein polyaxial movement of the connector relative to the locking nut is locked by being compression fit against the inner surface of the first portion.

17. The assembly of claim 15 , wherein a maximum outer diameter of the locking nut in the unlocked configuration permits the connector to polyaxially rotate about the locking nut.

18. The assembly of claim 1 , wherein the locking nut is formed from a mesh material.

19. The assembly of claim 1 , wherein the assembly allows for a range of articulation between the connector and the receiver member such that the locking nut is partially tightened onto the first fastener.

20. The assembly of claim 1 , further comprising a first planar region and a second planar region on the distal surface of the connector, the second planar region extending obliquely from the first planar region.

21. The assembly of claim 20 , wherein the first planar region is configured to abut the receiver member to allow pivoting in a first direction and preventing pivoting in a second direction.

22. The assembly of claim 21 , wherein the first direction is in a direction parallel to the first rod and the second direction is a direction perpendicular to the first rod.

23. The assembly of claim 1 , wherein the first fastener extends through the opening formed in the coupling portion.

24. A connector assembly, comprising:
a connector having a proximal end and a distal end that define a proximal-distal axis, the connector including:
a coupling portion having an opening configured to mate the connector to a receiver member of a bone anchor assembly, the bone anchor assembly having a first rod-receiving recess for receiving a first rod, and
a receiving portion in which a second rod-receiving recess is formed, the second rod-receiving recess being configured to receive a second rod;
a first fastener having a distal end configured to engage the receiver member to lock the first rod to the receiver member and a proximal end configured to engage the coupling portion; and
a locking nut mateable to the first fastener to secure the connector to the receiver member, the locking nut being configured to be received within the opening of the coupling portion,
wherein the opening of the coupling portion includes an inner articulation surface that interfaces with an outer articulation surface formed in the locking nut, and
wherein the locking nut expands or contracts in a radial direction.

Assignees

• Medos Int Sarl

Inventors

• Carruth Robert
• Dieselman John
• Lee Kevin
• Hawkins J Riley

Classifications

• A61B17/7049 Primary

  Connectors, not bearing on the vertebrae, for linking longitudinal elements together (A61B17/7055, A61B17/7053, A61B17/7019 take precedence) · CPC title

• A61B17/7032

  Screws or hooks with U-shaped head or back through which longitudinal rods pass · CPC title

• A61B17/8605

  Heads, i.e. proximal ends projecting from bone · CPC title

• A61B17/7001

  Screws or hooks combined with longitudinal elements which do not contact vertebrae (A61B17/7058 takes precedence) · CPC title

• A61B17/8685

  comprising multiple separate parts · CPC title