Implant assembly with a rigid interface

Patent metadata

Field	Value
Publication number	US-9622788-B2
Application number	US-201113287468-A
Country	US
Kind code	B2
Filing date	Nov 2, 2011
Priority date	Nov 2, 2011
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

An implant assembly and a method of assembling the same are provided, the implant assembly including a receiver extending along a central longitudinal axis between a proximal end and an opposite distal end, the receiver including a distal portion defining a receptacle opening at the distal end and a pair of arms extending from the distal portion along the central longitudinal axis on opposite sides of a passage with the passage opening at opposite sides of the receiver, a bone anchor including a distal bone engaging portion and a head at a proximal end of the distal bone engaging portion, the head being positioned in the receptacle with the bone engaging portion in a selected orientation relative to the central longitudinal axis of the receiver and a connector member configured to form a rigid interface between the receiver and the head of the bone anchor thereby providing torque transfer throughout the implant assembly.

First claim

What is claimed is:

1. An implant assembly comprising:
a receiver extending along a longitudinal axis between a proximal end and a distal end, the proximal end configured for receiving an elongated member, the distal end comprising a threaded inner surface defining a cylindrical shaped opening that receives a correspondingly shaped threaded head of a bone anchor such that the threads on the inner surface engage the threads on the head, the bone anchor having a tip opposite the head, the tip configured to engage bone, a connector member that contacts at least the distal end of the receiver and at least the head of the bone anchor to provide a rigid interface between the receiver and the head of the bone anchor such that the receiver is fixed relative to the bone anchor, the assembly further comprising a saddle, separate from the connector member, inserted into the receiver such that the saddle can pivot therein.

2. An implant assembly of claim 1 , wherein:
the receiver comprises a first aperture extending perpendicular to the longitudinal axis;
the head comprises a second aperture extending perpendicular to the longitudinal axis, the first and second apertures being coaxial when the threads on the inner surface engage the threads on the head; and
the connector member comprises a cross pin that extends through the first aperture and the second aperture to form the rigid interface.

3. An implant assembly of claim 1 , wherein the rigid interface is formed by fusing the connector member to the head of the bone anchor.

4. An implant assembly according to claim 3 , wherein the fusing is induced by laser welding, TIG welding or MIG welding.

5. An implant assembly of claim 1 , wherein the connector member is a washer that has a keyed outer surface that engages the receiver such that relative rotation between the washer and the receiver is resisted.

6. An implant assembly of claim 1 , wherein the bone anchor includes an annular flange positioned between the head and the tip that engages a distal end surface of the receiver when the threads on the inner surface engage the threads on the head to prevent the receiver from translating distally relative to the bone anchor along the longitudinal axis.

7. An implant assembly of claim 1 , wherein the implant assembly provides a mono-axial type of assembly.

8. An implant assembly of claim 1 , wherein:
the connector member is a washer;
the bone anchor includes an annular flange positioned between the head and the tip and the receiver comprises a cutout that is distal to the cylindrical shaped opening; and
the washer is positioned within the cutout such that a distal surface of the washer engages the annular flange.

9. An implant assembly of claim 1 , wherein:
the connector member is a washer; and
the washer is not supported by the receiver.

10. An implant assembly of claim 1 , wherein the saddle is spaced apart from the connector member.

11. An implant assembly of claim 1 , wherein an outer surface of the saddle engages an inner surface of the receiver to space the saddle apart from the head.

12. An implant assembly comprising:
a monolithic receiver extending along a central longitudinal axis between a proximal end and an opposite distal end, the receiver including a distal portion comprising a threaded inner surface defining a cylindrical shaped receptacle opening at the distal end and a pair of arms extending from the distal portion along the central longitudinal axis on opposite sides of a passage with the passage opening at opposite sides of the receiver, the receiver including a bottom surface extending along the passage between the pair of arms, wherein the receptacle opens into the passage through the bottom surface;
a bone anchor including a distal bone engaging portion and a threaded cylindrical shaped head at a proximal end of the bone engaging portion, the head being positioned in the receptacle such that the threads on the inner surface engage the threads on the head;
a connector member configured to form a rigid interface between the receiver and the head of the bone anchor such that the receiver is fixed relative to the bone anchor; and
a saddle, separate from the connector member, positioned in the passage of the receiver adjacent to a bottom surface of the receiver, the saddle including a proximal support surface and a distal surface opposite the proximal support surface.

13. An implant assembly of claim 12 , wherein the connector member is a washer or a cross pin.

14. An implant assembly of claim 12 , wherein the rigid interface is formed by fusing the connector member to the head of the bone anchor.

15. An implant assembly of claim 12 , wherein the rigid interface is formed by subjecting the connector member to laser welding, TIG welding or MIG welding to the head of the bone anchor.

16. An implant assembly of claim 12 , wherein the head of the bone anchor further defines at least one detent in a threaded portion thereof that extends perpendicular to the central longitudinal axis, the opposite distal end of the receiver further defines at least one aperture adjacent a distal side portion of the receiver that extends perpendicular to the central longitudinal axis, the aperture configured for alignment with the detent of the head of the bone anchor, and at least a cross pin extending through the at least one aperture of the receiver into the at least one detent of the bone anchor thereby forming a rigid interface between the receiver and the bone anchor.

17. An implant assembly of claim 12 , wherein the head of the bone anchor further defines at least one detent in a threaded portion thereof, the opposite distal end of the receiver further defines at least one aperture adjacent a distal side portion of the receiver, the aperture configured for alignment with the detent of the head of the bone anchor, and a medical grade threadlocker adhesive, the threadlocker adhesive insertable into the aperture of the receiver, thereby forming a rigid interface between the receiver and the bone anchor.

18. An implant assembly of claim 12 , wherein the receiver and the bone anchor are manufactured from different materials from one another and the connector member and the bone anchor are manufactured of the same material selected from the group consisting of titanium alloy, cobalt-chrome-molybdenum alloy and other biologically compatible composite materials.

19. An implant assembly of claim 12 , further comprising an engaging member engaged to the pair of arms to secure a connecting element against the proximal support surface of the saddle, wherein the saddle engages the receiver and is limited to movement in the receiver about the central longitudinal axis of the receiver.

20. An implant assembly of claim 12 , further comprising a marker disposed on the implant assembly for indicating a position of the implant assembly.

Assignees

• Rezach William Alan
• Taylor Harold S
• Taylor Andrew
• Warsaw Orthopedic Inc

Inventors

• Rezach William Alan
• Taylor Harold S
• Taylor Andrew

Classifications

• A61B17/70

  Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant · CPC title

• A61B17/7032

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

• A61B17/7038

  to a different extent in different directions, e.g. within one plane only · CPC title

• A61B17/7037 Primary

  wherein pivoting is blocked when the rod is clamped · CPC title