Polyaxial bone screw with shank articulation pressure insert and method

Patent metadata

Field	Value
Publication number	US-9456853-B2
Application number	US-80266810-A
Country	US
Kind code	B2
Filing date	Jun 11, 2010
Priority date	May 27, 2005
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A polyaxial bone screw assembly includes a threaded shank body having an upper portion, a receiver member or head, a retaining and articulating structure, and a pressure insert disposed between the shank upper portion and a rod. The receiver has a U-shaped cradle defining a channel for receiving a spinal fixation rod and a receiver cavity. The retaining and articulating structure attaches to the shank and rotates with the shank in the cavity during positioning. The pressure insert presses upon the shank upper portion and not the retaining and articulating structure.

First claim

What is claimed and desired to be secured by Letters Patent is as follows:

1. A bone anchor assembly comprising:
a receiver, the receiver having a top side surface, a front side surface and a back side surface and includes a first pair of upwardly extending arms forming a channel therebetween and mateable with a closure to securely lock a bone anchor with respect to a rod positionable within the channel of the receiver, wherein:
each upwardly extending arm having an outward facing horizontal elongated radiused groove about a circumference of the receiver extending to at least one of the front side surface and the back side surface and located a distance from the top side surface, wherein the distance remains constant along a horizontal length of the groove, the grooves of each upwardly extending arm opposed in parallel relation to each other, and wherein the closure is positioned inwardly in the receiver with respect to the grooves and only engages the rod and the receiver.

2. The bone anchor assembly of claim 1 , wherein the grooves are symmetrically positioned on the receiver.

3. A pivotal bone anchor assembly comprising:
a) a shank having an elongate body for fixation to a bone, and a central bore along an entire length thereof;
b) a receiver pivotally attached to the shank and having a top side surface, a front side surface, a back side surface, and first and second arms defining a channel, each of the first and second arms having an outer, elongated, horizontally extending groove radiused about a circumference of the receiver and located a distance from the top side surface, wherein the distance remains constant along a horizontal length of the groove, and extending to at least one of the front side surface and the back side surface; and
c) a closure for closing the channel, the closure engaging only the receiver and a rod within the channel on a top surface thereof, and wherein the closure is positioned inwardly in the receiver with respect to each groove, so as to remain spaced from the grooves.

4. The assembly of claim 3 , further comprising a separate retainer that is sized and shaped to be positioned into the receiver and that engages the shank having an Upper capture portion, wherein the shank can polyaxially pivot relative to the receiver during positioning of the shank with respect to the receiver.

5. A bone anchor assembly adapted to be attached to a vertebra of a patient, comprising: a receiver, the receiver mateable with a closure to securely lock a bone anchor, wherein
a) the receiver includes a top side surface, a front side surface, a back side surface and a first pair of upwardly extending arms forming a rod receiving channel therebetween, at least one arm having an outward facing, horizontal elongated groove radiused about a circumference of the receiver extending to at least one of the front side surface and the back side surface and located a distance from the top side surface, wherein the distance remains constant along a horizontal length of the groove, and wherein the closure when mated to the receiver remains spaced from the elongate, horizontal groove and engages only the receiver and a rod.

6. A bone anchor comprising a receiver, the receiver mateable with a closure to securely lock the bone anchor, wherein:
(a) the receiver includes a top side surface, a front side surface, a back side surface and a first pair of upwardly extending arms forming a channel therebetween, at least one arm having an outward facing, horizontal elongated groove radiused about a circumference of the receiver extending to at least one of the front side surface and the back side surface and located located a distance from the top side surface, wherein the distance remains constant along a horizontal length of the groove, and wherein the closure is mateable with the receiver and the outward facing, elongate, horizontal groove remains spaced from the closure and wherein the closure only engages the receiver and a rod.

Assignees

• Jackson Roger P

Inventors

• Jackson Roger P

Classifications

• A61B17/704 Primary

  the longitudinal element passing through a ball-joint in the screw head · CPC title

• A61B17/7001

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

• A61B17/7032

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

• A61B17/7037 Primary

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

• A61B17/7082

  for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws · CPC title