Modular bone screw

Patent metadata

Field	Value
Publication number	US-11350968-B2
Application number	US-202016790098-A
Country	US
Kind code	B2
Filing date	Feb 13, 2020
Priority date	Apr 10, 2017
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A modular polyaxial bone screw includes a poly-axial bone screw, a polyaxial tulip head, and a collet disposed within the tulip head, the collet interacting with the bone screw and tulip head providing an interference fit with the bone screw head to lock orientation of the tulip head on and relative to the bone screw. Inner configurations of the tulip head interact with outer configurations of the collet to lock axial and/or rotational position of the collet within and relative to the tulip head, and thus about the bone screw head. The collet also has a resilient, tapered base with a plurality of slots in and about its end that allow the end to splay outwardly over and upon the head of the bone screw to create a snap or frictional interference fit between the splayed collet and the bone screw head when a spine rod is fixed in the tulip head.

First claim

What is claimed is:

1. A modular bone screw assembly for holding a spine rod in a fixed spatial orientation relative to vertebral bone, the modular bone screw assembly comprising:
a bone screw having a threaded shank and a screw head;
a rod holder disposed on the screw head and configured to move relative to the screw head before the rod holder is fixed in spatial orientation relative to the bone screw, and configured to receive and hold a spine rod as the spatial orientation of the rod holder is fixed, the rod holder having a bore extending from a first end of the rod holder to a second end of the rod holder and having an upper portion, inner threading for threaded receipt of a set screw, and a lower portion sized to receive the head of the bone screw in its entirety; and
a collet disposed in the interior of the rod holder, the collet having a lower section of a first diameter with a first end resting about the screw head and configured to splay on the screw head and fix a spatial orientation of the rod holder relative to the bone screw through interference between the first end, the screw head, and the rod holder when a spine rod is received in and affixed to the rod holder by the set screw, and an upper section of a second diameter that is smaller than the first diameter of the lower section;
wherein one of the rod holder and the collet includes a lip extending therefrom, and the other of the rod holder and collet includes a ledge that captures the lip to retain the collet in its axial position.

2. The bone screw assembly of claim 1 , wherein the lip extends radially inward from an inner wall of the rod holder.

3. The bone screw assembly of claim 2 , wherein the ledge extends about an outer wall of the collet.

4. A modular bone screw comprising:
a bone screw having a threaded shank and a screw head;
a rod holder disposed on the screw head and configured to move relative to the screw head before the rod holder is fixed in spatial orientation relative to the bone screw, and to receive and hold a spine rod in spine rod notches disposed in a first end of the rod holder once the spatial orientation of the rod holder is fixed, the rod holder having a bore extending from the first end to a second end of the rod holder having an upper portion, inner threading on the upper portion for threaded receipt of a set screw, and a lower portion sized to receive the screw head of the bone screw, and an inner configuration on the lower portion, the inner configuration consisting of a plurality of projections each one of which extends radially inward from an inner circumference of the lower inner generally cylindrical wall; and
a collet disposed in the interior of the rod holder, the collet having a tapered first end resting about the screw head and having a plurality of cutouts configured to allow the tapered first end of the collet to splay about the screw head and fix a spatial orientation of the rod holder relative to the bone screw through interference between the tapered first end, the screw head, and the rod holder when a spinal rod is received in and affixed to the rod holder by the set screw, the collet having a second end axially above the tapered first end and an outer configuration on an outer wall between the tapered first end and the second end that cooperates with the inner configuration of the rod holder to fix axial and rotational position of the collet relative to the rod holder, the outer configuration consisting of a plurality of depressions on a circumference of the outer wall whereby reception of the plurality of projections of the rod holder in the plurality of depressions of the collet retains the collet in its axial position;
wherein one of the rod holder and the collet includes a plurality of protuberances extending therefrom, and the other of the rod holder and collet includes a plurality of depressions that receives the plurality of protuberances to retain the collet in its position.

5. The modular bone screw of claim 4 , wherein the plurality of protuberances extend radially inward from an inner wall of the rod holder.

6. The modular bone screw of claim 5 , wherein the plurality of depressions are spaced apart an outer wall of the collet.

7. The modular bone screw of claim 4 , wherein the plurality of protuberances comprise four radially inward projections.

8. The modular bone screw of claim 7 , wherein the four radially inward projections are disposed equally about the inner circumference of the inner wall.

9. The modular bone screw of claim 8 , wherein the plurality of depressions comprise four depressions.

10. The modular bone screw of claim 9 , wherein the four depressions are disposed equally about the circumference of the outer wall.

Assignees

• Life Spine Inc

Inventors

• Samuel Forrest
• Palagi Gregory

Classifications

• A61B17/7037 Primary

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

• A61B17/7032 Primary

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

• A61B17/863

  with thread interrupted or changing its form along shank, other than constant taper · CPC title

• A61B2090/037

  with a frangible part, e.g. by reduced diameter · CPC title

• A61B17/8605

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