US 12,551,251 B2Granted

Fixation assemblies for medical implants

AssigneeDynamic Spine Technology, LLC

InventorsAvery Lanman, Sara M. Layton, Shawn H. Culbertson, Yi Ren Chen

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Abstract

Systems, devices and methods are provided for implanting medical devices into patients. The systems, devices and methods are particularly useful for orthopedic implants, such as spinal implants that facilitate fusion of bone segments. A fixation assembly for an implant comprises a screw having a head and a shaft, and a washer having at least one outer surface with one or more frictional elements for engaging a surface of the implant. The shaft includes one or more projections that cooperate with the washer to prevent the washer from sliding back down the screw, while allowing for easy application of the washer to ensure optimal placement and desired contact with the screw head. The washer and/or the screw head may also include interlocking cams that create a wedge effect that inhibits the screw from backing out or loosening from a hole in bone or other tissue.

Claims24

Dependent claims

A fixation assembly for an implant, the assembly comprising:

a screw having a head, a shaft with a threaded portion and a shank portion between the threaded portion and the head;
a washer having at least one outer surface with one or more frictional elements for engaging a surface of the implant;
wherein the shaft comprises one or more projections extending from the shank portion, wherein the projections and the shank define a cross-sectional area;
wherein the washer defines an upper surface facing the head of the screw, a lower surface opposite the upper surface and a central opening extending from the upper surface to the lower surface, wherein the central opening has a cross-sectional area less than the cross-sectional area of the projections and the shank at, or near, the upper surface of the washer;
and
wherein the central opening comprises a cutout region at, or near, the lower surface of the washer such that the central opening has a cross-sectional area greater than the cross-sectional area of the projections and the shank at, or near, the lower surface of the washer.

3 more elements

A medical implant comprising:

an implantable body having an upper surface, a lower surface and a through hole;
a screw having a head and a shaft with a threaded portion;
and
a washer having at least one outer surface with one or more frictional elements for engaging a surface of the implant;
wherein the shaft comprises one or more projections extending from a shank portion between the threaded portion and the head;
wherein the washer defines an upper surface facing the head of the screw, a lower surface opposite the upper surface and a central opening extending from the upper surface to the lower surface, wherein the central opening has a cross-sectional area less than the cross-sectional area of the projections and the shank at, or near, the upper surface of the washer;
and
wherein the central opening comprises a cutout region at, or near, the lower surface of the washer such that the central opening has a cross-sectional area greater than the cross-sectional area of the projections and the shank at, or near, the lower surface of the washer.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/990,337Filed 18 Nov 2022 · us provisional application
Priority: 22 Nov 2021
Published: US 2023/0157738 A125 May 2023
Granted: 17 Feb 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification22 codes

A61B 17/8057
Immobilised relative to screws by interlocking form of the heads and plate holes, e.g. conical or threaded: the interlocking form comprising a thread
A61B 17/808
Cortical plates , i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates:…
A61B 17/863
Shanks, i.e. parts contacting bone tissue: with thread interrupted or changing its form along shank, other than constant taper
A61B 17/8695
Pins or screws or threaded wires; nuts therefor: washers