Overmolded Bone Screw Structure for Clearer X-Ray Imaging

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Solution Overview

Problem

Conventional bone screws and pedicle screws made of metallic materials are highly visible on X-ray, obstructing the visibility of patient anatomy and hindering effective imaging.

Innovation Solution

A bone screw design comprising a metallic first portion and a non-metallic overmold, such as PEEK, mechanically coupled through an overmold manufacturing process, reducing the overall metallic mass and enhancing X-ray visibility by minimizing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional metallic materials are used for bone screws, then strength and reliability are improved, but X-ray visibility of patient anatomy is hindered

Engineering Contradiction:
Improvebone screw strengthVSAvoidX-ray interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bone screw combines metallic material (for strength and reliability) with radiolucent material (for reduced X-ray interference), creating a composite structure that simultaneously addresses both requirements. The metallic portion provides mechanical strength while the radiolucent portion allows clear X-ray imaging of patient anatomy.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The bone screw is divided into distinct portions: a metallic portion (providing strength) and a radiolucent portion (reducing X-ray interference). This segmentation allows each portion to fulfill its specific function without compromising the other, resolving the contradiction between strength and imaging visibility.

Inventive Principle:
Principle #1Segmentation

2Strength

If metallic materials are used for bone screws, then mechanical strength is improved, but visibility of certain elements of patient anatomy is blocked

Engineering Contradiction:
Improvebone screw strengthVSAvoidanatomy visibility
Core Design Contradiction:
StrengthVSLoss of information

Solution Approach 1:

The invention uses a composite structure where metallic material provides the necessary mechanical strength while radiolucent material allows X-ray penetration, preventing information loss about patient anatomy during imaging procedures.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different portions of the bone screw have different material properties: the metallic portion is located where high strength is needed, while the radiolucent portion is positioned to minimize X-ray interference with anatomical imaging, allowing each region to optimize its local function.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4426215B1Bone screw having an overmold of a shank
Publication Date: 2025.12.24 WARSAW ORTHOPEDIC INC
  • EP4426215B1 patent drawingFigure 1
  • EP4426215B1 patent drawingFigure 2
  • EP4426215B1 patent drawingFigure 3

AI summary

A bone screw (100) that includes a first portion (30) extending from a first end to a second end in a longitudinal direction. The first portion has a head (31) that defines the first end and a shank (39) that defines the second end. Additionally, the first portion includes a metallic material and/or is formed of a metallic material, for example Titanium. A second portion (10) is mechanically coupled to the first portion and surround the shank, for example the second portion is screwed to the first portion or the second portion is directly formed to the first portion by an overmold process. The second portion has an exposed thread pattern and an exposed leading tip. Additionally, the second portion includes a thermoplastic material and/or is formed of a thermoplastic material such as PEEK.