Nonmetal Implant Screw Locking via Self-Tapping Metal Threads

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Solution Overview

Problem

Current nonmetal orthopedic implants face limitations due to lower mechanical strength, weak screw grasp on bones, and inadequate locking force, which hinders complete installation and stable fixation, and existing solutions are complex and costly, increasing surgical risks and patient burden.

Innovation Solution

A nonmetal implant screw locking structure combining metal screws with nonmetal implants, featuring self-tapping bone threads and sharp-pointed objects that form threaded channels for secure locking, using materials like PEEK and artificial bone powder, and microcapsules for self-repair, simplifying installation and enhancing fixation strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nonmetal implants are used to reduce stress shielding and promote bone growth, then biocompatibility and bone healing are improved, but mechanical strength and locking force are insufficient

Engineering Contradiction:
Improvebone healing and biocompatibilityVSAvoidmechanical strength and locking force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses composite materials by combining nonmetal implant materials (such as PEEK, ceramic, or polymer) with metal screw components. The implant body is made of nonmetal material to reduce stress shielding and promote bone growth, while metal screws with self-tapping threads provide the necessary mechanical strength and locking force. This composite approach allows each material to contribute its advantageous properties to the overall system.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by having different material properties in different parts of the implant system. The implant body uses nonmetal material with elastic modulus close to bone for stress distribution and bone healing, while the screw portions use metal material with high strength for secure fixation. The sharp threads or sharp-pointed objects at the tail of the screw provide localized cutting and tapping action to create threaded channels in the nonmetal implant.

Inventive Principle:
Principle #3Local quality

2Force

If expansion or circlips are used to lock nonmetal implants, then locking force is provided, but device complexity and surgical risk increase

Engineering Contradiction:
Improvelocking forceVSAvoidstructure complexity and surgical complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent extracts the locking function from separate components (expansion elements or circlips) and integrates it directly into the screw structure itself. The metal screw with self-tapping threads and sharp-pointed objects performs both the function of securing the bone and providing locking force within the nonmetal implant, eliminating the need for additional locking components and simplifying the overall device structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements self-service by designing the metal screw to automatically create threaded channels and provide locking force during the insertion process. The sharp threads or sharp-pointed objects at the tail of the screw automatically cut and tap the nonmetal implant material as the screw is inserted, creating self-locking threaded channels without requiring separate locking operations or additional components.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If metal screws with self-tapping function are used in nonmetal implants, then installation simplicity is improved, but screw design complexity increases

Engineering Contradiction:
Improveinstallation simplicityVSAvoidscrew structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated screw structure. The metal screw combines the functions of bone anchoring, implant securing, and self-locking within one component. The bone threads at the front of the screw engage with bone tissue, while the sharp threads or sharp-pointed objects at the tail create and lock into threaded channels in the nonmetal implant, eliminating the need for separate drilling, tapping, and locking steps.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3705070B1Nonmetal implant screw locking structure
Publication Date: 2023.07.12 SHANGHAI REACH MEDICAL INSTR
  • EP3705070B1 patent drawingFigure 1~2c
  • EP3705070B1 patent drawingFigure 2d~3b
  • EP3705070B1 patent drawingFigure 4a~4e

AI summary

The invention provides a nonmetal implant screw locking structure, which has the advantages of simple structure, novel design, simple production and processing, and convenient clinical operation. In addition, the structure of the invention can be used for orthopedic nonmetal implants such as the bone injury repair plate, spinal fusion cage, spinal fixation plate, posterior cervical single trapdoor plate, posterior cervical plate, lumbar anterior plate and lumbosacral plate, bringing good economic and social benefits gradually.