Vertebral Implant Self-Locking Screw Mechanism

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Solution Overview

Problem

Conventional vertebral implants for spinal osteosynthesis face challenges in maintaining stable positioning within the intersomatic space without increasing surgical invasiveness, and existing stabilization methods can complicate removal, leading to potential implant migration and the need for invasive revisions.

Innovation Solution

A vertebral implant with an autonomous locking system comprising a screw and well design, featuring flexible male and female components that stress progressively during screw insertion, allowing for secure locking and easy unlocking, ensuring stable positioning without preventing removal, utilizing a retractable system to modify the screw head's circumference for flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional posterior pedicle instrumentation with orthopedic plates is used to stabilize the interbody cage, then the position of the cage is stabilized, but the vertebral wall thickness increases and the surgical procedure becomes more invasive

Engineering Contradiction:

Improvecage position stabilityVSAvoidsurgical invasiveness

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is nested within the screw structure itself, with the head comprising a locking element that interfaces with the well. This eliminates the need for external plates and separate stabilization devices, achieving cage stabilization through a self-contained screw-cage assembly that reduces surgical invasiveness while maintaining reliability

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The stabilization and locking functions are merged into the screw assembly. The screw head integrates the locking mechanism that directly engages with the cage well, combining fixation and stabilization into a single integrated component rather than requiring separate plates and screws

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If traditional stabilization devices are used to maintain cage position, then the cage remains stable, but implant removal becomes complicated and invasive

Engineering Contradiction:

Improvecage position stabilityVSAvoidimplant removal ease

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The locking mechanism employs dynamic elements including elastic deformation of the well walls and a retractable system in the screw head that modifies the head's circumference. These dynamic characteristics allow the mechanism to lock securely during implantation while enabling easy unlocking and removal by reversing the deformation through simple unscrewing motion

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The locking mechanism is self-actuating through the screwing motion itself. The progressive stress applied during screw insertion automatically triggers the locking action without requiring separate locking steps or tools, and the same unscrewing motion automatically triggers unlocking, eliminating the need for complex removal procedures

Inventive Principle:

Principle #25Self-service

3Reliability

If the screw head circumference is made rigid for stable locking, then the locking position is secure, but flexibility during screwing is reduced

Engineering Contradiction:

Improvelocking position securityVSAvoidscrew flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The screw head incorporates a retractable system with flexible elements that can deform radially. These flexible components allow the head to expand or contract its circumference as needed during screwing, providing adaptability during insertion while maintaining secure locking when engaged with the well

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The screw head's geometric parameter (circumference) is made variable through the retractable system. The head can dynamically change its radial dimension from a compressed state during insertion to an expanded locked state during fixation, allowing the same component to satisfy both flexibility and security requirements at different stages

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides stable and secure implant positioning while allowing for minimally invasive placement and easy removal, reducing the risk of implant migration and the need for surgical revisions, thus enhancing osteosynthesis and patient safety.

Implementation Method 1

said male and female means being mounted with a relative flexibility allowing, during the screwing of the screw into the bone mass through the well, a progressive and mutual tightening of the male and female means

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2854714B1Vertebral implant provided with a self locking and unlocking means

Publication Date: 2020.10.21 SPINK UP INC

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AI summary

The invention relates to a vertebral implant (1) intended to be implanted in a patient's intersomatic space and comprising an intersomatic cage (2) and at least one fixing screw (10) intended to be screwed into the bony mass through a well (7) of said cage (2) to stabilize the position of said cage (2) within the intersomatic space, said implant (1) being characterized in that the well (7) and the screw (10) form a system for the self‑locking of the screw (10) in the well (7), said system comprising a male means secured to the screw (10) and a female means formed by the walls (72) of the well (7), the male means being locked in position by the female means.