Extramedullary Bone Lengthening Device with Dynamic Axial Stabilization

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Solution Overview

Problem

Current bone lengthening and stabilization devices face challenges such as rigid fixation leading to anatomical reduction requirements, intolerance due to pain and infection from external stabilization systems, and difficulties with intramedullary systems like avascular necrosis and varus deformity.

Innovation Solution

An internal extramedullary locked plate-like bone stabilization and lengthening device with dynamic axial stability, utilizing a canulated double-locking assembly for fixation with tension-locked Kirschner wires or cerclage wires, allowing for relative stability and hybrid fixation mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If locked osteosynthesis plates are used for bone fixation, then bone fixation stability is improved, but anatomical reduction is required and the system becomes too rigid

Engineering Contradiction:

Improvebone fixation stabilityVSAvoidanatomical reduction requirement

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by transforming the rigid locked plate system into a dynamic system through the addition of a telescopic element with sliding mechanism. This allows the plate to adapt its length and configuration, enabling use in both anatomical and non-anatomical reduction scenarios while maintaining fixation stability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the physical parameters of the fixation system by introducing a telescopic mechanism that allows variable length adjustment. This parameter change enables the system to accommodate different bone lengths and reduction states, transitioning from a fixed rigid structure to an adjustable dynamic structure.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If external stabilization systems with Schanz nails are used, then bone stabilization is achieved, but intolerance due to pain and infection occurs

Engineering Contradiction:

Improvebone stabilizationVSAvoidpain and infection

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the stabilization function from external systems and relocates it to an internal extramedullary locked plate system. By removing the need for external Schanz nails that penetrate soft tissues, the solution eliminates the associated pain and infection risks while maintaining bone stabilization capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an internal extramedullary locked plate as an intermediary structure that provides bone stabilization without requiring external penetration. This intermediary device acts as a mediator between the bone and external environment, eliminating the need for skin-penetrating fixation elements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Length of moving object

If intramedullary lengthening nails are used, then internal bone lengthening is achieved, but avascular necrosis and varus deformity occur

Engineering Contradiction:

Improvebone lengthVSAvoidavascular necrosis and varus deformity

Core Design Contradiction:

Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the lengthening function from intramedullary nails and relocates it to an extramedullary position. By placing the lengthening mechanism outside the medullary canal but still internally, the system achieves bone lengthening without the harmful effects of intramedullary placement such as avascular necrosis and varus deformity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions the lengthening mechanism from an intramedullary (inside the bone canal) position to an extramedullary (outside the bone canal) position. This spatial repositioning in another dimension allows the lengthening function to be performed without compromising blood supply or causing deformity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Stability of the object's composition

If locked plate systems are used, then rigid fixation is achieved, but dynamic axial stability is lost

Engineering Contradiction:

Improvefixation rigidityVSAvoiddynamic axial stability

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of moving object

Solution Approach 1:

The patent applies dynamics by integrating a telescopic element with sliding mechanism into the locked plate system. This dynamic component allows controlled movement and length adjustment while maintaining overall fixation stability, providing both rigidity and dynamic axial stability simultaneously.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12303175B2Extramedullary internal bone lengthening and fixation device with dynamic axial stabilization

Publication Date: 2025.05.20 RUSSI MARTIN

AI summary

An internal extramedullary bone lengthening device with dynamic axial stabilization includes two plate-like bone fixation elements shaped as a locked plate with bone fixation in a proximal sector and a distal sectors, wherein the bone fixation elements comprises a double-locking canulated assembly configured to allow bone fixation with tension Kirschner wires and/or tension cerclage wires; an intermediate sliding zone with a tubular or semi-tubular shape, the intermediate sliding zone configured to support the Kirschner wires and/or the tension cerclage wires; and a motor configured to actuate the intermediate sliding zone.