Active Bone Compression Screw With SMA Tension Adjustment

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Solution Overview

Problem

Current active compression screws for bone fusion are limited in their ability to adjust compression over time, have complex constructions, and cannot be scaled down for small bones, leading to complications in surgical procedures and increased costs.

Innovation Solution

Development of a unitary contiguous compression apparatus with adjustable axial tension capabilities, allowing for active compression of bone segments through mechanisms like Shape Memory Alloy (SMA) and perforations, enabling flexible deployment and scalable force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If standard compression screws are used, then bone fragments are held in place, but the device cannot maintain compressive load dynamically as bone remodels

Engineering Contradiction:

Improveduration of compressive forceVSAvoidability to maintain compression dynamically

Core Design Contradiction:

Duration of action of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static compression screw into a dynamic device by incorporating a shape memory alloy (SMA) element that can actively adjust its length in response to temperature changes or other stimuli. This allows the compression force to be maintained dynamically throughout the bone healing and remodeling process, rather than being fixed at implantation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the physical state or properties of the compression mechanism by using shape memory alloy material that can alter its dimensional parameters (length, shape) in response to external conditions such as temperature. This enables the device to adapt its compression force over time as bone density and geometry change during healing.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If active compression screw concepts are used, then axial tension capability is provided, but the construction becomes complicated and manufacturing becomes expensive

Engineering Contradiction:

Improveaxial tension capabilityVSAvoidconstruction complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single integrated component: the compression screw body, the shape memory alloy element, and the activation mechanism are merged into one unitary structure. This eliminates the need for separate components and complex assembly, thereby reducing manufacturing complexity while maintaining axial tension capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The shape memory alloy element serves multiple functions simultaneously: it provides the compression force, acts as the structural element of the screw, and serves as the actuator when stimulated. This multi-functionality reduces the overall device complexity compared to systems that require separate components for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Force

If current active compression screws are used, then some axial tension capability is provided, but the ability to adjust compression over time is limited

Engineering Contradiction:

Improveaxial tension forceVSAvoidadjustability of compression

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The invention enables dynamic adjustment of compression force through the shape memory alloy's ability to change length when stimulated (e.g., by temperature change, electrical current, or magnetic field). This allows the compression force to be adjusted non-invasively or minimally invasively over time, improving ease of operation compared to fixed or statically adjustable screws.

Inventive Principle:

Principle #15Dynamics

4Reliability

If standard compression devices are used, then bone fragments are stabilized, but the devices cannot be scaled down for small bones

Engineering Contradiction:

Improvestabilization capabilityVSAvoidscalability to small bones

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The shape memory alloy element can be manufactured in various sizes and geometries, allowing the same fundamental design to be scaled down for small bones such as fingers or toes while maintaining the essential compression and stabilization functions. The material's properties remain consistent across different scales.

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 apparatus provides continuous axial tension for extended bone fusion periods, accommodating varying bone absorption and anatomic features, promoting stronger healing with adjustable force delivery and flexibility in surgical procedures.

Implementation Method 1

Mechanisms like Shape Memory Alloy (SMA) and perforations, enabling flexible deployment and scalable force application

Methodology Applied

Scientific EffectShape Memory Alloy: Shape Memory Alloy

Implementation Method 2

The Shape Memory Alloy (SMA) and perforations, enabling flexible deployment and scalable force application

Methodology Applied

Scientific EffectPhase transformation: Phase Change

Implementation Method 3

perforations, enabling flexible deployment and scalable force application

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS20260013920A1Active compression apparatus, methods of assembly and methods of use

Publication Date: 2026.01.15 CONVENTUS ORTHOPAEDICS INC

AI summary

Compression devices for joining tissue and methods for using and fabricating the same.