Shape Memory Alloy Spinal Template for Reusable Orthopedic Fixation

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Solution Overview

Problem

Existing spinal and orthopaedic rod templates made of aluminum alloys are prone to breaking when repeatedly bent and sterilized, and they lack the ability to maintain a consistent shape for multiple uses.

Innovation Solution

A template made of nickel-titanium alloy that can change configurations between a bendable state at room temperature and a memorized shape above body temperature, allowing for easy shaping and reuse without the need for manual unbending, using shape memory properties to revert to a pre-defined form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If rod templates are made of aluminum alloy to permit bending in the operating room, then ease of operation is improved, but reliability deteriorates due to risk of breaking when bent and sterilized repeatedly

Engineering Contradiction:

Improvebending capabilityVSAvoidbreakage risk

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent changes the material parameter from aluminum alloy to shape memory alloy (Nitinol), which fundamentally alters the mechanical properties. The shape memory alloy maintains flexibility at operating room temperature while providing superior strength and resistance to breakage during repeated bending and sterilization cycles

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the phase transition properties of shape memory alloy between martensite (soft, deformable) and austenite (hard, strong) phases. At operating room temperature, the alloy is in martensite phase allowing easy bending, while during sterilization or at body temperature, it transitions to austenite phase providing high strength and breakage resistance

Inventive Principle:

Principle #36Phase transitions

2Productivity

If rod templates are bent back and sterilized for repeated use, then productivity is improved, but manufacturing precision deteriorates due to remaining curvature different from original shape

Engineering Contradiction:

ImprovereusabilityVSAvoidshape consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs the phase transition from martensite to austenite during sterilization to automatically restore the template to its original memorized shape. This eliminates remaining curvature and ensures consistent shape precision across multiple reuse cycles without manual intervention

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The shape memory alloy template performs self-restoration of its original shape through the phase transition mechanism during sterilization. This self-service capability eliminates the need for manual unbending and ensures consistent shape precision automatically

Inventive Principle:

Principle #25Self-service

3Ease of operation

If rod templates are made of low strength aluminum alloy to enable bending, then ease of operation is improved, but strength deteriorates making them prone to breaking

Engineering Contradiction:

Improvebending flexibilityVSAvoidresistance to breaking

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent changes the material parameter from aluminum alloy to shape memory alloy, which provides a unique combination of low-temperature flexibility and high-temperature strength. The material maintains bending flexibility at operating room temperature while providing superior strength resistance during sterilization and repeated use

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If templates are bent manually or with tools in the operating room, then adaptability is improved, but device complexity increases due to need for bending tools and procedures

Engineering Contradiction:

Improveshape customizationVSAvoidbending procedure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the temperature parameter of the shape memory alloy to enable bending at operating room temperature in the martensite phase. This eliminates the need for complex heating equipment or specialized bending tools, simplifying the overall device complexity while maintaining full adaptability for shape customization

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 template can be safely reused multiple times, maintaining accurate anatomical contours and reducing the risk of breakage, while allowing for easy reproduction of complex shapes and improved surgical precision.

Implementation Method 1

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Data Source

PatentUS10092335B2Method of using template in manufacturing an implant for spinal or other orthopedic fixation

Publication Date: 2018.10.09 BIEDERMANN TECH GMBH & CO KG

AI summary

A template for use in producing an implant for use in spinal or other orthopedic fixation is provided, where the template is adjustable between a first configuration in which the template is capable of bending in response to a force and is capable of retaining a bent shape, and a second configuration in which the template assumes a memorized shape in response to directing the temperature of the template to value that is at or above a recovery level, where the recovery level is above body temperature. A spinal or orthopedic implant is formed by duplicating the bent shape of the template.