Bone Anchoring Element with Helical Barbs
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Solution Overview
Problem
Current bone anchoring elements face challenges such as difficult insertion, high insertion force, inability to remove without damaging the bone, and lack of versatility in clinical applications.
Innovation Solution
A bone anchoring element with barb elements arranged on a helical line around the shaft axis, which reduces insertion force and increases pull-out force, allowing for secure attachment and easy removal by utilizing shape memory or superelastic materials that expand upon body heat, providing a thread-like function for positioning and easy manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bone screws and nails are used, then secure anchoring is achieved, but insertion force is high and insertion is difficult
Solution Approach 1:
The barb elements are designed to be flexible and bendable rather than rigid, allowing them to deform elastically during insertion and then spring back to provide anchoring force. This dynamic behavior enables the element to adapt to bone tissue during insertion while maintaining secure anchoring afterward.
Solution Approach 2:
The barb elements utilize shape memory alloy properties to change their physical state in response to temperature changes. The barbs transition from a compressed low-volume state during insertion to an expanded high-volume state for anchoring, utilizing the shape memory effect to reduce insertion force while maintaining anchoring strength.
2Strength
If conventional bone screws and nails are used, then secure anchoring is achieved, but removal requires destroying the bone
Solution Approach 1:
The flexible barb elements can be compressed and deformed during removal, allowing the anchoring element to be extracted from the bone without requiring destruction of the bone tissue. The same flexibility that provides anchoring strength also enables painless removal.
Solution Approach 2:
The barb elements are designed to be temporarily deformed during insertion and then recover their original shape to provide anchoring. During removal, they can be temporarily deformed again to allow extraction without bone damage, utilizing the reversible nature of elastic deformation and shape memory effects.
3Ease of operation
If wedge-shaped retention elements are used, then removal is possible, but insertion requires precise core hole diameter and is difficult
Solution Approach 1:
The barb elements provide a thread-like function through their helical arrangement and flexibility, allowing the anchoring element to be screwed inwards or backwards for positioning correction without requiring precise pre-drilled core holes. The dynamic bending of barbs creates friction and mechanical interlocking during insertion.
Solution Approach 2:
The shape memory alloy properties allow the barb elements to change their dimensional parameters in response to body temperature, expanding to provide thread-like engagement with the bone after insertion. This eliminates the need for precise core hole dimensions while maintaining easy removal capability.
4Strength
If barb elements are made rigid, then pull-out force is high, but insertion force is high and insertion is difficult
Solution Approach 1:
The barb elements are designed with controlled flexibility, bending elastically during insertion to reduce insertion force, then springing back to engage with bone tissue and provide high pull-out force. The flexibility is optimized to achieve the desired balance between easy insertion and secure anchoring.
Solution Approach 2:
The shape memory alloy properties enable the barb elements to change their stiffness and dimensional parameters based on temperature. At lower temperatures during insertion, the barbs are more compliant to reduce insertion force, then expand and stiffen in the body temperature environment to provide maximum pull-out force.
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
Enables rapid, secure, and easy insertion with reduced force, prevents loosening, and allows for removal like a screw, while being versatile for various clinical uses and easy to manufacture.
Implementation Method 1
If the barb elements are made of a shape memory alloy, the shape memory effect can be used in such a way that the barb elements do not project during insertion of the bone anchoring element into the bone and rise up when the bone anchoring element is inserted due to the action of the body heat.
Implementation Method 2
The barb elements can also be made of a material having superelastic properties or a spring like behaviour. For example a titanium alloy having superelasticity or stainless steel can be used.
Data Source
AI summary
A bone anchoring element is provided which has a shaft for anchoring in a bone. The shaft includes a tubular body having two open ends. At least one barb element is connected to the shaft. The barb element is cut into the tubular body. The barb element includes a free end and a base connecting the barb element to the shaft. The barb element has a first portion adjacent to the base and a second portion adjacent to the free end. The second portion is inclined relative to the first portion in a direction off said shaft.