Segmented Fixation Element Anchorage in Bone
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Solution Overview
Problem
Existing bone fixation devices with heat-bondable materials face challenges in achieving adequate anchorage in poor bone quality, as the softened material may not provide sufficient mechanical stability and can lead to migration of the suture.
Innovation Solution
An elongated fixation element with a non-absorbent distal and proximal section and an absorbent middle section, which is made of thermoplastic material that softens upon electromagnetic radiation, allowing it to expand and anchor securely into the bone while maintaining mechanical strength in the distal section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixation element is made entirely of heat-bondable material to enable softening and expansion into bone, then anchorage capability is improved, but mechanical strength and stability are compromised
Solution Approach 1:
The fixation element is divided into three distinct sections along its longitudinal axis: a distal section made of non-absorbent material for mechanical strength, a middle section made of heat-bondable material for anchorage, and a proximal section made of non-absorbent material for structural support. This segmentation allows each section to fulfill its specific functional requirement without compromising the overall device performance.
Solution Approach 2:
Different material properties are assigned to different sections of the fixation element. The distal and proximal sections use non-absorbent materials with high mechanical strength, while the middle section uses heat-bondable material with softening capability. This local differentiation of material quality enables the device to simultaneously achieve mechanical integrity and anchorage functionality.
2Reliability
If the entire fixation element is softened by electromagnetic radiation to expand into bone, then anchorage is improved, but the distal tip loses mechanical integrity and cannot be properly impacted
Solution Approach 1:
The fixation element is segmented into radiation-absorbent and radiation-transparent sections. The middle section contains material that absorbs electromagnetic radiation and softens, while the distal section contains material that is transparent to radiation and maintains mechanical integrity during impact. This segmentation allows selective softening of only the anchorage portion.
Solution Approach 2:
The distal section acts as an intermediary that protects the softened middle section during the impacting process. By being transparent to electromagnetic radiation, it allows radiation to pass through to soften the middle section, while simultaneously providing the mechanical strength needed for cortical penetration. This intermediary structure resolves the conflict between softening requirement and impact strength requirement.
3Reliability
If heat-bondable material is used throughout the fixation element, then expansion into bone is improved, but suture stability and prevention of migration are compromised
Solution Approach 1:
The fixation element is segmented into a middle section made of heat-bondable material for expansion and anchorage, and distal/proximal sections made of non-absorbent material for structural stability. This segmentation ensures that only the necessary portion expands into the bone while the suture-containing sections maintain their structural integrity and prevent migration.
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 elongated fixation element can be effectively anchored in bones of varying quality, providing stable anchorage without compromising the mechanical integrity of the distal section, thus enhancing the fixation process.
Implementation Method 1
the middle section comprises a material which is absorbent for electromagnetic radiation
Implementation Method 2
the material of the middle section is a thermoplastic material
Implementation Method 3
the proximal section is made of a material that is non-absorbent for electromagnetic radiation; the distal section is made of a material that is non-absorbent for electromagnetic radiation
Data Source
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AI summary
A fixation device, comprises an elongated element extending along a central axis, having a total length L and including a proximal section formed of a material that is substantially non-absorbent for electromagnetic radiation within a preselected wavelength range and a distal section formed of a material that is substantially non-absorbent for electromagnetic radiation within the preselected wavelength range in combination with a middle section axially arranged between the proximal and distal sections, the middle section formed of a material that is substantially absorbent for electromagnetic radiation in the preselected wavelength range.