Dynamic Bone Compression Implant With Sustained Superelastic Tension
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Solution Overview
Problem
Existing compression devices for bony fractures fail to provide sustained and dynamic compressive forces due to resorption and resettlement of bony fragments, leading to insufficient healing and potential need for revision surgery.
Innovation Solution
A compression device with a threaded body and sliding element, connected by a superelastic compression element, applies sustained tension to bony fragments through a cannulated design that allows for pre-stretching and configuration of compression levels without altering the device's footprint, using materials like titanium and nitinol to maintain continuous compressive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a threaded compression device is inserted into two bony fragments to generate compressive force, then the initial compressive force is sufficient, but the compression becomes insufficient or discontinuous due to bone resorption and resettlement
Solution Approach 1:
The compression device transitions from a static threaded design to a dynamic system using a shape memory alloy wire that can automatically adjust and maintain compressive force. The wire undergoes phase transformation in response to temperature changes, enabling it to dynamically compensate for bone resorption and resettlement, thereby sustaining compression over an extended period without requiring manual adjustment.
Solution Approach 2:
The device utilizes temperature as a control parameter to trigger phase transformation in the shape memory alloy wire. By changing the temperature (e.g., through body heat or external heating), the wire transitions between austenite and martensite phases, which changes its mechanical properties and enables it to exert or release compressive force as needed to maintain sustained compression.
2Reliability
If a threaded compression device is used to compress bony fragments, then initial compression is achieved, but the device cannot adapt to changes at the insertion site
Solution Approach 1:
The shape memory alloy wire acts as a self-adjusting mechanism that automatically responds to changes in the bone fracture environment. As the bone fragments undergo resorption or resettlement, the wire detects the dimensional changes and autonomously adjusts its compression force through phase transformation, eliminating the need for external intervention or manual recalibration by medical personnel.
Solution Approach 2:
The system establishes a feedback loop where the physical state of the bone fragments (distance between them) directly influences the state of the shape memory alloy wire. The wire continuously monitors the spatial relationship between bone fragments and adjusts its compression force accordingly, creating a closed-loop control system that maintains optimal healing conditions.
3Device complexity
If the compression device is made static, then the structure is simple, but the compression force dissipates due to bone resorption
Solution Approach 1:
The device employs a shape memory alloy wire that changes its physical state through temperature-induced phase transformation. This parameter change enables the wire to transition between a compliant state (during insertion) and an active compression state (after deployment), providing sustained adaptive compression without significantly increasing structural complexity.
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 device provides precise and accurate sustained compression, adapting to bone resorption and resettlement, enhancing fracture healing without the need for additional interventions.
Implementation Method 1
a compression element connecting the threaded body and the sliding element... the compression element applies sustained tension to the sliding element and opposing tension to the threaded body, thereby compressing the first bony fragment and the second bony fragment
Implementation Method 2
the compression element stretches prior to insertion of the compression device to a target site... allowing for movement of the threaded body toward the sliding element in response to the contraction of the compression element from the stretched state
Data Source
AI summary
A compression device may include, but is not limited to, a threaded body, a sliding element, and a compression element connecting the threaded body and the sliding element. According to one embodiment, upon implantation, the threaded body contacts a first bony fragment and the sliding element contacts to a second bony fragment. In at least one embodiment, upon being engaged, the compression element applies sustained tension to the sliding element and opposing tension to the threaded body, thereby compressing the first bony fragment and the second bony fragment along a plane of contact promoting healing.