Active Compression Structures with SMA for Small-Bone Fusion
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Solution Overview
Problem
Current bone fusion devices, such as active compression screws, are limited in their ability to adjust compression over time, have complex constructions, and cannot be scaled down for small bones, leading to inefficient bone healing and increased surgical complexity.
Innovation Solution
The development of active compression apparatuses with a unitary contiguous structure, utilizing materials like Shape Memory Alloy (SMA) and mechanisms such as perforations or cut features, allows for adjustable axial tension and compression forces that can be applied before, during, or after deployment, accommodating different surgical procedures and bone sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard screw compression is used, then bone fragments are held in place, but the device cannot maintain compressive load dynamically as bone remodels
Solution Approach 1:
The patent transforms the static screw compression system into a dynamic one by incorporating an expandable balloon catheter that can be inflated and deflated to adjust compressive forces. The balloon's expansion against the bone fragments provides continuous, adjustable compression that adapts as bone remodels, converting a fixed mechanical system into a controllable dynamic system.
Solution Approach 2:
The balloon catheter serves as an intermediary element between the surgeon's control and the bone fragments. Instead of directly adjusting screw compression, the surgeon inflates or deflates the balloon to mediate the compressive force application, providing smooth, continuous adjustment without mechanical complexity.
2Force
If active compression screw concepts are used, then axial tension capability is provided, but the surgical procedures become complicated
Solution Approach 1:
The patent extracts the compression function from complex threaded mechanisms and concentrates it in a simple balloon element. The balloon catheter removes the need for intricate active compression screw mechanisms while maintaining axial tension capability through pneumatic expansion, simplifying the overall device construction.
Solution Approach 2:
The patent replaces mechanical threaded compression systems with a pneumatic system. Instead of using complex screw threads and mechanical advantage mechanisms to generate axial tension, the invention uses balloon inflation pressure to directly apply compressive force, substituting a simpler pneumatic mechanism for complex mechanical systems.
3Force
If current active compression screws are used, then compression force is applied, but the devices cannot be scaled down for small bones
Solution Approach 1:
The patent enables size scalability by changing the fundamental parameter of compression application from mechanical thread pitch to balloon internal pressure. The balloon catheter can be manufactured in various sizes suitable for different bone dimensions, and the compressive force can be adjusted independently of device size through pressure control, allowing the same basic design to scale from large to small bones.
4Ease of manufacture
If standard screws are used, then simple construction is achieved, but the compressive load cannot be adjusted over time
Solution Approach 1:
The patent combines the simplicity of a basic catheter structure with multiple functions: the balloon provides both structural support and adjustable compression, the catheter serves as both delivery vehicle and control mechanism, and the entire device can be deployed through minimally invasive techniques. This multi-functionality maintains construction simplicity while adding adjustment capability.
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
These devices provide continuous axial tension over a range of 1%-20% of the member's length, delivering compressive forces of 0-200N, adjustable over time, and can be scaled down for small bones, enhancing bone fusion and healing by maintaining optimal compressive loads.
Implementation Method 1
The implant comprises a shaft including a longitudinal axis, a proximal portion, an expandable center section or portion and a distal portion
Implementation Method 2
utilizing materials like Shape Memory Alloy (SMA)
Implementation Method 3
a central portion interposed between the proximal bone engagement portion and the distal bone engagement portion that facilitates a change in a dimension of the apparatus
Data Source
AI summary
Compression devices for joining tissue and methods for using and fabricating the same.