Expandable Interbody Spacer Quadrant Cam Mechanism
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Solution Overview
Problem
Current interbody spacers for spinal fusion require large sizes that cause extensive tissue disruption and trauma during placement, as they need to support the spinal column during bone remodeling, and existing minimally invasive techniques still face challenges in reducing soft tissue displacement and site preparation trauma.
Innovation Solution
An expandable intervertebral spacer that transforms from a compact cylindrical shape to a cuboidal shape, utilizing a system of quadrants and linking members with a cam action mechanism for controlled expansion, allowing percutaneous insertion and providing structural integrity for spinal support during fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large interbody spacer is used to support the spinal column during bone remodeling, then structural integrity and stability are improved, but tissue disruption and trauma during placement increase
Solution Approach 1:
The interbody spacer is designed to be expandable, transitioning from a compressed insertion configuration to an expanded support configuration. This dynamic transformation allows the device to start small for minimal tissue disruption during insertion, then expand to provide the necessary structural integrity and stability for spinal support during bone fusion.
Solution Approach 2:
The spacer body is divided into multiple quadrants that can slide relative to each other along ramp portions. This segmentation allows the structure to be compressed for insertion and then expanded through the sliding mechanism to achieve the full support configuration, resolving the contradiction between size and tissue trauma.
2Stability of the object's composition
If a large interbody spacer is used to maintain spinal space during fusion, then stability during fusion is improved, but site preparation requirements increase
Solution Approach 1:
The expandable design allows the spacer to be inserted in a compressed state through minimal site preparation, then expanded in-situ to achieve the stable configuration needed for spinal support during fusion, eliminating the need for extensive preoperative site preparation for large implants.
Solution Approach 2:
The spacer is pre-compressed to a small insertion configuration for easy placement through minimal incisions, then expanded to the full size needed for stability during fusion. This preliminary compression action allows minimal site preparation while achieving the required stability.
3Strength
If a large interbody spacer is used to support vertebral bodies, then fusion support is improved, but soft tissue displacement increases
Solution Approach 1:
The dynamic expansion capability allows the spacer to provide minimal interference with soft tissues during insertion, then expand to provide full vertebral body support during fusion. This temporal separation of functions minimizes soft tissue displacement while maintaining fusion support.
Solution Approach 2:
The segmented quadrant design with sliding portions allows controlled expansion that can be directed to expand the spacer body while minimizing displacement of surrounding soft tissues, achieving fusion support with reduced harmful effects.
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 expandable spacer minimizes tissue disruption and trauma by enabling smaller initial insertion with controlled expansion to support the spinal column, maintaining stability and structural integrity during bone fusion while reducing the need for extensive site preparation and minimizing soft tissue displacement.
Implementation Method 1
utilizing a system of quadrants and linking members with a cam action mechanism for controlled expansion
Implementation Method 2
A tension member couples the first quadrant and the second quadrant
Implementation Method 3
A plurality of integral linking members couple the proximal and distal ends with the body
Data Source
Figure 1
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AI summary
An expandable intervertebral spacer includes a body, a proximal end, and a distal end. The body includes quadrants that form a substantially cylindrical shape in a first configuration and a substantially cuboidal shape in a second configuration. Each quadrant includes a ramp portion with a ramp and a landing and a sliding portion with a sliding side and a foot. The ramp portion of a first quadrant engages the sliding portion of a second quadrant. The proximal end and the distal end couple with the plurality of quadrants and transfer an actuating force to expand the body from the first configuration to the second configuration.