Expandable Intervertebral Spacer with Central Gear Deployment
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Solution Overview
Problem
Current surgical techniques for inserting intervertebral spacers via a posterior approach often damage nerve roots due to their width being wider than the space between nerve roots, requiring retraction of these roots for spacer insertion.
Innovation Solution
An expandable intervertebral spacer with rotatable L-shaped arms that retract within the body to fit between nerve roots and deploy once inside, increasing height and width to stabilize vertebrae without needing nerve root retraction, utilizing a central gear mechanism for simultaneous deployment of arms in alternating directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a spacer of sufficient width is used to stabilize vertebrae, then stabilization effectiveness is improved, but the spacer cannot be inserted without retracting nerve roots
Solution Approach 1:
The spacer is divided into a body portion and multiple deployable arms. The body portion has a narrow width for insertion between nerve roots, while the arms can be deployed laterally to increase the overall width and provide stable vertebral support without requiring nerve root retraction.
Solution Approach 2:
The arms are nested within the body portion during insertion, allowing the spacer to pass between nerve roots in a compact configuration. After insertion, the arms are deployed outward from the body to achieve the required width for stabilization.
2Ease of operation
If the spacer width is reduced to fit between nerve roots, then insertion without retraction is enabled, but the base for stabilization becomes insufficient
Solution Approach 1:
The spacer transitions from a static narrow configuration during insertion to a dynamic expanded configuration after insertion. The arms are deployable and adjustable, allowing the spacer to adapt its width to provide adequate stabilization base while maintaining ease of insertion.
Solution Approach 2:
The spacer utilizes the lateral dimension by deploying arms perpendicular to the insertion direction. This allows the spacer to maintain a narrow profile in the insertion direction (fitting between nerve roots) while expanding in the lateral dimension to provide sufficient stabilization base.
3Stability of the object's composition
If multiple arms are deployed in alternating directions, then symmetric expansion is achieved, but complex deployment mechanism is required
Solution Approach 1:
Multiple arm deployment mechanisms are merged into a single integrated system. A central gear mechanism controls the deployment of all arms simultaneously, coordinating their motion in alternating directions to achieve symmetric expansion without requiring separate control systems for each arm.
Solution Approach 2:
A central gear acts as an intermediary mechanism that translates rotational motion into coordinated lateral movement of multiple arms. The gear system synchronizes the deployment of arms in alternating directions, achieving symmetric expansion while simplifying the overall control architecture.
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 the insertion of spacers without retracting nerve roots, providing a stable base for vertebrae stabilization by expanding to match the intervertebral space dimensions, thus minimizing surgical complications and promoting effective spinal stabilization.
Implementation Method 1
utilizing a central gear mechanism for simultaneous deployment of arms in alternating directions
Data Source
AI summary
An expandable intervertebral spacer has a plurality of arms. The arms can be retracted or extended. The spacer has a width that is narrower than the width between the nerve roots near the posterior approach to an intervertebral space. Once inserted into the intervertebral space, the arms can be deployed. The deployed arms expand the height and width of the spacer. Once deployed, the spacer stabilizes two adjacent vertebrae. The arms are interconnected mechanically to deploy simultaneously.