Expandable Intervertebral Spacer with Rotating Arms
Find Innovative SolutionsGenerate Solutions
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 provide stable vertebral support, then stabilization effectiveness is improved, but the spacer cannot be inserted via posterior approach without damaging nerve roots
Solution Approach 1:
The spacer is divided into a body portion and multiple deployable arm portions. The body 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 the entire spacer to be wide during insertion.
Solution Approach 2:
The spacer transitions from a compact configuration during insertion to an expanded configuration after placement. The arms are movable from a retracted position (during insertion) to a deployed position (after placement), allowing the spacer to adapt its width dynamically to avoid nerve root damage during insertion while providing adequate support after placement.
2Ease of operation
If the spacer width is reduced to fit between nerve roots, then ease of insertion is improved, but the base support area is insufficient for stable vertebral stabilization
Solution Approach 1:
The arms are nested within or alongside the body during insertion, with the arms having a width less than the body width when retracted. This allows the entire spacer assembly to pass through the narrow space between nerve roots. After insertion, the arms are deployed outward to increase the overall width and provide adequate base support area for vertebral stabilization.
Solution Approach 2:
The spacer utilizes lateral deployment of arms perpendicular to the insertion direction. The arms extend in a direction substantially perpendicular to the long axis of the body, increasing the width dimension after insertion without requiring the insertion path to be widened. This dimensional transformation allows the spacer to achieve sufficient support area after placement while maintaining a narrow insertion profile.
3Ease of manufacture
If fixed-width spacers are used, then manufacturing simplicity is improved, but adaptability to varying intervertebral spaces is reduced
Solution Approach 1:
The spacer incorporates movable arms that can be deployed to different extents, allowing the overall width and height to be adjusted according to the specific intervertebral space requirements. The arms can be positioned at various angles and extensions, providing adaptability to different patient anatomies while using a standardized body component that simplifies manufacturing.
Solution Approach 2:
The spacer allows adjustment of geometric parameters (width, height, arm angle) after the basic component is manufactured. By changing the deployment state of the arms, the effective dimensions of the spacer can be modified to match the specific intervertebral space being treated, providing versatility without requiring multiple fixed-size spacer variants.
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 stable vertebral stabilization without damaging nerve roots, allowing for broader base support and adjustable height and width to match the intervertebral space, reducing the need for nerve root retraction during spacer insertion.
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.