Facet Arthroplasty Device for Adjacent Level Stress Reduction
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Solution Overview
Problem
Existing spinal fusion techniques lead to increased stresses on adjacent vertebrae, causing 'adjacent-level disease' due to reduced motion at fused spinal levels, which can result in further surgical interventions and multiple-level fusions, and there is a need for devices that can stabilize and restore motion to affected segments.
Innovation Solution
A facet joint replacement system with modular, adaptable components that can be attached to existing spinal hardware, providing stabilization and motion restoration by articulating between adjacent vertebrae, allowing for selective attachment to various anatomical structures and existing instrumentation, thereby addressing stress distribution and motion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If spinal fusion is performed to stabilize the spine, then spinal stability is improved, but stress on adjacent vertebrae increases causing adjacent-level disease
Solution Approach 1:
The device segments the spinal stabilization function by providing independent articulating components at adjacent vertebrae that can move relative to each other, while still being connected to the fused spinal segment. This allows the fused segment to remain stable while adjacent segments can articulate, distributing stress more evenly across multiple levels rather than concentrating it at single adjacent vertebrae.
Solution Approach 2:
The device introduces dynamic articulating components with rotational and translational degrees of freedom that allow adjacent vertebrae to move relative to the fused segment. This dynamic capability enables the spine to adapt to physiological loads and motions, reducing stress concentration on adjacent vertebrae while maintaining overall spinal stability through the connected fusion hardware.
2Stability of the object's composition
If motion is limited at fused spinal levels, then spinal stabilization is achieved, but natural motion is lost at those levels
Solution Approach 1:
The device transfers motion from the fused spinal level to adjacent dimensions by providing articulating components at vertebrae above and below the fusion. These components allow rotation and translation in multiple degrees of freedom, effectively moving the motion capability to a different spatial location while the fused segment itself remains stabilized.
Solution Approach 2:
The articulating components serve as intermediaries between the fused spinal segment and adjacent vertebrae. These components include rotation members with articulating surfaces and translation members that mediate the interaction between fixed and mobile segments, allowing controlled motion transmission while maintaining stabilization at the fusion site.
3Stability of the object's composition
If multiple-level fusions are performed to treat adjacent-level disease, then spinal stability is improved, but device complexity and surgical intervention increase
Solution Approach 1:
The device provides multi-functionality by combining fusion hardware attachment capabilities with articulating components that can provide both stabilization and controlled motion. This single device structure can address multiple functional requirements (stabilization, motion preservation, stress distribution) without requiring separate devices for each level, thereby reducing overall system complexity compared to multiple independent fusion constructs.
Data Source
AI summary
The invention discloses an implantable facet arthroplasty device suitable for treating adjacent level disease. The device is designed for implantation between a first vertebra and a second vertebra. Components of the device include: a crossbar; a first component having a first attachment mechanism adapted to attach to a first location of a spinal fusion device attached to a first vertebra and a second attachment mechanism adapted to attach to the crossbar; and a second component having a second attachment mechanism adapted to attach to a second location of a spinal fusion device attached to the first vertebra and a second attachment mechanism adapted to attach to the crossbar. The first component articulates relative to the second component and the first vertebra articulates relative to the device itself.