Spinal Facet Fastener for Joint Stabilization
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Solution Overview
Problem
Facet joints in the spine often degenerate with age, leading to pain and instability, as the intervertebral disc degenerates and the facet joints experience increased stress, necessitating a device to restrict or immobilize spinal facet joints due to disease, injury, or trauma.
Innovation Solution
A spinal facet fastener, made from biocompatible materials like PEEK, titanium, or stainless steel, is designed to clamp, staple, or retain vertebral bone segments, limiting flexion and extension, or immobilizing movement by abutting vertebral bone surfaces or being anchored between them, with configurations such as U-shaped bodies or spiked elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intervertebral disc degenerates and loses height, then the disc space narrows and provides less support for facet joints, but the facet joints become subject to increased stress and degeneration
Solution Approach 1:
The spinal facet fastener acts as an intermediary device between the degenerating disc and facet joints. It provides mechanical support to the facet joints directly, compensating for the lost disc support and reducing the stress that would otherwise be transmitted to the facet joints during spinal motion.
Solution Approach 2:
The fastener changes the mechanical parameters of the facet joint by providing external support and constraint. It modifies the load distribution and stress patterns acting on the facet joints, reducing the harmful stresses caused by disc degeneration while maintaining necessary joint function.
2Ease of operation
If facet joints are left to move freely, then natural motion is maintained, but pain and instability occur due to degeneration and arthritis
Solution Approach 1:
The fastener is designed to be dynamic rather than completely rigid. It allows controlled motion of the facet joints while providing stability, adapting to the natural range of motion while preventing harmful movements that cause pain and further degeneration in arthritic joints.
3Reliability
If a spinal facet fastener is inserted to restrict joint movement, then stability is improved and pain reduced, but the device complexity and surgical intervention requirements increase
Solution Approach 1:
The fastener is segmented into multiple functional components including compression elements, positioning features, and attachment mechanisms. This segmentation allows each component to perform its specific function efficiently while enabling modular design that simplifies manufacturing and surgical implantation.
4Reliability
If the fastener applies compression to restrict motion, then joint stability improves, but the force required to maintain compression increases
Solution Approach 1:
The fastener utilizes periodic action through its ratchet or cam mechanism that allows insertion with high force but maintains compression with minimal sustained force. The mechanism converts intermittent high-force application during implantation into continuous low-force maintenance, reducing the ongoing force requirement while maintaining joint stability.
Data Source
AI summary
A spinal implant includes a first leg configured to abut a surface of an inferior articular process of a first vertebra that forms one portion of a spinal facet joint between the first vertebra and an adjacent second vertebra, a second leg configured to abut a surface of a superior articular process of the adjacent second vertebrae that forms another portion of the spinal facet joint between the first vertebra and the adjacent second vertebra, and a cross-member connected between the first and second legs and maintaining the first and second legs in a spaced-apart relationship. The spinal implant may restrict flexion and/or extension of the spinal facet joint when received about the spinal facet joint.