Compound-Arc Splined Anchor for Spinal Fusion
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Solution Overview
Problem
Current spinal fusion devices face challenges such as difficult screw trajectories, risk of nerve root encroachment, and inadequate biomechanical fixation, leading to increased complexity and risk during spinal arthrodesis procedures, particularly in the lumbar spine, where screw protrusion can irritate vessels and esophagus, and existing devices fail to ensure proper compression for bone healing.
Innovation Solution
A stand-alone intervertebral device with angled or helical blades locked to a plating system, allowing for top-loading insertion without screw drivers, featuring a plate with angled fastener holes and splined blades that guide accurate placement, ensuring secure fixation without compromising bone contact and minimizing risk to surrounding structures, enabling fusion in compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional screws are used for spinal fixation, then spinal fusion can be achieved, but the screw trajectories are difficult to achieve and increase the risk of nerve root encroachment
Solution Approach 1:
The device segments the fixation function into multiple blades with different orientations. Each blade can be inserted through separate trajectories into different vertebral bodies, distributing the fixation function across multiple independent elements rather than relying on complex angled screws. This allows simpler insertion paths while maintaining overall fixation reliability.
Solution Approach 2:
The interbody device serves as an intermediary structure that connects the blades to each other and to the vertebral bodies. Instead of directly inserting complex angled screws into vertebral bodies, the blades connect to the interbody device which provides a stable platform, simplifying the insertion process while ensuring reliable spinal fusion.
2Reliability
If screws are driven manually with screw drivers, then fixation can be achieved, but the procedure requires hinged screw drivers and increases procedural complexity
Solution Approach 1:
The invention extracts the complex screw driving mechanism and replaces it with simpler blade insertion elements. The blades are designed to be inserted without requiring hinged screw drivers or complex manual driving tools, thereby removing the need for specialized insertion equipment while maintaining fixation reliability through the blade's structural design and engagement with the interbody device.
3Stability of the object's composition
If rigid fixation is provided, then spinal stability is achieved, but the interbody graft cannot heal in compression increasing the chance of pseudoarthrosis
Solution Approach 1:
The device provides dynamic fixation rather than rigid fixation. The blades are secured to the interbody device in a manner that allows compression forces to be transmitted to the interbody graft, enabling the graft to heal in compression. This dynamic approach maintains spinal stability while promoting fusion through compression, reducing the risk of pseudoarthrosis.
4Reliability
If blades are press-driven into vertebral bodies, then fixation is achieved, but the locking mechanism cannot be released if removal is required
Solution Approach 1:
The blades are designed with features that facilitate both insertion and removal. The pressing mechanism includes preliminary design elements such as threaded portions or engagement features that allow the blades to be securely fixed during surgery but also enable controlled removal when needed. This preliminary design consideration ensures both reliable fixation and ease of removal without requiring complex reversal procedures.
Data Source
AI summary
An intervertebral implant includes a body and a plate. The body has an upper surface defining an upper plane and a lower surface defining a lower plane. First and second fastener holes of the plate are configured to retain the heads of first and second fasteners. A portion of each of the shanks of the first and second fasteners extends from the first and second fastener holes beyond the upper plane. The shank portions of the first and second fasteners are curved in a direction away from the upper surface. The third fastener hole is configured to retain the head of the third fastener between the upper and lower planes. A portion of the shank of the third fastener extends from the third fastener hole beyond the lower plane. The shank portion of the third fastener is curved in a direction away from the lower surface.