Self-Locking Orthopedic Plate Mechanism for Cervical Screw Retention
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Solution Overview
Problem
Current anterior cervical plates face issues with screws backing out, requiring complex locking mechanisms and increasing the plate's thickness, which can cause patient discomfort and prevent proper neck stabilization.
Innovation Solution
A self-locking mechanism with a tapered aperture and sliding locking mechanism that automatically secures fasteners without the need for additional washers or complex locking steps, allowing for constrained or semi-constrained screw orientations and visual inspection post-surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to prevent screw backing out, then screw retention reliability is improved, but device complexity increases
Solution Approach 1:
The locking mechanism is designed to automatically engage and lock screws in place without requiring additional components, complex assembly steps, or external actuation. The mechanism self-activates during the screw insertion process, eliminating the need for separate locking operations and reducing overall device complexity while maintaining reliable screw retention.
Solution Approach 2:
The locking function is integrated directly into the plate structure by combining the locking mechanism with the plate body and aperture system. This merging eliminates the need for separate locking components and reduces the number of parts, thereby decreasing device complexity while ensuring reliable screw retention through the unified design.
2Reliability
If a locking mechanism is added to prevent screw backing out, then screw retention reliability is improved, but plate thickness increases
Solution Approach 1:
The locking mechanism is nested within the plate thickness, with components arranged concentrically or in layered configurations that minimize the overall dimensional increase. This nesting approach allows the locking function to be incorporated without significantly increasing plate thickness, maintaining profile compatibility while ensuring reliable screw retention.
Solution Approach 2:
The locking mechanism utilizes the depth dimension of the plate aperture and utilizes three-dimensional spatial arrangement to achieve locking functionality without increasing the plate's external thickness. By engaging components in the depth dimension rather than expanding the plate's overall thickness, the design maintains a thin profile while providing reliable screw retention.
3Reliability
If additional washers or locking steps are used, then screw retention reliability is improved, but ease of operation deteriorates
Solution Approach 1:
The locking mechanism automatically engages and locks screws in place during the insertion process without requiring additional washers, separate locking steps, or manual intervention. This self-locking capability simplifies the installation procedure, improving ease of operation while maintaining reliable screw retention through the automated locking action.
Solution Approach 2:
The locking mechanism is pre-configured and positioned within the plate structure before screw insertion, so that the locking action occurs automatically as part of the normal installation process. This preliminary positioning eliminates the need for additional washers or separate locking steps, simplifying the installation procedure while ensuring reliable screw retention through the pre-arranged locking geometry.
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
The solution ensures screws remain securely in place, reducing patient discomfort and maintaining neck stability while allowing for easy installation and verification of locking status via fluoroscopy, without increasing the plate's thickness or requiring additional components.
Implementation Method 1
The tapered top surface may be operable to interact with a fastener as the fastener is being inserted into the aperture longitudinally, the insertion of the fastener operable to cause the locking mechanism to slide laterally along the slot away from the aperture
Implementation Method 2
the locking mechanism comprises a pair of compressible flanges received in recess slots defined in sidewalls of the slot
Data Source
AI summary
Disclosed embodiments relate to an orthopedic device including a plate and a single-step self-locking mechanism. The plate includes one or more tapered apertures and a slot defined in a top surface of the plate, the slot extending from each aperture. The locking mechanism is slidably seated in the slot and is operable to be positioned in a first position along the slot where a portion of the locking mechanism extends over the aperture or positioned in a second position along the slot where the portion of the locking mechanism is fully retracted from the aperture.