Spine Plate Bone Screw Bore Angulation and Retention
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Solution Overview
Problem
Current spine plates require additional components like caps or prong structures to prevent bone screw rotation and lack optimal geometry for bone screw angulation, complicating the fixation process and fusion procedures.
Innovation Solution
The spine plate features bone screw bores with arcuate lips and spherical sidewalls, allowing for snap retention and providing 10° to 30° angulation ranges, eliminating the need for extra components and enhancing screw stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If caps or prong structures are added to prevent bone screw rotation, then bone screw retention is improved, but device complexity increases
Solution Approach 1:
The patent combines the bone screw retention function and anti-rotation function into a single integrated bore structure. The spherical sidewalls with equatorial protrusion create an interference fit that simultaneously prevents screw rotation and secures the screw to the plate, eliminating the need for separate caps or prong structures.
Solution Approach 2:
The patent extracts the retention and anti-rotation functions from separate components (caps, prongs) and integrates them directly into the bore geometry itself. The bore's spherical sidewalls and equatorial protrusion are designed to provide both functions inherently, removing unnecessary extra components from the assembly.
2Adaptability or versatility
If bone screw bores are designed for angulation, then surgical adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs spherical sidewalls within the bore to enable angulation of the bone screw. The spherical geometry allows the screw to be inserted at various angles while maintaining secure retention, as the spherical surface can accommodate angular variations while the equatorial protrusion provides a stopping point for proper positioning.
3Ease of operation
If the plate design is simplified to eliminate extra components, then ease of operation is improved, but bone screw retention reliability may worsen
Solution Approach 1:
The patent merges multiple functions (retention, anti-rotation, angulation accommodation) into the bore structure itself, eliminating extra components while maintaining or enhancing reliability. The spherical sidewalls with equatorial protrusion provide interference fit retention and prevent screw backout without requiring separate caps or prongs.
Data Source
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AI summary
A spina plate defines a body having a posterior surface or side and an anterior surface or side The body also has a pair of bone screw bores for each vertebra to which the spine plate will be attached The bone screw bores extend between the posterior side and the anterior side A relief area is provided between each pair of bone screw bores in the anterior surface of the body The relief area opens to both bone screw bores to allow displacement of the bone screw when entering the respective bone screw bore The relief area also opens to both bone screw bores to permit an instrument to be received therein to remove a bone screw from one of the bone screw bores.