Osteosynthesis Screw Recess Indexing for Precise Orientation
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Solution Overview
Problem
Existing osteosynthesis screws face challenges in maintaining orientation during minimally invasive surgery due to concealed beveled rear faces, requiring additional operations or imaging for re-orientation, and standard instruments often lack compatibility for removal.
Innovation Solution
A tightening screw with a recess featuring angularly distributed regular shapes, including indexing lobes, allows unique orientation using standard screwdrivers and visual marks, ensuring compatibility with standard tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a beveled rear face is used on the screw to conform to bone contour, then tissue damage is limited, but the rear face becomes concealed during minimally invasive surgery requiring additional operations or imaging for re-orientation
Solution Approach 1:
The screw's own recess structure provides self-indexing capability through its geometric features (convex lobes, concave lobes, or flat bottom configuration), allowing the screw to automatically maintain or restore its correct orientation without requiring external imaging or additional surgical operations. The recess acts as a self-contained orientation reference system.
2Manufacturing precision
If a specialized screwdriver with visual marks is used to maintain screw orientation, then screw orientation is controlled, but the device complexity increases and compatibility with standard instruments is reduced
Solution Approach 1:
The recess structure serves as an intermediary element that translates orientation information from the screw to the screwdriver interface. The geometric features of the recess (convex lobes, concave lobes, or flat bottom) act as a mediator that automatically aligns the screwdriver with the correct orientation, eliminating the need for visual marks or complex screwdriver design.
3Manufacturing precision
If a specialized recess shape is used for indexing, then screw orientation is controlled, but compatibility with standard instruments is lost
Solution Approach 1:
The recess incorporates asymmetric geometric features (convex lobes, concave lobes, or flat bottom configuration) that provide directional indexing while maintaining overall symmetry compatible with standard instrument interfaces. The asymmetric elements within the recess create unique orientation references without preventing the use of standard screwdriver geometries.
4Manufacturing precision
If additional operations or imaging are performed to re-orient the screw, then screw orientation is restored, but surgical time and complexity increase
Solution Approach 1:
The recess is pre-configured with geometric indexing features during screw manufacturing that automatically guide correct orientation during insertion. This preliminary preparation of the recess structure eliminates the need for post-insertion orientation adjustments, imaging, or additional surgical operations to restore screw orientation.
Data Source
AI summary
The present invention relates to a clamping screw (6) for osteosynthesis, comprising at least one screw thread (7, 10) along a main axis (X) and, at its end referred to as the apex end (11), having a socket (12) which, about said main axis (A), has evenly angularly distributed shapes designed to accept complementing shapes of a screwdriver (19) engaged in said socket (12), notable in that the socket (12) of the screw (6) comprises at least three regular shapes (13) of which the vertices are inscribed inside a circle referred to as circumscribed circle (30) and at least two adjacent vertices of the socket (21) are connected to form a convex lobe referred to as indexing lobe (16) of which the radius of curvature is equal to the radius of the circumscribed circle (30).