Variable-Pitch Surgical Screw for Compression and Plate Locking
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Solution Overview
Problem
Existing surgical fixation methods for fractured bones often fail to provide both effective compression and locking mechanisms efficiently, leading to suboptimal healing and stability.
Innovation Solution
A surgical screw system featuring a bone plate and a surgical screw with a variable pitch thread that combines compression and locking functions, where the screw's shaft portion applies variable pitch threading to draw bone fragments together and the head portion locks the plate to the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate compression screws and locking screws are used, then compression and locking functions are achieved, but device complexity increases and surgical time increases
Solution Approach 1:
The patent combines compression and locking functions into a single screw design. The screw features a shaft portion with threads for compression and a head portion with a locking mechanism, eliminating the need for separate compression and locking screws. This reduces the number of components and surgical steps while maintaining both compression and locking capabilities.
Solution Approach 2:
The single screw design performs multiple functions: it provides compression through its threaded shaft portion and simultaneously provides locking through its head portion mechanism. This multi-functional design replaces what previously required two separate specialized screws, simplifying the overall fixation system.
2Reliability
If multiple surgical steps are used for compression and locking, then both functions are achieved, but surgical time increases
Solution Approach 1:
The patent merges the compression application step and the locking step into a single simultaneous action. As the single screw is inserted and tightened, the shaft portion compresses the bone fragments while the head portion locks to the bone plate, achieving both functions in one surgical step rather than requiring separate sequential steps.
Solution Approach 2:
The screw design incorporates pre-configured compression and locking features that activate automatically during insertion. The variable pitch threads and head portion geometry are designed to provide compression and locking actions as inherent parts of the insertion process, eliminating the need for additional adjustment steps.
3Device complexity
If a single screw provides both compression and locking, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The screw features variable pitch threads where the pitch changes along the length of the shaft portion. This allows different sections of the screw to have optimized thread characteristics for their specific functions, with precise pitch variations engineered into specific zones to achieve both compression and locking effects with appropriate local thread geometries.
Solution Approach 2:
The patent employs variable pitch threading where the thread pitch parameter changes along the shaft length. This parameter variation allows the screw to provide different mechanical effects at different locations - finer pitch for compression in some regions and coarser pitch for locking engagement in others - thereby achieving dual functionality through controlled parameter changes rather than requiring multiple separate components.
Data Source
AI summary
A surgical screw according to an exemplary aspect of the present disclosure includes, among other things, a shaft portion that extends between a proximal end and a distal end, the shaft portion including a first thread having a variable pitch and a head portion extending from the proximal end of the shaft portion. The head portion includes a second thread having a pitch that is equal to a pitch of at least a portion of the variable pitch.