Variable-Pitch Surgical Screw for Combined Compression and Locking
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Solution Overview
Problem
Existing surgical screw systems fail to effectively combine the functions of compression and locking in a single screw design, leading to inadequate stabilization and healing of fractured bones.
Innovation Solution
A surgical screw system featuring a bone plate with threaded openings and a surgical screw with a shaft portion having a variable pitch thread, allowing both compression and locking functions, where the screw's head portion and shaft portion share the same thread pitch, and the shaft thread pitch varies along its length to enhance compression and locking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a surgical screw system uses a constant pitch thread, then the manufacturing is simple, but the compression and locking functions cannot be effectively combined
Solution Approach 1:
The thread pitch varies along the length of the screw shaft, with different pitch values in different regions. The first pitch in the first region provides compression function, while the second pitch in the second region provides locking function. This local differentiation of thread properties enables the single screw to perform multiple functions simultaneously.
Solution Approach 2:
The screw shaft is divided into multiple regions with different thread pitch characteristics. The first region has a first pitch optimized for compression, while the second region has a second pitch optimized for locking. This segmentation allows each region to independently perform its specific function while working together as a unified system.
2Ease of manufacture
If separate compression and locking screws are used, then each function can be optimized independently, but the device complexity and number of components increases
Solution Approach 1:
The invention merges the compression screw and locking screw into a single integrated screw component. By incorporating variable pitch threads along the shaft length, the single screw simultaneously provides both compression (through the first pitch region) and locking (through the second pitch region) functions, eliminating the need for separate components.
Solution Approach 2:
The surgical screw is designed as a universal component that performs multiple functions. The variable pitch thread configuration enables the same screw to provide both compression across the fracture site and locking engagement with the bone plate, making it a multi-functional tool for fracture fixation.
3Reliability
If the shaft thread pitch varies along its length, then compression and locking are enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
Different regions of the screw shaft have locally optimized thread pitches. The first region has a first pitch designed for compression with specific geometric characteristics, while the second region has a second pitch designed for locking with different characteristics. This local quality differentiation enhances the reliability of each function while allowing manufacturing to focus on precise replication of defined regional patterns.
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.