Headless Compression Screw With Segmented Threads
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Solution Overview
Problem
Existing bone screws with different thread pitches complicate the separate execution of setting, compressing, and recessing bone fragments, as the steps are often intertwined, and the interaction between thread segments can lead to instability in fragment fixation.
Innovation Solution
A bone screw design featuring two coaxially disposed threaded segments with identical or different pitches, allowing for separate and controlled steps of setting, compressing, and recessing bone fragments, with a middle threadless segment for enhanced stability, and a surgical instrument with a complementary internal thread for precise implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the two external threads have different pitches, then the bone screw can perform multiple functions (setting, compressing, recessing) in a single design, but the steps for implantation, setting, compressing, and recessing cannot be carried out separately from one another
Solution Approach 1:
The bone screw is divided into two distinct threaded segments with different pitch characteristics. The first threaded segment has a pitch adapted for initial implantation and setting, while the second threaded segment has a different pitch optimized for compression and recessing operations. This segmentation allows each segment to independently perform its specific function without interfering with the other, enabling separate and controlled execution of implantation steps.
2Stability of the object's composition
If the middle segment diameter corresponds to the external diameter of the external thread, then lateral stabilization of bone fragments is improved, but the interaction between thread segments may lead to instability in fragment fixation
Solution Approach 1:
The middle segment is designed with a specific diameter that corresponds to the external diameter of the external thread at the distal threaded segment, creating a localized expansion zone. This local quality change provides lateral stabilization of bone fragments at the fracture site while the different pitch configurations of the two threaded segments prevent unwanted interaction and maintain reliable fragment fixation throughout the implantation process.
3Ease of operation
If the front threaded segment is screwed into the distal bone fragment while the rear threaded segment is screwed into the implantation instrument, then separate control of implantation steps is achieved, but the rear threaded segment must have a larger core diameter to avoid thread interference
Solution Approach 1:
The bone screw is divided into two distinct threaded segments with different pitch characteristics. The first threaded segment has a pitch adapted for initial implantation and setting, while the second threaded segment has a different pitch optimized for compression and recessing operations. This segmentation allows each segment to independently perform its specific function without interfering with the other, enabling separate and controlled execution of implantation steps.
Data Source
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Figure 3A~3C
AI summary
A bone screw (1) is provided having first (5) and second (7) threaded portions of different diameter separated by a middle portion (6) that is unthreaded so that the bone screw may be inserted into a pair of adjacent bone fragments and used to compress the fragments together by driving the screw into a hole drilled in the fragments. An installation tool (15) is also disclosed for threadably engaging one end of the bone screw and is used to initially drive the screw into the bone hole. Thereafter, a screwdriver (16) is inserted through the tool and into engagement with a recess (11) in the bone screw and may be used to drive the screw fully into the bone and to separate the bone screw from the installation tool.