Headless Bone Screw With Sleeve Compression Mechanism
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Solution Overview
Problem
Achieving desired compression during bone fracture reduction with headless screws is challenging, as there is no screw head to apply compressive force, leading to potential discomfort and damage to surrounding tissues, and maintaining compression is difficult.
Innovation Solution
A system comprising a screw, driver, sleeve, and locking mechanism that applies compressive force through distal threads while retaining proximal threads within the sleeve to prevent engagement with the bone, allowing for controlled compression and release of the screw flush with the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If headed screws are used to apply compressive force to bone fragments, then compression is achieved, but the screw head protrudes from the bone causing discomfort and damage to surrounding tissues
Solution Approach 1:
The invention removes the screw head from the design, extracting the problematic protruding element while retaining the compression function through the sleeve mechanism that applies force directly to the bone fragments without external protrusion
Solution Approach 2:
The sleeve acts as an intermediary component between the screw threads and the bone fragments, transferring the compressive force generated by the distal threads through the sleeve to the bone surface, eliminating the need for a protruding screw head
2Object-affected harmful factors
If headless screws are used to avoid tissue damage, then tissue damage is reduced, but it becomes difficult to maintain the appropriate amount of compression during reduction
Solution Approach 1:
The screw is segmented into distinct functional zones: distal threads for generating compression, a non-threaded portion for engagement with the sleeve, and proximal threads for final bone engagement. This segmentation allows independent control of compression generation and maintenance
Solution Approach 2:
The sleeve serves as a mediator that maintains compression during the transition from distal thread engagement to proximal thread engagement, ensuring continuous compressive force without requiring a protruding head
3Strength
If proximal threads are allowed to engage with the bone immediately, then fixation is achieved, but compression is lost as the threads engage the bone surface
Solution Approach 1:
The threading is segmented into distal and proximal portions with a non-threaded section in between, allowing sequential engagement where distal threads establish compression first, then proximal threads provide fixation without compromising the pre-established compressive force
Solution Approach 2:
The distal threads perform the preliminary action of generating compression force before the proximal threads engage with the bone, ensuring that compression is established and maintained throughout the fixation process
Data Source
AI summary
Systems, tools, and screws for reducing a bone fracture are disclosed. In embodiments, the system comprises: a screw, a driver, a sleeve comprising a longitudinal bore configured to enable insertion of the driver through the sleeve, a locking mechanism configurable into a first state that locks the sleeve to the driver and a second state that unlocks the sleeve from the driver, and a retaining sleeve coupled to a first end of the driver and configured to couple to the screw. In the first state, the sleeve applies a compressive force while distal threads of the screw are driven into the bone while retaining proximal threads of the screw in the sleeve. After a desired compression is achieved, the locking mechanism is configured to the second state, allowing the proximal threads of the screw to be driven into the bone while maintaining application of the compressive force to the bone.