Cannulated Nail Extractor Wire Engagement Mechanism
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Solution Overview
Problem
Conventional tools are ineffective in extracting tightly wedged or broken cannulated nails from bones, as they struggle to grasp or remove the lower portions of broken nails or those wedged in place during the bone healing process.
Innovation Solution
A cannulated nail extractor with an engagement wire and positioning wire system, where the engagement wire has an enlarged distal end to engage with the cannulated nail and a positioning wire to guide it, allowing for the application of extraction force to remove the nail from the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional forceps or elongated clamping instruments are used to grasp and remove the cannulated nail, then the upper portion of a broken cannulated nail can be removed, but the instruments are ineffective in extracting tightly wedged cannulated nails or the lower portions of broken cannulated nails
Solution Approach 1:
The extraction system is divided into separate functional components: a positioning wire to navigate and position the engagement wire, and an engagement wire with an enlarged distal end to actually engage and extract the cannulated nail. This segmentation allows each component to be optimized for its specific function, with the engagement wire's enlarged end providing reliable engagement with the nail while the positioning wire ensures proper placement without risking damage to surrounding tissue.
Solution Approach 2:
The engagement wire is inserted through the cannulated nail with its enlarged distal end positioned within the nail's medullary cavity. The positioning wire is then inserted through the same nail, and the distal end of the positioning wire engages with and pulls the engagement wire through the nail. This nested arrangement allows the engagement wire to be properly positioned and secured within the nail structure, enabling effective extraction of tightly wedged nails that conventional external forceps cannot access.
2Reliability
If the engagement wire has an enlarged distal end to engage with the cannulated nail, then extraction effectiveness is improved, but the wire becomes more complex in structure
Solution Approach 1:
The engagement wire has a constant diameter along most of its length for easy insertion and minimal resistance, but features a localized enlarged distal end that provides the necessary engagement surface with the cannulated nail. This local quality change allows the wire to maintain simplicity in its overall structure while providing reliable engagement capability where needed, avoiding the complexity of uniformly thick or variably shaped wires.
3Productivity
If the positioning wire and engagement wire are inserted through the cannulated nail, then the nail can be extracted, but the wires must be precisely positioned to avoid damaging surrounding tissue
Solution Approach 1:
The positioning wire serves as an intermediary tool that is inserted first to establish a safe pathway through the cannulated nail. The engagement wire is then inserted through the same pathway, with its distal end engaging the nail for extraction. This intermediary approach allows both wires to be properly positioned without directly engaging with the nail initially, reducing the risk of damaging surrounding tissue while maintaining extraction efficiency.
Data Source
AI summary
A cannulated nail extractor including an extractor having a proximal end for connecting to an extraction device, a distal end opposite the proximal end, and a connector extending from the distal end. The cannulated nail extractor further includes an engagement wire having an enlarged proximal end configured to engage the extractor and an enlarged distal end configured to engage a distal end of the cannulated nail. The cannulated nail extractor further includes a positioning wire for insertion into the cannulated nail for urging the enlarged distal end of the engagement wire into engagement with the distal end of the cannulated nail, whereby exerting an extraction force on the extractor produces extraction force by engagement of the enlarged distal end of the engagement wire on the distally facing end of the cannulated nail.