Bone Screw Extraction Shaft With Tissue-Clearing Tip Channels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tissue ingrowth over the driving recess of bone screws makes it difficult for conventional screwdrivers to engage and remove the screws from the bone.
Innovation Solution
A bone screw extraction device with a distal tip featuring a plurality of fingers and channels that facilitate the removal of in-grown tissue, allowing the distal tip to be seated within the driving recess and rotated to extract the screw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional screwdriver is used to remove the bone screw, then the driving recess must be accessible, but tissue ingrowth blocks engagement making removal difficult
Solution Approach 1:
The extraction device includes a tissue-receiving cavity that extracts and contains the ingrown tissue during insertion. This removes the harmful tissue blockage from the engagement path, allowing the fingers to properly engage the driving recess notches without obstruction
Solution Approach 2:
The distal tip is segmented into multiple fingers with grooves between them, allowing the structure to interact with the driving recess notches in a segmented manner. This segmentation enables each finger to engage with corresponding notches while the grooves allow tissue to be channeled out, resolving the contradiction between needing solid engagement and managing tissue obstruction
2Productivity
If the extraction device engages the driving recess, then screw removal is enabled, but force must be applied to overcome tissue ingrowth
Solution Approach 1:
The channels between the fingers convert the harmful tissue ingrowth into a beneficial feature by channeling it outward during insertion. The tissue that previously blocked engagement is now directed through the channels and grooves, clearing the path for finger engagement with the driving recess notches and reducing the force needed for subsequent rotation
Solution Approach 2:
The fingers act as intermediaries between the extraction device shaft and the driving recess. They transmit rotational force efficiently while the grooves and channels mediate the tissue management function, allowing force application without the resistance of compressed tissue
3Reliability
If the distal tip is inserted into the driving recess, then engagement is achieved, but tissue must be displaced
Solution Approach 1:
The tissue-receiving cavity and channels extract tissue from the driving recess area during insertion, directing it outward through the channels rather than compressing or disrupting surrounding tissue. This reduces tissue disturbance while ensuring reliable engagement of the fingers with the driving recess notches
Solution Approach 2:
The extraction device exhibits local quality differentiation: the fingers provide rigid engagement with the driving recess for reliable force transmission, while the grooves and channels provide compliant pathways for tissue flow. This local differentiation allows reliable engagement without requiring uniform tissue displacement throughout the entire device structure
Data Source
AI summary
A bone screw extraction device includes a shaft extending longitudinally from a proximal end to a distal tip, a distal portion of the shaft including a tissue-receiving cavity extending proximally thereinto from the distal tip, the distal tip including a plurality of fingers configured to be received within a driving recess of a bone screw and a plurality of channels extending longitudinally along an exterior surface of the distal portion, each of the plurality of channels extending between adjacent ones of the plurality of fingers.