Helical Tissue Sampling Instrument with Variable Radius Zone
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Solution Overview
Problem
Existing tissue sampling instruments struggle to effectively extract samples from tissues with unifrontal and bifrontal fibers due to insufficient cutting force, fiber accumulation impeding the cutting movement, and potential tissue damage from tapered designs.
Innovation Solution
A tissue receiving element with a spiral or helix structure that has a zone with a smaller distance from the outer surface to the central axis, extending over at least one winding, providing space for fibers and preventing tissue damage, allowing for effective sample extraction without compromising cutting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spiral or helical tissue receiving element is made with uniform thickness throughout its length, then the structural strength is maintained, but the cannula cannot cut through fibers effectively and fibers accumulate in the limited space
Solution Approach 1:
The tissue receiving element has different thicknesses at different locations: thicker at the proximal end for structural strength and thinner at the distal end for easier fiber passage and cutting, allowing each part to have the quality needed for its specific function
2Ease of operation
If the distal end of the spiral is narrowed to enable easier penetration into tissue, then insertion is facilitated, but the tissue sample becomes damaged and cannot be taken undamaged
Solution Approach 1:
The spiral has a tapered distal end section with smaller radius for easier tissue penetration, while the proximal section maintains larger radius to preserve structural integrity and provide space for undamaged sample collection, allowing different regions to have different geometric properties suited to their specific operational requirements
3Force
If the spiral tissue receiving element exerts strong pulling force to tear off bifrontal fibers, then sample extraction is improved, but the cannula movement is impeded by accumulated fibers
Solution Approach 1:
The spiral geometry provides a third spatial dimension (radial space between windings) for fiber accumulation, allowing fibers to be pushed radially outward during cutting rather than blocking the linear path of the cannula, thus maintaining cutting efficiency while enabling strong pulling force
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Instrument (1) for taking a tissue sample, that comprises a tissue receiving element (3) with a distal end (7) and a proximal end (8) and at least partly consists of a spiral or helix that has an outer surface (11) and which has a central longitudinal axis (X-X'), characterised in that the spiral or helix has at least has one zone where the distance (dd) from the outer surface (11) to the central longitudinal axis (X-X') is smaller than at a more proximally located part of the spiral or helix.