Biopsy Needle Inner Stylet Segmentation for Symmetrical Tissue Sampling
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Solution Overview
Problem
Traditional notched-stylet biopsy needles often obtain asymmetrically truncated tissue samples, are prone to bending, and require multiple samples or longer throw lengths, which can lead to sample inadequacy and discomfort for patients.
Innovation Solution
A biopsy needle design featuring an inner stylet with spaced apart elongated members or struts defining a sample-containment space with radially-opposed openings, enhancing sample symmetry and rigidity, allowing tissue to prolapse from multiple directions and reducing the risk of deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the throw length is increased to obtain more tissue, then the tissue sample volume increases, but the stylet rigidity decreases and bending/deflection increases
Solution Approach 1:
The stylet is segmented into a proximal portion and a distal portion, with the distal portion featuring a notched tip that is separated from the main body. This segmentation allows the notched distal portion to be thinner for better tissue access while the proximal portion maintains sufficient thickness for rigidity, resolving the contradiction between sample volume and stylet strength.
2Quantity of substance
If the notch depth is increased to capture more tissue, then the tissue sample volume increases, but the stylet becomes more prone to bending and deflection
Solution Approach 1:
The notched portion is extracted as a separate distal segment from the main stylet body. This allows the notch to be optimized for deep tissue capture while the main body retains full structural integrity, eliminating the trade-off between notch depth and stylet stability.
3Quantity of substance
If the overall size of the stylet and cannula is increased to accommodate deeper notches, then the tissue sample volume increases, but patient discomfort and insertion difficulty increase
Solution Approach 1:
By segmenting the stylet into proximal and distal portions with different dimensions, the design allows the distal notched portion to be compact for patient comfort while the overall device maintains the capability for deep tissue sampling through the notched geometry rather than increased size.
4Quantity of substance
If more of the stylet is removed to form a deeper notch, then the tissue sample volume increases, but the stylet rigidity decreases
Solution Approach 1:
The notched portion is extracted as a separate distal segment, allowing aggressive notch geometry for deep tissue capture without compromising the main stylet body's structural integrity. The removed material is confined to the distal portion only, preserving proximal rigidity.
Data Source
AI summary
Among other things, there is disclosed a biopsy needle having a cutting cannula axially slidable over an inner stylet. The inner stylet has a proximal portion connected to a distal portion that includes first and second spaced-apart struts. The distal portion has a tissue penetrating tip and the stylet defines a sample-containment space between the struts having first and second radially opposed lateral openings thereto. The sample-containment space of the stylet readily accepts tissue through either of the lateral openings such that a near full core of tissue can be sampled.