Full-Core Biopsy Cannula With Excising Finger Sample Severing
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Solution Overview
Problem
Existing core biopsy devices face challenges in obtaining full core samples without damaging the sample or causing excessive tissue damage, particularly with devices that rely on relative movement between cannulas or require additional structures like raceways, which can lead to incomplete samples or increased invasiveness.
Innovation Solution
A biopsy device with a spoon cannula and coring cannula assembly that advances without rotation, using an excising finger to sever the sample from the tissue mass, ensuring a complete specimen core is obtained with minimal tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a full core biopsy device uses a coring cannula with a non-notched stylet to obtain a full core sample, then the sample size is improved, but the sample may be pulled out of the coring cannula upon withdrawal because the end of the sample is not positively severed from the tissue mass
Solution Approach 1:
The biopsy device is divided into multiple functional components: a coring cannula for obtaining the full core sample, a separate severing finger for cutting the sample from the tissue mass, and a retention mechanism using the stylet and cannula assembly. This segmentation allows each component to perform its specific function optimally without compromising the others.
Solution Approach 2:
The stylet acts as an intermediary element that plugs the end of the coring cannula during insertion and remains in place during the severing process. It mediates between the coring cannula and the tissue, providing structural support and enabling the severing finger to cut the sample without compromising the retention mechanism.
2Reliability
If practitioners pivot the biopsy device to sever the attached portion of the sample, then sample retention is improved, but tissue damage increases
Solution Approach 1:
The severing finger is extracted as a separate, dedicated component that performs the cutting function. This allows the coring cannula to maintain its original simple structure without requiring complex pivoting mechanisms, thereby reducing tissue damage while ensuring complete sample separation.
Solution Approach 2:
The severing finger is advanced through the coring cannula in a controlled, preliminary action before withdrawal. This pre-severing of the sample from the tissue mass ensures that the sample is completely separated and retained within the coring cannula without requiring subsequent pivoting or manipulation that would cause tissue damage.
3Reliability
If a notched inner stylet and outer severing cannula combination is used, then sample retention is improved, but the sample size is reduced producing a partial core biopsy
Solution Approach 1:
The invention merges the functions of the coring cannula and severing mechanism into a unified assembly where the coring cannula obtains the full core sample and the integrated severing finger completes the separation. This combination allows the sample to be both fully captured and completely severed from the tissue mass, resolving the trade-off between sample size and retention.
Data Source
AI summary
A full core biopsy device includes a needle assembly having stylet, spoon, and at least one coring cannula. A window is located in at least one of the spoon and coring cannula. An excising finger is configured to prolapse through the window into a lumen of the inner spoon or cannula to sever a tissue sample upon translation or axial advancement of the excising finger.