Rotating Cannula Biopsy Device for Full-Core Tissue Sampling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing biopsy devices often fail to obtain a full core of tissue due to inaccuracies in inserting the device, leading to overshot or undershot of the target tissue, and may crush or not retrieve enough tissue, especially when encountering tissues of varying densities, resulting in samples that are not representative for analysis.
Innovation Solution
A biopsy device comprising two tubular cannulas with slits that can be rotated between open and closed positions, allowing for precise insertion and cutting of tissue samples, ensuring a full 360-degree sample is obtained by aligning or misaligning the slits to control tissue entry and cutting, with a handle mechanism for easy operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a forward-thrusting cannula is used to move through tissue quickly, then the cutting speed is improved, but the tissue may be pressed forward rather than sheared cleanly, resulting in crushing or insufficient sample retrieval
Solution Approach 1:
The cannula system transitions from a static forward-thrusting mechanism to a dynamic rotating cutting mechanism. The inner cannula rotates relative to the outer cannula to shear tissue, converting linear motion into rotational cutting motion for cleaner cuts without tissue crushing
Solution Approach 2:
The single cannula is segmented into two separate cannulas (inner and outer), each with distinct functions. The outer cannula provides structural support and initial tissue penetration, while the inner cannula performs the actual cutting through rotation, separating the penetration and cutting functions
2Speed
If the distal end of the cannula shoots forward beyond the tissue of interest, then the insertion speed is improved, but the sampling accuracy deteriorates, resulting in overshot or undershot of the target tissue
Solution Approach 1:
The slits in the outer and inner cannulas are pre-aligned to create an open passage before tissue sampling begins. This preliminary configuration ensures that when the cannula reaches the target tissue, the cutting edges are already positioned correctly to capture the full 360-degree sample without overshooting or undershooting
Solution Approach 2:
The inner cannula is nested within the outer cannula, with both having slits that align to form a complete circular opening. This nested structure allows precise control of the cutting path and ensures the entire circumference of the target tissue is sampled accurately
3Ease of operation
If the slits in the cannulas are kept open during insertion, then the tissue entry is facilitated, but tissue may enter the lumen prematurely, resulting in sample contamination or loss
Solution Approach 1:
The slit configuration transitions dynamically from an open state during insertion to a closed state during sampling and retrieval. The slits are aligned and open to facilitate smooth tissue entry, then rotated out of alignment to close the passage and secure the tissue sample within the inner cannula lumen
Solution Approach 2:
The slit alignment follows a periodic pattern: open during insertion phase to allow tissue entry, then closed during sampling and retrieval phases to maintain sample integrity. This periodic opening and closing of the passage ensures both ease of operation and sample reliability
Data Source
AI summary
Among other things, there are disclosed embodiments of a biopsy device using relative rotational motion to obtain a full-core biopsy sample. Inner and outer tubular members are provided connected to a handle. Each member includes a slit, and the members are rotatable with respect to each other. The device is inserted into a patient to a sampling site, and with the slits co-oriented, is extended into the sampling site. Tissue enters the tubular members through the slits, and one or both members are rotated to cut off and enclose tissue within the inner tubular member.