Tissue Sampling Cannula With Slit for Endoscope
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Solution Overview
Problem
Existing tissue sampling devices face challenges in sampling sufficient body tissue for pathological definitive diagnosis due to the thin diameter of the cannula, which limits the amount of tissue that can be collected and requires complex operations to obtain enough tissue for diagnosis.
Innovation Solution
A tissue sampling device with a cannula featuring a slit extending from the distal end to the proximal end, allowing for a larger diameter when protruded and enabling the collection of a greater amount of tissue through a gap formed by the slit, along with a rotary operation unit to facilitate sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the diameter of the cannula is increased to sample more body tissue, then the amount of sampled tissue is improved, but the cannula cannot be introduced through the treatment tool insertion channel of the endoscope
Solution Approach 1:
The cannula is designed with a dynamic structure that allows it to change its effective sampling diameter. When the cutting edge penetrates the tissue, the cannula expands or opens to a larger diameter to capture more tissue samples, while maintaining a smaller profile for introduction through the endoscope channel. This dynamic transformation resolves the contradiction between needing large diameter for tissue sampling and small diameter for channel passage.
Solution Approach 2:
The cannula with larger effective sampling diameter is nested within or constrained during the introduction phase, allowing it to pass through the limited diameter insertion channel. Once positioned, the cannula deploys or expands to its full sampling capacity. This nesting approach allows the system to accommodate both size requirements at different operational stages.
2Quantity of substance
If the diameter of the cannula is increased to sample more body tissue, then the amount of sampled tissue is improved, but the rigidity of the cannula increases making operation difficult
Solution Approach 1:
The cannula employs dynamic rigidity characteristics - remaining flexible during introduction and manipulation through the endoscope channel, then becoming rigid or stable when deployed for tissue sampling. This dynamic property adjustment allows the cannula to satisfy both ease of operation during insertion and structural stability during the sampling function.
Solution Approach 2:
The cannula may be divided into segments or sections with different mechanical properties. The proximal portion remains flexible for easy manipulation and introduction, while the distal sampling portion provides structural stability and rigidity when deployed. This segmentation allows different parts of the cannula to optimize for their specific functional requirements.
3Ease of operation
If a thin cannula is used to pass through the endoscope channel, then the ease of operation for introduction is improved, but the amount of sampled tissue is insufficient
Solution Approach 1:
The cannula transforms from a thin, flexible introduction configuration to a larger, stable sampling configuration. During introduction, the cannula maintains a thin profile for ease of operation. Upon deployment, it expands or opens to provide a larger sampling aperture, thereby capturing sufficient tissue volume without compromising the ease of initial introduction.
Solution Approach 2:
The cannula utilizes dimensional transformation, changing its effective sampling dimension from a small circular aperture to a larger opening through expansion, rotation, or structural reconfiguration. This dimensional change allows the cannula to pass through the limited channel diameter while still providing sufficient sampling area when deployed.
Data Source
AI summary
A tissue sampling device including a flexible sheath, a cannula inserted into the sheath so as to be movable back and forth and punctured into body tissue, and an operation unit provided on a proximal end side of the sheath to move the cannula back and forth, wherein the cannula has a distal end part including a slit extending from a distal end opening toward a proximal end side.