Miniature Biopsy Forceps Jaw Design for Tissue Capture
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Solution Overview
Problem
Current biopsy forceps with small diameters struggle to effectively access and retrieve tissue samples from tortuous and small cross-sectional areas within the body, particularly in the pancreaticobiliary system, due to limited working channel sizes and insufficient cutting or shearing forces.
Innovation Solution
The design of miniature biopsy forceps with specific jaw configurations, including curved edges, teeth patterns, and tissue retention features such as pyramid-shaped spikes and fenestration holes, allows for precise access and improved sample retention, enabling effective tissue capture and retrieval in small anatomical spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If smaller diameter endoscopes are used to reduce trauma and access diverse body lumens, then ease of operation and adaptability improve, but the working channel size decreases which limits the size of biopsy specimens that can be collected
Solution Approach 1:
The biopsy forceps are designed with a nested structure where the jaws can be fully retracted into the handle when not in use, allowing the entire assembly to pass through small working channels. The jaws extend outward only when needed for tissue capture, enabling access through small endoscopes while maintaining adequate specimen size capability.
Solution Approach 2:
The forceps employ a dynamic jaw mechanism that transitions from a closed retracted state during insertion to an open expanded state during tissue capture. This dynamic transformation allows the device to adapt its size - small during passage through the endoscope and large enough to capture adequate tissue samples when deployed.
2Ease of operation
If smaller diameter biopsy forceps are used to fit through small working channels, then ease of operation improves, but the moment arm of the instrument decreases which reduces the cutting and shearing force of the jaws
Solution Approach 1:
The jaws are pre-loaded with resilient material that stores elastic energy during the closing motion. This preliminary action of compressing the resilient material during jaw closure provides an additional force boost that compensates for the reduced moment arm, enabling adequate cutting and shearing force despite the small instrument diameter.
Solution Approach 2:
The jaw construction incorporates composite materials including resilient or elastic material integrated into the jaw structure. This composite design allows the small-diameter forceps to generate sufficient cutting force by utilizing the elastic properties of the resilient material to amplify the mechanical advantage.
3Ease of manufacture
If conventional jaw designs are used in small diameter forceps, then manufacturing simplicity is maintained, but the jaws are not sharp enough due to machining tolerances and tissue is torn rather than cleanly sheared
Solution Approach 1:
The cutting mechanism transitions from relying solely on mechanically sharp edges (which are difficult to maintain in small instruments) to utilizing the elastic deformation of resilient material. This parameter change from rigid sharpness to elastic cutting action allows for easier manufacturing while achieving clean tissue separation.
Solution Approach 2:
The cutting action is partially replaced by elastic deformation of the resilient jaw material. Instead of relying purely on mechanical sharp edges, the resilient material deforms elastically during tissue capture and separation, providing a cutting mechanism that is less sensitive to machining tolerances and produces cleaner cuts.
4Reliability
If the jaws are designed to close completely to capture tissue, then sample retention improves, but the instrument requires sufficient moment arm to generate adequate closing force
Solution Approach 1:
The resilient material in the jaws is pre-compressed during the closing motion, storing elastic energy that is released to enhance the closing force. This preliminary compression action allows the small-diameter forceps to achieve complete jaw closure and secure tissue retention without requiring a large moment arm or complex structural arrangements.
Data Source
Figure 1
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Figure 3A~3C
AI summary
Embodiments of the invention include devices for obtaining tissue including a proximal actuator and a distal assembly having first and second end effectors. The first and second end effectors include the features of at least one element within the inner surface either of the first and second end effectors for aiding in the capture and retention of a targeted tissue sample.