Biopsy Device with Differential Pull Wire Transport
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Solution Overview
Problem
Existing biopsy devices for obtaining multiple tissue samples through endoscopic or laparoscopic methods face challenges such as inadequate sample transport mechanisms, size limitations, and damage to samples during retrieval, leading to inefficient sampling and poor sample quality.
Innovation Solution
A biopsy device with a tissue cutting assembly featuring differentially pullable clamshell cups and a sample transport assembly that includes a sample transport unit and storage assembly, utilizing a pair of differential pull wires for both rotational and linear movement to collect and store multiple samples within a tubular structure without the need for frequent device retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional biopsy forceps are used with small size and separate retrieval for each sample, then device simplicity is maintained, but sampling time increases and sampling error increases
Solution Approach 1:
The device divides the sampling process into distinct functional segments: cutting jaws for obtaining samples, a transport mechanism for moving samples, and a storage chamber for retaining multiple samples. This segmentation allows the cutting and storage functions to be separated, enabling multiple samples to be collected in one insertion without repeated forceps retrieval.
Solution Approach 2:
The sample transport mechanism is nested within the biopsy forceps structure, with the transport channel and storage chamber integrated into the forceps shaft. This nested arrangement allows the transport and storage functions to be contained within the existing forceps footprint, enabling multiple sample collection without increasing the overall device size or requiring separate retrieval operations.
2Quantity of substance
If the sample storage space diameter is made narrower than the cutting jaws in closed position, then sample storage capacity is increased, but transfer of procured samples into storage space is impeded
Solution Approach 1:
The device employs dynamic dimensional changes in the sample transport channel. The channel has a larger diameter portion for receiving cut samples and a narrower portion for storage, with a transitional section that facilitates sample movement. This dynamic geometry allows easy transfer from the cutting zone to the storage zone while maintaining high storage capacity.
Solution Approach 2:
A sample transport mechanism acts as an intermediary between the cutting jaws and the storage chamber. This transport mechanism includes a transport channel with optimized geometry and potentially a pushing or guiding element that facilitates the movement of samples from the wider cutting zone through the transitional section into the narrow storage space, eliminating the impeding effect of the narrow diameter.
3Ease of operation
If rotational torque is applied to transfer viscous samples, then sample transport is achieved, but significant rotational torque is required which may damage samples or require complex mechanisms
Solution Approach 1:
The device replaces rotational mechanical action with linear axial motion for sample transport. Instead of using a spiral wire that requires rotational torque, the invention employs a linear transport mechanism where samples are moved axially through the forceps shaft. This substitution eliminates the need for significant rotational torque, reducing the risk of sample damage while maintaining transport capability.
Solution Approach 2:
The device changes the motion parameter from rotational to linear. By transforming the sample transport mechanism from a rotational spiral system to a linear axial movement system, the force requirements are fundamentally changed. Linear motion requires significantly less force than rotational torque, especially for viscous samples, and can be achieved through simple axial pushing or guiding mechanisms rather than complex rotational systems.
4Device complexity
If dual action mechanism with rotary motion is used to cut and transfer samples, then cutting and transport functions are combined, but premature transition of rotary biting force to axial motion causes slippery bite and limited axial motion is inadequate for pushing samples back
Solution Approach 1:
The device separates the cutting function from the transport function into distinct mechanical systems. The cutting jaws perform the cutting action independently with dedicated rotary or axial biting motion, while the transport mechanism independently handles sample movement through the axial channel. This segmentation prevents interference between cutting and transport operations, ensuring reliable cutting without premature transition to axial motion.
Solution Approach 2:
The cutting action is completed fully before the transport mechanism engages. The cutting jaws maintain their cutting position and complete the cutting motion to secure a reliable bite on the tissue, then only after cutting is finalized does the transport mechanism begin to move the sample axially. This preliminary completion of the cutting action prevents slippery bites and ensures adequate cutting effectiveness.
Data Source
AI summary
Provided herein are a device and methods to obtain multiple serial samples from biologic tissues located in a tubular or cavitary space of a body. The device has a proximal and distal end, with a linear shaft connecting both ends. The distal end of the device comprises a tissue cutting assembly, a sample transport assembly and a sample storage assembly. The sample transport assembly comprises a slidable sample transport unit, a semi-cylindrical tubular sample chamber with a pair of axially linear rails located on both sides of said chamber and a system of differential pull wires. The sample transport unit slides on the rails of the sample chamber, providing longitudinally axial movement of the cup connected to said sample transport unit. The sample storage assembly comprises said sample chamber, a reversibly detachable sample catcher inserted in said sample chamber, a tubular sample housing and an expandable tubular sample housing.