Endoscopic Basket Wire Geometry for Stepped Gallstone Retrieval
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Solution Overview
Problem
Conventional basket-type gripping forceps struggle to effectively retrieve gallstones trapped in stepped portions between the bile duct and duodenal papilla due to structural limitations, and balloon catheters fail to dislodge such stones without causing them to adhere to the duct wall.
Innovation Solution
An endoscope treatment tool featuring a sheath with a basket section composed of elastic wires, including maximum outer, first, and second maximum sections, designed to expand and contract, allowing it to engage and retrieve gallstones from stepped portions by tilting and expanding to fit the bile duct's geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional basket section with uniform wire structure is used, then the device is simple in structure, but it cannot effectively catch gallstones trapped in stepped portions of the bile duct
Solution Approach 1:
The elastic wire is designed with non-uniform cross-sectional area, creating maximum outer diameter sections with larger area and first/second maximum sections with smaller area. This local variation in wire properties allows the basket section to have enhanced catching capability at specific locations while maintaining overall structural simplicity.
Solution Approach 2:
The maximum outer diameter section of the elastic wire forms a curved, rounded structure that protrudes from the basket section. This spherical/rounded geometry enables the basket to effectively engage with gallstones trapped in stepped portions of the bile duct, improving the reliability of stone capture.
2Ease of operation
If a balloon catheter is used to press the gallstone, then the device is simple, but it fails to eject the gallstone from the stepped portion
Solution Approach 1:
The basket section incorporates elastic wires with varying cross-sectional areas, creating localized maximum outer diameter sections that protrude beyond the basket. This local structural enhancement provides effective engagement with gallstones in stepped portions, enabling reliable ejection without complex mechanisms.
Solution Approach 2:
The elastic wires are designed to be flexible and deformable, allowing the basket section to dynamically adapt to the stepped geometry of the bile duct. The wires can bend and expand to reach gallstones in difficult-to-access locations, improving operational effectiveness while maintaining simplicity.
3Adaptability or versatility
If the basket section has a uniform wire structure, then the manufacturing is simple, but it cannot adapt to the stepped geometry of the bile duct
Solution Approach 1:
The elastic wire is manufactured with intentionally non-uniform cross-sectional area, creating maximum outer diameter sections at specific locations. This local variation in wire geometry enables the basket section to adapt to stepped portions of the bile duct while maintaining relatively simple manufacturing processes.
Solution Approach 2:
The cross-sectional area parameter of the elastic wire is varied along its length, creating sections with different diameters. This parameter change allows the basket section to adapt to different geometries within the bile duct, particularly stepped portions, without requiring complex multi-component structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The tool reliably catches and ejects gallstones from oblique steps between the bile duct and duodenal papilla, ensuring secure capture and extraction without dropping the stone during the process.
Implementation Method 1
one of the elastic wires has: a maximum outer diameter section at which an outer diameter of the basket section is largest
Data Source
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AI summary
In order to more reliably catch and eject even a gallstone trapped in a stepped portion obliquely formed at a boundary between the bile duct and the duodenal papilla, an endoscope treatment tool (1) according to the present invention includes: a sheath (2) having a lumen extending along the longitudinal axis; a basket section (4) that protrudes from the lumen and that has at least one elastic wire (4a); and an operating wire (5) for advancing/retracting the basket section in the longitudinal direction of the sheath, wherein the elastic wire has: a maximum outer diameter section where the outer diameter of the basket section is largest between the distal end and the proximal end of the elastic wire; a first maximum section that, in a lateral view from a direction orthogonal to a normal from the maximum outer diameter section to the central axis of the basket section, is largest on the opposite side of the central axis from the maximum outer diameter section between the maximum outer diameter section and the proximal end of the elastic wire; and a second maximum section that is largest at a position away from the normal between the maximum outer diameter section and the first maximum section, and in the front view of the basket, the first maximum section is located on the opposite side of a straight line, which is orthogonal to the normal at the central axis, from the maximum outer diameter section side.