Non-Circular Polypectomy Snare Structural Stability
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Solution Overview
Problem
Current polypectomy devices face issues with snare buckling, bending, and crossing of legs during polyp removal, which can lead to inefficiencies and complications in the procedure.
Innovation Solution
A polypectomy device with a snare designed to have a non-circular cross-sectional shape, featuring a monofilament wire with varying cross-sectional areas and traction members, which reduces buckling and bending, and includes a method for manufacturing such a device with specific regions and shapes to maintain stability and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional circular cross-sectional snare is used, then the snare is easy to manufacture, but the snare experiences buckling, bending, and crossing of legs during polyp removal
Solution Approach 1:
The snare is designed with a non-circular (e.g., D-shaped or oval) cross-sectional shape instead of the conventional circular shape. This asymmetric geometry provides inherent structural rigidity that prevents buckling and bending during polyp removal while maintaining ease of manufacture through standard wire forming processes
Solution Approach 2:
The snare features varying cross-sectional areas along its length, with thicker regions at critical stress points (such as the proximal end and loop formation areas) and thinner regions in the distal portion. This localized variation in structural properties optimizes strength where needed while reducing overall complexity and material usage
2Reliability
If the snare has a non-circular cross-sectional shape, then buckling and bending are minimized, but manufacturing precision requirements increase
Solution Approach 1:
The non-circular cross-sectional shape (such as D-shaped or oval) is designed with simple geometric forms that can be accurately produced using standard wire forming and bending processes, avoiding complex asymmetric geometries that would require high-precision manufacturing while still providing sufficient structural stability
Solution Approach 2:
The snare design incorporates specific dimensional parameters for the non-circular cross-section (such as width-to-height ratios and curvature radii) that are optimized to provide structural stability while remaining within the manufacturing capabilities of standard medical device fabrication processes
3Reliability
If the snare includes varying cross-sectional areas, then structural stability is improved, but device complexity increases
Solution Approach 1:
The snare features varying cross-sectional areas at specific locations along its length, with thicker sections at the proximal end and loop formation areas for enhanced strength, and gradually thinner sections toward the distal end. This localized variation provides structural stability where needed while maintaining overall design simplicity
Solution Approach 2:
The snare is designed as a monofilament structure with continuous varying cross-sectional area rather than discrete segmented components, which simplifies the overall device complexity while still achieving the desired structural stability through gradual geometric transitions
Data Source
AI summary
Polypectomy devices and methods for making and using polypectomy devices are disclosed. An example polypectomy device may include an elongate sheath having a proximal end region and a distal end region. A shaft may be slidably disposed within the sheath. A handle may be coupled to the proximal end region of the sheath. The handle may be designed to axially shift the shaft relative to the sheath. A snare may be coupled to the shaft. The snare may include a first region, a traction region, and a distal tip region. The first region may have a non-circular cross-sectional shape. The traction region may include a plurality of traction members. At a position between two adjacent traction members the snare may have a reduced cross-sectional area relative to the first region. The distal tip region may have a circular cross-sectional shape.