Snare Loop Geometry for Polyp Capture
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Solution Overview
Problem
Existing snare loop treatment instruments struggle to efficiently capture polyps of varying sizes without excessive operation resistance or tissue entrapment, as the loop's geometry and angle configuration lead to rapid shrinkage and incomplete capture of small polyps or excessive tissue inclusion with large polyps.
Innovation Solution
A treatment instrument with a loop portion having specific length and angle configurations, where the second region is longer than the first and third regions, and the angle between these regions is smaller than the distal end angle, allowing for adjustable loop size and minimized operation resistance, enabling effective capture of polyps of different sizes while preventing normal tissue entrapment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the snare loop has a conventional geometry with equal or short second region length, then the loop can be easily pulled into the sheath, but the loop shrinks rapidly and cannot completely capture small polyps
Solution Approach 1:
The patent changes the geometric parameters of the snare loop, specifically making the second region length L2 longer than the first region length L1 and third region length L3. This parameter modification allows the loop to maintain a larger size when pulled into the sheath, preventing rapid shrinkage and enabling complete capture of small polyps while still allowing smooth retraction.
2Adaptability or versatility
If the snare loop has a larger size to capture big polyps, then big polyps can be captured, but small polyps cannot be completely captured due to rapid shrinkage
Solution Approach 1:
The patent applies local quality by creating different region lengths within the loop structure. The second region is specifically made longer than the first and third regions, creating a localized structural difference that controls the loop's shrinkage behavior. This allows the loop to adapt to different polyp sizes while maintaining precise control over its size transformation characteristics.
3Area of stationary object
If the angle between the first region and second region is large, then the loop maintains a larger opening for big polyps, but the loop shrinks too rapidly when pulled into the sheath
Solution Approach 1:
The patent introduces asymmetry in the loop geometry by making the angle between the first region and second region smaller than other angles in the loop structure. This asymmetric angle configuration, combined with the longer second region, creates a controlled shrinkage profile that maintains loop opening area for capturing polyps while extending the duration that the loop maintains its size during retraction into the sheath.
Data Source
AI summary
A treatment instrument is that a maximum dimension of the loop portion in a direction orthogonal to the longitudinal axis in a state where half of a total length of the loop portion in a direction of the longitudinal axis of the loop portion is pulled into the sheath is 40% to 60% of a maximum dimension of the loop portion in the orthogonal direction in a state where the whole loop portion protrudes from a distal end of the sheath.