Spring-Wire Snare Stabilization for Endoscopic Tissue Resection
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Solution Overview
Problem
Endoscopic snares used for tissue resection often slip off the tissue due to their flexibility, making precise and efficient resection challenging, especially in difficult anatomical locations, and the working channel of the endoscope cannot accommodate additional devices for assistance.
Innovation Solution
An endoscopic tissue resection device comprising a cap, a snare sheath, and a spring wire, where the snare wire is collapsible and stabilized by a spring wire, allowing for efficient and precise tissue resection by aligning closely with the cap's inner circumference and edge, enabling suction and resection without occupying the endoscope channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the snare wire is made flexible to be retracted into the sheath, then the snare can be grasped and retracted, but the snare frequently slips off the tissue and cannot engage tissue precisely
Solution Approach 1:
The snare wire's physical state is changed by collapsing it from an expanded grasping configuration to a compressed retracted configuration. This parameter change allows the snare to transition between engaging tissue (expanded) and being stored in the sheath (collapsed), resolving the contradiction between flexibility for retraction and stability for engagement.
Solution Approach 2:
The snare wire is designed to be dynamically configurable between expanded and collapsed states rather than being statically fixed. This dynamic capability allows the system to adapt the snare's form factor based on operational needs - expanded for tissue engagement and collapsed for retraction into the sheath.
2Manufacturing precision
If a secondary device is added to aid in tissue resection, then tissue resection precision and efficiency improve, but the device cannot be used because the snare sheath occupies the only channel within the endoscope
Solution Approach 1:
The snare wire is nested within the sheath in a collapsed state, allowing the sheath to occupy the endoscope channel while the snare remains compact. This nesting enables the system to fit within the constrained endoscope channel while still providing the full functionality of the snare when deployed.
Solution Approach 2:
The snare wire transitions from a three-dimensional expanded configuration for tissue engagement to a one-dimensional linear collapsed configuration for retraction. This dimensional transformation allows the snare to be stored within the sheath's limited space while maintaining its full functional form when needed.
3Reliability
If the snare wire is made rigid to engage tissue, then tissue engagement is improved, but the snare cannot be retracted into the sheath
Solution Approach 1:
The snare wire's structural parameter is dynamically changed between rigid (when expanded for engagement) and flexible/compressible (when collapsed for retraction). This parameter transformation allows the snare to exhibit rigid characteristics when needed for tissue engagement and flexible characteristics when needed for retraction into the sheath.
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 device provides reliable, reproducible, and efficient tissue resection, allowing for endoscopic visualization and retrieval of specimens, while freeing the endoscope channel for additional instruments and enhancing suction capacity.
Implementation Method 1
The spring wire is reversibly deflectable from a resting state to a deflected state, the spring wire being in the resting state when the collapsible snare wire is disposed within the cavity of the cap and deflecting to the deflected state when the collapsible snare wire is retracted into the snare sheath.
Data Source
AI summary
An endoscopic tissue resection device configured to be attached at a distal tip of an endoscope is disclosed. The device comprises a cap, a snare sheath, a snare, and a spring wire. The snare comprises a collapsible snare wire configured to be retracted from the cavity of the cap into the snare sheath, the collapsible snare wire reversibly collapsing upon retraction, and to be advanced from the snare sheath into the cavity of the cap, the collapsible snare wire reversibly expanding upon advancement. The spring wire is reversibly deflectable from a resting state to a deflected state. In the resting state the spring wire orients and stabilizes an apex of the collapsible snare wire within the cap such that two opposing wire portions of the collapsible snare wire are positioned in apposition to a distal opening of the cap.