Twisted Loop Snare Mechanism for Secure Vascular Object Retrieval
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Solution Overview
Problem
Conventional retrieval devices for loose objects in the vascular system, such as hooks and jaws, face challenges in securely engaging and removing objects without causing tissue damage, especially in tight spaces and when objects are at odd angles, and existing snare devices struggle with flexibility and ease of deployment.
Innovation Solution
A snare device featuring a twisted loop configuration with two loops connected by a twisting area, deployable from a catheter, and a locking wire for secure engagement and retrieval, allowing for flexible movement through tight spaces and adjustable angles for optimal capture and cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hook-shaped tool is used to engage and retrieve loose objects, then the object can be captured and pulled from the vascular system, but the hook can become dislodged when reverse translation occurs and may damage surrounding tissue
Solution Approach 1:
Instead of using a hook that protrudes to engage objects, the patent uses a loop configuration where the engagement surface is on the interior of the loop. The loop is collapsed into the catheter and deployed outward to capture objects, reversing the conventional hook approach. This inversion prevents the engagement element from becoming dislodged during retraction and eliminates the need for sharp protruding elements that could damage tissue.
Solution Approach 2:
The snare device employs a flexible loop structure made of compliant material that can be collapsed into a catheter and deployed outward. The loop's flexibility allows it to conform to objects of various shapes and sizes while maintaining a safe profile during retrieval. The thin, flexible nature of the loop enables it to navigate tight vascular spaces without causing tissue injury, unlike rigid hooks or jaws.
2Reliability
If jaws or forceps are used to clamp onto loose objects, then secure engagement is achieved, but the device size becomes too large for many vessels and tissue damage occurs
Solution Approach 1:
The snare device divides the engagement function into two segments: the loop structure that provides the grasping action and the catheter that provides the delivery and retrieval pathway. The loop can be collapsed into a small profile within the catheter for easy navigation through vessels, then deployed to create a functional engagement surface. This segmentation allows the device to be both small during transit and functional during use.
Solution Approach 2:
The loop is designed to nest within the catheter during the delivery phase, with the loop collapsed into a compact configuration that fits within the catheter's lumen. Once at the target location, the loop is deployed outward from the catheter tip to engage the loose object. This nesting approach allows the device to pass through tight vascular spaces without requiring large external structures.
3Device complexity
If a single loop snare is used, then the device is simple in structure, but it lacks flexibility and ease of deployment in tight spaces
Solution Approach 1:
The snare device is segmented into multiple loops connected in series, with each loop capable of independent deployment and engagement. This segmentation provides flexibility in navigating tight vascular spaces, as the loops can be deployed sequentially to adapt to the anatomy of the vessel and the location of the loose object. The modular loop structure maintains relative simplicity while significantly improving operational flexibility.
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 enables secure capture and retrieval of objects with minimal tissue injury, facilitating removal through tight vascular spaces and allowing for precise cutting without electrical current, reducing the risk of damage and improving procedural efficiency.
Implementation Method 1
a snare device for capturing an object and/or for cutting a tissue comprising at least one twisted loop of memory shaped material
Data Source
Figure 1A~1C
Figure 2A~2D
Figure 2E~2H
AI summary
In a snare device (10) for capturing an object (22) and/or for cutting a tissue (24) comprising at least one twisted loop of memory shaped material, the loop being housed in and movable relative to a hollow member, especially a catheter (26), to be deployed and retracted into the hollow member (26), a locking wire (18) is provided for being translated through the at least one loop (12) to capture an object (22) between part of the loop (12,14) and the locking wire (18) extending through the loop (12) and/or for puncturing the tissue (24) and/or for cutting the tissue by the loop (12) as combined with the locking wire (18) the locking wire (18) piercing the tissue (24) at an aperture (30) distant from an aperture (28) at least part of the loop (12) extends through the locking wire (18) being translated through the loop (12) and engaging with the same and retracting the loop (12) into the hollow member (26) such that the tissue (24) is cut between both of the apertures (28,30).