Wire Guide Mandrel Protrusion Prevention
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Solution Overview
Problem
During percutaneous endovascular procedures, the protrusion of a mandrel through the helically wound coil can cause damage to blood vessels or arteries, especially when navigating sharp or tortuous vascular pathways, as the flexible distal end of the coil is manipulated, leading to potential scraping or puncturing.
Innovation Solution
A wire guide design featuring a helically wound coil with a mandrel that terminates before the distal end, accompanied by first and second safety wires with non-convex contact surfaces positioned on opposite sides of the mandrel's distal tip, which are welded to the distal end of the coil, providing additional support and reducing the likelihood of mandrel protrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the mandrel terminates before the distal end of the helically wound coil to allow flexibility, then maneuverability through tortuous pathways is improved, but the risk of mandrel protrusion and vessel damage increases
Solution Approach 1:
The patent applies beforehand cushioning by positioning safety wires with non-convex contact surfaces between the mandrel tip and the helically wound coil. These safety wires act as protective elements that prevent direct contact between the mandrel tip and the coil, cushioning against potential protrusion forces when navigating tortuous pathways. The non-convex contact surfaces are specifically designed to engage the mandrel tip and prevent it from pushing through the coil structure.
Solution Approach 2:
The safety wires serve as intermediary elements between the mandrel and the helically wound coil. Rather than allowing direct interaction between the mandrel tip and the coil (which could cause protrusion), the safety wires mediate this interaction by providing a protective interface. The intermediary safety wires transfer and distribute forces, preventing the mandrel from directly puncturing through the coil while maintaining the necessary flexibility for maneuverability.
2Stability of the object's composition
If safety wires with convex contact surfaces are used to support the mandrel, then mandrel stability is improved, but the risk of vessel damage from mandrel protrusion increases
Solution Approach 1:
The patent applies local quality by specifying that the contact surfaces of the safety wires facing the mandrel tip must have a non-convex shape. This local geometric feature is critical because non-convex surfaces create mechanical interlocking that prevents the mandrel tip from pushing through the safety wire and potentially damaging the vessel. The non-convex contact surfaces provide localized engagement points that stabilize the mandrel while preventing protrusion, unlike convex surfaces which would allow the mandrel to more easily push through.
3Stability of the object's composition
If a single safety wire is used to prevent coil unraveling, then coil integrity is improved, but protection against mandrel protrusion is insufficient
Solution Approach 1:
The patent applies segmentation by using multiple safety wires (at least two) instead of a single safety wire. These safety wires are positioned at different locations around the mandrel, providing distributed protection against mandrel protrusion. The segmented arrangement of multiple safety wires creates redundant protection zones, ensuring that if one safety wire is compromised, others remain to prevent mandrel protrusion and vessel damage.
Solution Approach 2:
The patent applies parameter changes by modifying the contact surface geometry of the safety wires from convex to non-convex shapes. This parameter change in surface geometry fundamentally alters the mechanical interaction between the safety wires and the mandrel tip. The non-convex contact surfaces create mechanical interlocking that prevents the mandrel from pushing through, thereby enhancing the reliability of protection against mandrel protrusion while maintaining coil integrity.
Data Source
AI summary
A wire guide includes a helically wound coil having a proximal end and a distal end. A mandrel is positioned within the helically wound coil and terminates before the distal end of the helically wound coil. First and second safety wires are positioned within the helically wound coil and have proximal ends attached to the mandrel and distal ends attached to the distal end of the helically wound coil. The first and second safety wires are positioned on opposite sides of a distal tip of the mandrel and have contact surfaces facing the distal tip of the mandrel that have a shape other than convex. The interaction between the mandrel tip and the safety wires during a percutaneous vascular procedure inhibit mandrel protrusion and the potential tissue damage associated therewith.