Medical Guide Element Diameter Transition
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Solution Overview
Problem
Current percutaneous vascular access techniques, such as the Seldinger-Desilets-Hoffman method, face challenges including trauma and tearing of blood vessel walls due to the abrupt transition in diameter from the guidewire to the dilator tip, leading to resistance and complications during catheter insertion.
Innovation Solution
A novel guide element with an abrupt, annular circumferential step transition that shields the dilator tip, reducing the diameter difference between the guidewire and dilator, allowing for smooth dilation and minimizing trauma to the vessel wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dilator with a tip diameter larger than the guidewire diameter is used, then the dilator can effectively dilate the puncture hole, but the abrupt diameter transition causes trauma and tearing of the blood vessel wall
Solution Approach 1:
The guide element is divided into two segments with different diameters: a proximal segment with a smaller diameter that fits through the needle, and a distal segment with a larger diameter that shields the dilator tip. This segmentation creates a gradual transition zone that reduces vessel wall trauma while maintaining the dilator's effectiveness.
Solution Approach 2:
The distal segment of the guide element acts as an intermediary between the guidewire and the dilator tip. It provides a intermediate diameter that bridges the gap between the small guidewire and the large dilator tip, preventing abrupt diameter transitions and reducing mechanical trauma to the vessel wall.
2Object-affected harmful factors
If the dilator tip diameter is reduced to match the guidewire diameter, then vessel wall trauma is minimized, but the dilator cannot effectively dilate the puncture hole
Solution Approach 1:
The dilator system is segmented into the guide element (with proximal and distal segments of different diameters) and the dilator proper. The distal segment provides the smaller diameter for gentle insertion, while the main body of the dilator provides the larger diameter for effective dilation of the puncture hole.
Solution Approach 2:
The solution transitions from a single-diameter design to a multi-diameter design along the longitudinal dimension. The guide element's diameter changes along its length, with the distal segment having a smaller diameter for insertion and the proximal segment having a larger diameter that matches the dilator's internal diameter, enabling both gentle insertion and effective dilation.
3Productivity
If a larger diameter guidewire is used to reduce the diameter difference with the dilator, then dilation effectiveness is improved, but the guidewire cannot pass through the needle bore
Solution Approach 1:
The guide element is segmented into a proximal segment with a smaller diameter that fits through the needle bore, and a distal segment with a larger diameter that provides better diameter matching with the dilator. This segmentation allows the guide element to satisfy both constraints: passing through the needle and reducing the diameter transition to the dilator.
Solution Approach 2:
The guide element's diameter is made variable along its length rather than uniform. The proximal portion has a smaller diameter for needle compatibility, while the distal portion has a larger diameter for dilator compatibility. This dimensional variation along the longitudinal axis resolves the contradiction between needle passage and dilation effectiveness.
4Ease of operation
If the dilator tip is exposed without shielding, then the dilator can be inserted directly, but the tip becomes frayed and deformed during passage through tissue
Solution Approach 1:
The distal segment of the guide element serves as a shielding intermediary that protects the dilator tip during insertion. It covers and shields the dilator tip from mechanical damage caused by tissue friction and contact, preventing fraying and deformation while maintaining insertion simplicity.
Solution Approach 2:
The dilator tip is shielded by the distal segment of the guide element before insertion begins. This pre-protection prevents mechanical damage to the dilator tip during the insertion process through tissue, ensuring tip integrity is maintained throughout the procedure.
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
Improved medical filaments for use with dilators to be inserted into a patient, for example into the vascular lumen, are provided, as well as combinations of filaments and dilators Methods for use of such filaments and filament-dilator combinations are also described. The filament includes a proximal segment and a distal segment. The diameter of the distal segment is greater than the diameter of the proximal segment. The change in diameter is abrupt, providing a discrete step transition at a point along the filament which presents a proximally-facing surface on the distal segment When the proximal segment of the filament is fully inserted into a dilator having a distal tip adapted for insertion into a patient, the dilator distal tip firmly abuts the proximally-facing end surface of the distal segment.