Necked Catheter Tip Forming Method
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Solution Overview
Problem
Intraluminal catheters face challenges in forming a distal tip with a reduced diameter and thickness that is both flexible and strong enough to prevent guidewire lumen collapse during vascular procedures, while minimizing vessel injury in tortuous anatomy.
Innovation Solution
The method involves necking down a polymeric inner tubular member using a stepped mandrel and removing material from the inner surface of the necked tip to create a soft, flexible tip with a small entry profile, using techniques like hot die forming, milling, or laser ablation, and monitoring the removal depth to ensure the tip's strength and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the catheter tip diameter and thickness are reduced to improve flexibility and trackability, then the tip becomes more flexible and trackable, but the tip strength decreases and may collapse the guidewire lumen
Solution Approach 1:
The catheter shaft is designed with non-uniform wall thickness, where the distal tip portion has reduced wall thickness compared to proximal portions. This creates a gradient structure where the tip is softer and more flexible for navigation, while proximal sections maintain sufficient strength for structural support and guidewire lumen prevention.
Solution Approach 2:
The catheter tip is formed as a distinct segment with different geometric and material properties from the rest of the shaft. The necking process creates a transition zone that segments the structure into a soft tip region and a stronger shaft region, allowing each to optimize its function independently.
2Object-affected harmful factors
If the catheter tip diameter is reduced to minimize vessel injury, then vessel trauma is reduced, but the tip becomes more prone to collapsing the guidewire lumen
Solution Approach 1:
The catheter employs localized thinning at the distal tip through controlled necking, creating a soft tip with reduced outer diameter that minimizes vessel trauma. The wall thickness gradient ensures that only the tip portion is softened, while proximal sections maintain adequate structural integrity to support the guidewire lumen and prevent collapse.
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
This approach results in a catheter tip that provides improved trackability and flexibility while maintaining sufficient strength to prevent guidewire lumen collapse, reducing vessel injury during advancement in vascular procedures.
Implementation Method 1
The tubular member can be necked down using a hot die having an inner diameter, wherein the necked tip has an outer diameter about equal to the inner diameter of the hot die.
Implementation Method 2
The portion of polymeric material removed from the inner surface along the necked tip can be removed by a rotary device.
Implementation Method 3
Additionally or alternatively, the portion of polymeric material removed from the inner surface along the necked tip can be removed by milling or laser ablation.
Data Source
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AI summary
Method for fabricating a catheter including providing an inner tubular member formed from a first polymeric material, the inner tubular member having a distal section, a distal end, and a lumen defined therein by a first inner diameter; necking down at least a portion of the distal section of the inner tubular member to form a necked tip having a second inner diameter; and removing a portion of polymeric material from an inner surface along the necked tip to define a third inner diameter for the necked tip. The method can include positioning the distal section of the inner tubular member in a balloon having a working length, a distal neck, and a distal leg, with the distal end of the inner tubular member extending distally beyond a distal end of the distal leg, and coupling the distal leg of the balloon to at least a portion of the distal section of the inner tubular member.