Hypotube Flexibility via Offset Circumferential Cuts
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Solution Overview
Problem
Conventional stainless steel hypotubes used in medical devices tend to kink when navigating tortuous paths, while nitinol alternatives are more expensive to manufacture, especially in small quantities.
Innovation Solution
Incorporating a series of circumferentially arranged cuts along the length of a stainless steel or nitinol hypotube to enhance flexibility, with rotational offsets and varying arc lengths to maintain structural integrity and prevent kinking, and employing laser cutting techniques to reduce manufacturing time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional stainless steel hypotubes are used, then manufacturing cost is low and structural integrity is maintained, but flexibility is poor and kinking occurs in tortuous paths
Solution Approach 1:
The hypotube is segmented by introducing a series of circumferential cuts along its length. These cuts divide the continuous tube wall into multiple sections, allowing each segment to move independently and accommodate tortuous paths without kinking, while the overall tube maintains structural integrity through the distributed nature of the cuts
Solution Approach 2:
The hypotube has non-uniform properties along its length: sections with circumferential cuts provide flexibility and kink-resistance where needed, while sections without cuts maintain full structural integrity. This local differentiation allows the tube to have both flexible and strong regions in the same component
2Adaptability or versatility
If nitinol material is used to form hypotubes, then kink-resistance and flexibility are improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent changes the geometric parameters of the stainless steel hypotube by introducing circumferential cuts with specific arc lengths and spacing. This parameter modification enables the tube to achieve kink-resistance and flexibility comparable to nitinol, but without the high material and manufacturing costs associated with nitinol processing
3Adaptability or versatility
If circumferential cuts are introduced to enhance flexibility, then kink-resistance is improved, but structural integrity may be compromised
Solution Approach 1:
The circumferential cuts extend only partially around the tube circumference rather than completely. This partial action provides enough flexibility enhancement to prevent kinking while leaving sufficient material intact to maintain structural integrity and prevent tube collapse or failure
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 flexibility-enhanced hypotubes are less likely to kink and maintain structural integrity, reducing the likelihood of kinking and fluid flow disruption while minimizing manufacturing time and costs by up to 40% without compromising flexibility.
Implementation Method 1
employing laser cutting techniques to reduce manufacturing time and costs
Data Source
AI summary
An elongated medical device includes an elongated tubular element with a series of flexibility enhancing features along a length of the elongated tubular element. Each flexibility enhancing feature may include a circumferential series of cuts. The cuts of one flexibility enhancing feature may be offset relative to the cuts of a longitudinally adjacent flexibility enhancing feature. The flexibility enhancing features may be grouped into two or more interleaved sets, with each set of circumferential cuts being offset relative to the next set of circumferential cuts. Methods for manufacturing such elongated medical devices are also disclosed.