Helically Wound Catheter Support for High ID-to-Wall Ratio
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Solution Overview
Problem
Current medical catheter technologies face limitations in providing adequate support and guidance for stent delivery and other catheters, particularly in procedures like coronary artery disease treatment, where a high inner diameter to wall thickness ratio and radiopacity are crucial for effective intervention.
Innovation Solution
A device comprising a tubular guiding member with a thin wall and high inner diameter to wall thickness ratio, featuring a helically wound support structure and an encapsulation layer made from thermoplastic materials, which is mechanically interlocked and adhered to the support structure, allowing for enhanced flexibility and visibility during medical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional catheter support structure is used, then structural strength is maintained, but the inner diameter to wall thickness ratio is insufficient and flexibility is reduced
Solution Approach 1:
The catheter incorporates a composite structure with a polymer base material reinforced by a helically-wound radiopaque support member. This composite construction provides both the necessary structural strength and the high inner diameter to wall thickness ratio, as the helical winding provides reinforcement without requiring a thick wall construction.
Solution Approach 2:
The support member is wound in a helical pattern around the catheter body, creating a curved reinforcement structure. This helical configuration provides structural support while maintaining flexibility and achieving the desired high inner diameter to wall thickness ratio, as the curved geometry distributes stress efficiently without requiring straight rigid supports.
2Strength
If a thicker wall catheter is used, then structural support is improved, but the inner diameter to wall thickness ratio decreases and flexibility is reduced
Solution Approach 1:
The catheter uses a composite structure where a thin-walled polymer tube is reinforced by a helically-wound support member made of radiopaque material. This allows the wall to remain thin (maintaining high inner diameter to wall thickness ratio) while the helical reinforcement provides the necessary structural support that would otherwise require a thicker wall.
Solution Approach 2:
The helical winding of the support member creates a curved reinforcement pattern that provides structural strength without increasing wall thickness. The helical geometry allows the thin-walled construction to maintain both flexibility and structural integrity, achieving the desired high inner diameter to wall thickness ratio.
3Illumination intensity
If radiopaque materials are added for visibility, then procedural visibility is improved, but the catheter structure becomes more complex
Solution Approach 1:
The radiopaque support member serves multiple functions simultaneously: it provides structural reinforcement to the catheter wall and provides radiopacity for procedural visibility. By combining these two functions into a single component, the design avoids adding separate radiopaque marker elements, thus maintaining structural simplicity while achieving both support and visibility requirements.
Solution Approach 2:
The helically-wound support member is designed to perform multiple functions: structural reinforcement of the thin-walled catheter and radiographic visibility during procedures. This multi-functional element eliminates the need for separate components, reducing overall device complexity while achieving both support and visibility goals.
4Reliability
If encapsulation material is applied over the support structure, then mechanical interlocking and adhesion are achieved, but manufacturing complexity increases
Solution Approach 1:
The encapsulation material is applied in a molten or softened state and then allowed to cool and solidify, forming a mechanically interlocked structure with the helical support member. This phase transition approach allows the material to flow into and around the helical geometry, creating strong mechanical interlocking and adhesion without requiring complex assembly operations.
Solution Approach 2:
The encapsulation material is applied over the support structure during the catheter manufacturing process, before final assembly and sterilization. This preliminary application ensures that the mechanical interlocking and adhesion are established early in the manufacturing sequence, simplifying subsequent processing steps and reducing overall manufacturing complexity.
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
Enables new treatment options by providing a robust yet flexible catheter support system that can be used in conjunction with stent delivery and other catheters, improving procedural efficacy and visibility during interventions like coronary artery disease treatment.
Implementation Method 1
the thermoplastic material having melted, mixed and solidified during a reflow process
Implementation Method 2
the thermoplastic material having melted, mixed and solidified during a reflow process
Data Source
AI summary
A device for guiding and supporting a stent delivery catheter and other catheters is disclosed. The device may comprise a tubular guiding member and an elongated positioning member extending in a proximal direction beyond the tubular guiding member for advancing and retracting the tubular guiding member in distal and proximal directions. A distal portion of the elongate positioning member may be coupled to the proximal portion of the tubular guide. In embodiments, the device includes a ribbon having a distal portion and a proximal portion. In embodiments, the distal portion of the ribbon extends distally into the tubular guiding member and the proximal portion of the ribbon overlays an inner surface of the elongate positioning member. Methods for making medical devices and portions of medical devices (e.g., intravascular catheters, catheter shafts, and tubular guiding members) are also provided. Example methods may include providing a first ribbon comprising one or more thermoplastic materials and a piece of shrink tubing defining a shrink tube lumen and forming a first assembly by positioning the first ribbon inside the shrink tube lumen and urging the first ribbon to assume a tubular shape in which the first ribbon defines a ribbon lumen. A second assembly may be formed by loading an inner tubular member over a mandrel and forming or placing a support structure over an outer surface of the inner tubular member. A third assembly may be formed by inserting the second assembly into the ribbon lumen defined by the first ribbon of the first assembly. The third assembly may be heated to a process temperature.