Introducer Sheath Braided Filament Securement
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Solution Overview
Problem
Existing introducer sheaths face challenges with kink resistance and fraying of braided filaments during manufacturing, leading to manufacturing rejects and reduced effectiveness in traversing tortuous passageways without increasing sheath thickness.
Innovation Solution
A tubular medical device with a braided member and a securement mechanism at the distal end to inhibit filament movement, using radiopaque solder to rigidly fuse intersecting filaments and maintain the thinness of the sheath wall, combined with a coiled member for enhanced kink resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the sheath wall is made thinner to reduce trauma and occupy less space in the vessel, then the sheath becomes more flexible and causes less trauma, but the kink resistance deteriorates
Solution Approach 1:
The sheath employs a composite construction combining a thin-walled fluorocarbon tube with a braided member made of flexible memory alloy wires (such as nitinol). The braided member is positioned within the tube to provide kink resistance while the thin fluorocarbon wall maintains flexibility and minimizes trauma. This composite structure allows the sheath to be both thin and kink-resistant.
2Strength
If the sheath wall is thickened to improve kink resistance, then the kink resistance improves, but the diameter of the interventional device that can be passed is reduced and the entry opening must be larger
Solution Approach 1:
The sheath uses a composite structure where a thin-walled fluorocarbon tube provides flexibility and a small outer diameter, while an internal braided member of flexible memory alloy wires provides the necessary kink resistance. This allows the sheath to maintain a small profile for passing through narrow vessels while resisting kinking during insertion through tortuous pathways.
3Strength
If a braided member is added to improve kink resistance, then the kink resistance improves, but the fraying of braided filaments during manufacturing increases
Solution Approach 1:
The patent replaces traditional mechanical securement methods (such as glazing or crimping) with a laser welding process to attach the distal end of the braided member to the fluorocarbon tube. This thermal joining method provides reliable attachment without the filament damage associated with mechanical compression or chemical adhesives, thereby reducing manufacturing rejects.
Solution Approach 2:
The invention changes the attachment method parameters from mechanical or chemical processes to laser thermal welding. This parameter change allows for precise control of the joining process, creating a strong bond between the braided member and tube while minimizing thermal damage to the delicate filaments, thus improving manufacturing reliability.
4Stability of the object's composition
If traditional securement methods are used to prevent fraying, then filament security improves, but the manufacturing complexity and rejects increase
Solution Approach 1:
The patent replaces complex mechanical securement systems (such as glazing machines or crimping devices) with a laser welding system. This substitution simplifies the manufacturing process by using a precise, automated thermal joining process that securely attaches the braided member to the tube without the complexity of mechanical or chemical attachment methods.
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 solution provides improved kink resistance and reduced fraying, allowing for effective traversal of tortuous anatomy while maintaining a thin sheath wall, thereby enhancing the reliability and usability of introducer sheaths in minimally invasive procedures.
Implementation Method 1
The securement mechanism can include a radiopaque solder material
Implementation Method 2
a coiled member disposed along an outer surface of the inner liner
Data Source
AI summary
A tubular body for a medical device for insertion within a body passageway of a patient. The tubular body includes a tubular inner liner. A braided member is disposed along an outer surface of the liner. The braided member includes intersecting filaments and cells defined by the filaments. A securement mechanism, such as radiopaque solder, is disposed along a circumferential region of the braided member. The securement mechanism is attached to portions of the filaments and spans the cells that correspond to the circumferential region to inhibit relative movement of filament ends. An outer surface of the securement mechanism is sized to extend radially outward to a position up to an outer surface of the braided member to not add to the overall wall thickness of the tubular body. An outer jacket is positioned longitudinally around the braided member and connected to the inner liner.