Needle Sheath With Cut Hypotube Insert
Solution Overview
Problem
The existing needle sheath configurations for endobronchial ultrasound (EBUS) working channels, particularly those with polytetrafluoroethylene (PTFE) sheaths and coils, face issues such as needle tip snagging, perforation, and increased resistance during activation, along with complex and costly manufacturing processes due to the coil's low column strength.
Innovation Solution
A needle sheath with a protective hypotube made of stainless steel, featuring radial or spiral cuts, is integrated within a polymer sheath, allowing for radial expansion and improved flexibility, reducing snagging risks and manufacturing complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coil is added to the distal end of the PTFE sheath to protect the EBUS working channel, then the protection capability is improved, but the needle activation resistance increases and the manufacturing complexity increases
Solution Approach 1:
The patent removes the coil component from the sheath structure entirely. Instead of adding protective elements that create friction, the invention uses a smooth-bored hypotube made of PTFE or similar low-friction material that naturally protects the working channel while allowing the needle to advance freely without snagging on coils or protrusions.
Solution Approach 2:
The patent changes the material parameters of the sheath by using PTFE or other low-friction materials with specific surface properties that reduce coefficient of friction. The hypotube is smooth-bored to specific tolerances to ensure minimal resistance to needle advancement while maintaining structural integrity and protection capabilities.
2Reliability
If a coil is added to the distal end of the PTFE sheath to protect the EBUS working channel, then the protection capability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent eliminates the coil component and its associated manufacturing steps (coiling, attachment, positioning). The sheath is manufactured as a simple extruded or drawn tube with a smooth interior bore, requiring only basic machining operations rather than complex assembly processes.
Solution Approach 2:
The patent uses composite construction combining PTFE lining or coating with a supportive hypotube structure. This composite approach provides both protection and structural integrity while maintaining manufacturing simplicity through extrusion or drawing processes that create the final structure in one operation.
3Strength
If the metal tube outer diameter is made greater than the lumen diameter for structural support, then the strength is improved, but the assembly complexity increases
Solution Approach 1:
The patent specifies precise dimensional parameters where the hypotube outer diameter is slightly larger than the sheath inner diameter, creating an interference fit. This parameter optimization provides structural support through friction and radial pressure while allowing simple push-fit assembly without complex fastening mechanisms.
Solution Approach 2:
The patent employs self-assembly through interference fit where the components join automatically through friction and radial pressure when pushed together. The assembly process requires no additional fastening steps, tools, or complex procedures - the components self-lock through their dimensional relationship and material properties.
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 enhances the ease of needle advancement, minimizes snagging and kinking, and simplifies the assembly process, providing a more reliable and efficient delivery system for EBUS procedures.
Implementation Method 1
a force is applied to at least one of the sheath or a metal tube until the metal tube is fully received with in the sheath, wherein the sheath expands radially at a region occupied by the metal tube
Implementation Method 2
a thermal forming process is performed on the sheath distal from a distal end of the metal tube
Data Source
AI summary
A needle apparatus having a sheath with a protective hypotube insert and a method of making the needle sheath. An example needle apparatus includes a handle, a needle having a proximal end connected to the handle and a sheath. The sheath is configured to receive of the needle. The sheath includes a proximal end connected to the handle, a distal end, a lumen and the protective insert. The lumen passes from the proximal end to the distal end of the sheath. The protective insert is received within the lumen at the distal end of the sheath when force and/or heat are applied.