Friction-Fit Anchor for Shape Memory Medical Devices
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Solution Overview
Problem
Developing a barb for use with wire, shape memory material medical devices is challenging, particularly due to difficulties in attaching barbs to shape memory alloys like nickel-titanium without affecting the fatigue properties of the alloy, and existing solutions like cannula-cut barbed stents are more expensive.
Innovation Solution
A medical device anchor comprising a coil with a barb and a turn connecting it, arranged to tighten radially around an elongate member upon stretching, fixed by a friction fit without crimping, welding, soldering, or adhesive, allowing for a cost-effective and stress-neutral attachment to shape memory wire components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soldering is used to attach barbs to nickel-titanium stents, then the attachment strength is improved, but the fatigue properties of the alloy are affected and the solder joint degrades over time
Solution Approach 1:
The patent replaces thermal joining methods (soldering) with a mechanical attachment system. The barb is mechanically engaged with the stent structure through a friction-fit interface, eliminating the need for soldering while maintaining attachment strength. This mechanical approach preserves the fatigue properties of the nickel-titanium alloy by avoiding thermal exposure and stress concentrations associated with solder joints.
Solution Approach 2:
The patent introduces an intermediary friction-fit interface between the barb and stent. This interface acts as a mediator that transfers loads without requiring direct metallurgical bonding, thereby protecting the alloy's fatigue properties while achieving reliable attachment.
2Ease of manufacture
If cannula-cut barbed stents are used, then the integration of barbs is improved, but the manufacturing cost increases
Solution Approach 1:
The patent segments the barb and stent as separate components that are subsequently assembled through friction-fit attachment. This segmentation allows each component to be manufactured independently using cost-effective processes, avoiding the expensive cannula-cutting operation while achieving integrated functionality through simple mechanical assembly.
Solution Approach 2:
The patent employs a simple, inexpensive barb design that can be manufactured at low cost and attached via friction-fit. This approach sacrifices the need for expensive integrated manufacturing in favor of cheaper, modular components that achieve the same functional outcome.
3Strength
If traditional attachment methods (crimp, weld, solder, adhesive) are used, then the fixation strength is improved, but manufacturing complexity and potential toxic hazards increase
Solution Approach 1:
The patent employs a self-service friction-fit attachment mechanism where the barb and stent components self-secure through frictional forces without requiring external attachment processes. This eliminates the need for crimping, welding, soldering, or adhesive application, thereby reducing manufacturing complexity and eliminating associated toxic hazards while maintaining fixation strength.
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 anchor effectively grips the medical device, maintaining its position within a body vessel by reacting to hemodynamic forces, reducing manufacturing costs and avoiding the mechanical and toxic hazards associated with traditional attachment methods.
Implementation Method 1
The coil is arranged on the elongate member so that, in the event that the coil is stretched longitudinally, it tightens (for example by contracting radially) and thus may grip the elongate more tightly in reaction to the stretching
Implementation Method 2
The anchor may be fixed to the elongate member by a friction fit
Data Source
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AI summary
Disclosed herein is an anchor for use with a medical device. The anchor includes a coil, a barb, and a turn connecting the coil to the barb. The anchor may be made of a shape memory material. The coil may have a first handedness, and the turn may have a second handedness opposite the first handedness. The anchor may be attached to the medical device by a friction fit, in some cases without being attached by welding, soldering, adhesive, or crimping.