Double-Leaf Spring Stent with Dynamic Radial Force
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Solution Overview
Problem
Existing stents for aspiration thrombectomy face challenges in providing sufficient radial force at the target site to resist negative pressures while maintaining steerability through tortuous structures, leading to tradeoffs between device deliverability and bore size.
Innovation Solution
A double-leaf spring stent design with a novel spring arrangement that exerts reduced radial force in the collapsed state for delivery and increased radial force in the expanded state, utilizing a combination of curved and vertical arms to achieve non-linear radial force profiles, enhancing deliverability and steerability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a covered self-expanding stent is used to increase bore size for aspiration thrombectomy, then the bore size is improved, but the radial force becomes insufficient to withstand vacuum pressures
Solution Approach 1:
The stent employs a dynamic radial force profile where the radial force varies during expansion and compression cycles. The non-linear spring structure provides high radial force during expansion to withstand vacuum pressures, then reduces radial force during compression to improve deliverability through tortuous vessels.
Solution Approach 2:
The invention changes the radial force parameter dynamically through its non-linear spring geometry. The double-leaf spring configuration with varying arm lengths and angles creates a radial force profile that peaks during expansion and decreases during compression, resolving the contradiction between needing high radial force for pressure resistance and low radial force for deliverability.
2Strength
If a stent with higher radial force is used to withstand vacuum pressures, then the strength is improved, but the deliverability through narrow twisting spaces deteriorates
Solution Approach 1:
The stent's radial force is dynamic rather than static. During delivery through tortuous vessels, the stent is compressed and the radial force decreases naturally. Upon expansion at the target site, the radial force increases to withstand vacuum pressures. This dynamic behavior resolves the contradiction between strength and deliverability.
Solution Approach 2:
The stent undergoes periodic compression and expansion cycles during delivery and use. The non-linear spring structure ensures that radial force is high during the expansion phase (when strength is needed) and low during the compression phase (when deliverability is needed), creating a periodic force profile that satisfies both requirements.
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 double-leaf spring stent improves deliverability and steerability by reducing friction during delivery and maintaining strong radial forces during aspiration, allowing for effective hyper-expansion of the aspiration bore and resistance to negative pressures.
Implementation Method 1
a spring structure configured to exert a collapsed radial force in a collapsed state; exert an expanded radial force in an expanded state; and exert a peak radial force during a transition of the spring structure between the collapsed state and the expanded state
Data Source
AI summary
Embodiments of the present disclosure relate to an expandable stent and method for using same. An example expandable stent includes a spring structure configured to exert a collapsed radial force in a collapsed state; exert an expanded radial force in an expanded state, the collapsed radial force being greater than the expanded radial force; and exert a peak radial force during a transition of the spring structure between the collapsed state and the expanded state, wherein the peak radial force is greater than the collapsed radial force and greater than the expanded radial force. The example spring structure may include a plurality of double-leaf springs.