Variable Width Stent Struts for Intracranial Flexibility
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Solution Overview
Problem
Current stents for treating wide-necked intracranial aneurysms face challenges in balancing flexibility to navigate tight curves and structural integrity to maintain embolic coil coverage, with open cell stents being more flexible but harder to recapture and closed cell stents lacking conformity.
Innovation Solution
The development of stents with multiple longitudinal elements featuring alternated flexible and rigid segments, interconnected by nodes and branches, allowing for both lateral and longitudinal flexibility while maintaining structural integrity, similar to a closed cell design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If open cell stent design is used to increase flexibility for navigating tight curves, then flexibility is improved, but structural integrity and scaffolding uniformity deteriorate
Solution Approach 1:
The stent is segmented into alternating flexible segments and rigid segments along its longitudinal elements. This segmentation allows different portions of the stent to perform different functions: flexible segments enable navigation through tight curves while rigid segments provide structural support and maintain scaffolding uniformity when deployed.
Solution Approach 2:
Different segments of the stent are given different mechanical properties - some segments are designed to be flexible while others are designed to be rigid. This local differentiation of quality allows the stent to simultaneously achieve flexibility for navigation and structural integrity for aneurysm support without compromising either function.
2Strength
If closed cell stent design is used to maintain structural integrity and scaffolding uniformity, then structural integrity is improved, but flexibility for navigating tight curves deteriorates
Solution Approach 1:
The closed cell structure is segmented into alternating flexible and rigid segments. This allows the stent to maintain the structural benefits of closed cell design while introducing flexibility in specific segments to enable navigation through the tortuous intracranial vasculature.
Solution Approach 2:
The stent transitions from a static uniform structure to a dynamic structure with varying flexibility along its length. The alternating flexible and rigid segments allow the stent to adapt its mechanical properties along its longitudinal axis, providing rigidity where structural support is needed and flexibility where navigation is required.
3Adaptability or versatility
If open cell stent design is used to improve flexibility, then ease of navigation is improved, but recapturability deteriorates
Solution Approach 1:
The alternating flexible and rigid segments work together to maintain the closed cell structure's ability to be recaptured and repositioned while still providing the flexibility needed for navigation. The structured alternation of segment types preserves the overall closed cell geometry that enables recapturability.
Data Source
AI summary
Stents generally can include multiple longitudinal elements each extending over a majority of the length of the stent and each having alternating flexible and rigid segments. The stents can include nodes positioned between the flexible and rigid segments on the longitudinal elements and interconnecting members extending circumferentially to connect adjacent longitudinal elements at the nodes. The longitudinal elements can have a wave pattern and the interconnecting members can have a branch structure connecting peaks from one longitudinal element to troughs of an adjacent longitudinal element. The resulting stent structure can have lateral and longitudinal flexibility needed to navigate and conform to intracranial arteries with the benefits of recapturability and structural integrity of a closed cell design.