Helical Guiding Device Tip for CTO Crossing
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Solution Overview
Problem
Guiding devices face challenges in navigating through tortuous vasculature and crossing chronic total occlusions (CTOs) without perforating the vessel wall, as they need to balance flexibility for navigation with stiffness to overcome occlusions and maintain central alignment within the true lumen.
Innovation Solution
A guiding device with a dilatable tip featuring helical members made of nickel-titanium alloy, which increases in stiffness when rotated in a winding direction, allowing for drilling action and radial displacement of lesions, and can be adjusted for flexibility and stiffness through torque and axial forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the guiding device is made flexible to navigate tortuous vasculature, then navigation capability is improved, but the ability to overcome friction and occlusions deteriorates
Solution Approach 1:
The guiding device is divided into multiple segments with different stiffness characteristics. The distal portion contains helical members that can be independently activated to provide localized stiffness enhancement, while the proximal portion maintains flexibility for navigation. This segmentation allows the device to exhibit context-dependent mechanical properties.
Solution Approach 2:
The guiding device transitions from a static stiffness structure to a dynamic one where the stiffness of the distal portion can be adjusted in real-time. By rotating the outer tubular member relative to the inner tubular member, the helical members wind or unwind, dynamically changing the device's pushability and flexibility characteristics during the procedure.
2Force
If the guiding device is made stiff to cross occlusions, then the ability to overcome friction and occlusions is improved, but the ability to navigate tortuous pathways deteriorates
Solution Approach 1:
The guiding device is divided into multiple segments with different stiffness characteristics. The distal portion contains helical members that can be independently activated to provide localized stiffness enhancement, while the proximal portion maintains flexibility for navigation. This segmentation allows the device to exhibit context-dependent mechanical properties.
Solution Approach 2:
Different portions of the guiding device have different mechanical properties. The distal portion is designed with helical members that can provide high stiffness when needed for lesion crossing, while the proximal portion maintains inherent flexibility for navigation through tortuous vasculature. This local differentiation resolves the contradiction between overall device stiffness and flexibility.
3Stability of the object's composition
If the tip of the guiding device is made stiff to maintain central alignment, then alignment stability is improved, but the risk of vessel perforation increases
Solution Approach 1:
The stiffness of the distal tip is made dynamic rather than static. The helical members can be wound to increase stiffness for maintaining central alignment during advancement, then unwound to decrease stiffness and reduce perforation risk when crossing lesions. This dynamic adjustment allows the device to adapt its mechanical properties to the immediate procedural needs.
Solution Approach 2:
The mechanical parameters of the guiding device, specifically the stiffness of the distal portion, are changed during the procedure. By rotating the tubular members to wind or unwind the helical structures, the operator can continuously adjust the stiffness parameter to match the requirements of different procedural phases, thereby optimizing both alignment stability and safety.
4Ease of operation
If the guiding device is made torqueable to facilitate directional changes, then steerability is improved, but the complexity of the device increases
Solution Approach 1:
The helical members serve multiple functions: they provide stiffness enhancement for lesion crossing, enable torque transmission for directional control, and can be adjusted to modify the device's mechanical properties. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity despite the added steerability capabilities.
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
Enables effective crossing of CTOs by minimizing the risk of vessel perforation and subintimal deflection, facilitating the introduction of other intravascular devices while maintaining central alignment within the vessel lumen.
Implementation Method 1
the tip increases in stiffness when the helical members are tensioned by a resistance to rotation in the winding direction
Implementation Method 2
the tip includes a plurality of helical members having a wound configuration such that resistance to rotation in an unwinding direction dilates the tip and wherein the helical members form threads configured to provide a drilling action when the guiding device is rotated in a winding direction
Implementation Method 3
the helical members are formed from nickel-titanium alloy
Implementation Method 4
the helical members are formed from nickel-titanium alloy
Data Source
AI summary
This disclosure is directed to systems and methods for providing a guiding device having a dilatable, drilling tip. The tip is formed by wound helical members such that resistance to rotation in an unwinding direction dilates the tip. The helical members are configured so that the dilatable tip increases in stiffness when the helical members are tensioned by a resistance to rotation in the winding direction. In some embodiments, application of relative force between coaxial inner and outer tubular members is used to control the dilation, stiffness and drilling of the guiding member.