Self-adjusting Catheter Segment for Vessel Navigation
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Solution Overview
Problem
Existing suction catheters face challenges in navigating tortuous blood vessels, particularly at branch points like the cavernous sinus and petrous bone, leading to frequent sticking and kinking issues that hinder access to clots during thrombectomy procedures.
Innovation Solution
The development of a catheter with a distensible segment that undergoes a conformational change from a relaxed cylindrical shape to a distended non-cylindrical shape when encountering a vessel wall, allowing the catheter to self-adjust and dislodge from the wall without kinking the proximal segment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the catheter is made with uniform stiffness along its entire length to resist deformation, then the catheter maintains structural stability, but the catheter gets stuck at vessel turns and branch points due to inability to navigate tortuous anatomy
Solution Approach 1:
The catheter is divided into three distinct segments: a proximal segment with higher stiffness for structural stability, a distal segment with lower stiffness for navigation flexibility, and an intermediate transition segment that provides a gradient transition between the two. This segmentation allows each segment to perform its specific function optimally without compromising the overall catheter performance.
Solution Approach 2:
Different segments of the catheter are assigned different mechanical properties (stiffness values) according to their specific functional requirements. The proximal segment has higher stiffness to maintain stability during manipulation, while the distal segment has lower stiffness to navigate tortuous vessels, and the intermediate segment provides a gradual transition. This local differentiation of material properties resolves the contradiction between overall stability and local adaptability.
2Ease of operation
If the catheter distal end is pushed distally to dislodge from the vessel wall, then the catheter may be dislodged from the ledge, but the proximal segment kinks and folds back onto itself due to the pushing force
Solution Approach 1:
The catheter is segmented into proximal, intermediate, and distal sections with different stiffness characteristics. When the distal end is pushed to dislodge from the vessel wall, the flexible distal segment and compliant intermediate segment absorb the pushing force through controlled deformation, preventing force transmission that would cause kinking in the proximal segment. This segmentation isolates the deformation to specific zones.
Solution Approach 2:
The catheter incorporates dynamic compliance through its segmented structure, allowing it to adapt its rigidity based on operational needs. The intermediate transition segment provides a gradient of stiffness that enables controlled flexibility during dislodgement maneuvers, allowing the catheter to dynamically respond to forces applied at the distal end without transmitting damaging stresses proximally.
3Adaptability or versatility
If a guide wire is used to help navigate the catheter through tortuous vessels, then the catheter can be guided better, but the guide wire can disrupt the clot and add to the procedure time
Solution Approach 1:
The catheter is designed with inherent navigation capabilities through its segmented structure, where the distal flexible segment and intermediate transition segment enable the catheter to self-navigate through tortuous vessels and branch points without requiring external assistance from guide wires. The catheter's own mechanical properties provide the necessary adaptability, eliminating the need for additional devices that would slow down the procedure.
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
This design enables the catheter to effectively navigate complex vascular anatomy, reduce sticking and kinking issues, and improve access to clots, thereby enhancing the efficiency and success rate of thrombectomy procedures.
Implementation Method 1
a distensible segment located between the proximal and distal segments that is configured to undergo a conformational change when a linear force in the distal direction is applied to the catheter and, in turn, a linear force in the proximal direction is applied to the catheter open distal end
Data Source
AI summary
Catheters and uses of same are described. The catheter may be an aspiration or distal access catheter used to treat stroke or other neurovascular conditions and may include a proximal segment and a distal segment with fixed shapes and outer diameters, and a distensible segment that is located proximal to the distal segment and adjacent to the catheter distal end and that is configured to undergo a conformation change when the catheter open distal end is lodged against the wall of a human blood vessel and a surgeon is attempting to move the catheter distally through the human blood vessel. The catheter may include a wall that is comprised of an inner tube surrounding the catheter's hollow interior, a coil surrounding the inner tube, a braid surrounding the coil and/or an outer tube surrounding the braid. The pitch of the coil may be greater in the distensible segment as compared to the proximal segment and the outer tube may not be attached to the inner tube for at least a portion of the distensible segment, which features allow for the distensible segment to undergo the conformational change. The distal segment may include a metallic marker band, providing rigidity to the distal segment.