Self-adjusting Catheter Segment Navigating Tortuous Vessels
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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 getting stuck and kinking, which hinders access to clots during thrombectomy procedures.
Innovation Solution
The catheter design incorporates a distensible segment that self-adjusts from a relaxed cylindrical configuration to a distended non-cylindrical configuration when lodged against a vessel wall, allowing it to bulge outward and dislodge 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 it gets stuck at vessel turns and branch points due to inability to navigate tortuous vessels
Solution Approach 1:
The catheter is divided into multiple segments with different flexibility characteristics: a proximal segment with higher stiffness for structural stability, a distal segment with lower stiffness for navigation, and an intermediate segment providing transition. This segmentation allows the catheter to simultaneously maintain stability while adapting to tortuous vessel paths.
Solution Approach 2:
Different portions of the catheter are given different mechanical properties - the proximal segment has higher stiffness to resist deformation during aspiration, while the distal segment has lower stiffness to navigate tortuous vessels and branch points. This local differentiation of material properties resolves the contradiction between overall stability and local adaptability.
2Length of moving object
If the catheter distal end is pushed distally to access clots in distant vessels, then the catheter reaches the target location, but the proximal segment kinks and folds back when the distal end gets stuck on a ledge
Solution Approach 1:
The catheter's segmented construction with varying flexibility allows the distal segment to absorb pushing forces through controlled deformation rather than transmitting them to the proximal segment. This prevents kinking while maintaining the ability to reach distant vessel locations.
Solution Approach 2:
The catheter transitions from a static, uniform structure to a dynamic, gradient-structured system where flexibility varies along its length. This dynamic design allows different segments to respond differently to forces - the distal segment deforms to prevent kinking while the proximal segment maintains its shape for structural integrity.
3Adaptability or versatility
If a guide wire is used to help navigate the catheter through tortuous vessels, then the catheter can reach difficult locations, but the procedure time increases and the clot may be disrupted
Solution Approach 1:
The catheter is designed with inherent gradient flexibility that enables it to self-navigate through tortuous vessels and branch points without requiring external assistance from guide wires. The varying flexibility along its length allows the catheter to automatically adapt to vessel geometry, eliminating the need for additional navigation tools and reducing procedure time.
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 through tortuous vessels, avoid getting stuck, and maintain access to clots, thereby improving the efficiency and success rate of thrombectomy procedures.
Implementation Method 1
a distensible segment (50) located between the proximal segment (36) and the distal segment (64) that is configured to undergo a conformational change when a linear force in a distal direction is applied to the catheter (10) and, in turn, a linear force in a proximal direction is applied to the catheter open distal end (12)
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.