Tissue-Removing Catheter With Adjustable Jogged Portion
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Solution Overview
Problem
Existing vascular catheters face challenges in accessing and removing atheromatous materials from small, tortuous body lumens, such as peripheral arteries, in a controlled and efficient manner, particularly when dealing with fibrous and calcified plaque.
Innovation Solution
A tissue-removing catheter with a jogged portion that applies an urge force against the body lumen wall, featuring a tissue-removing element like a cutter, and an adjustable urging mechanism to enhance the catheter's bending stiffness and control the force applied, allowing for effective removal of occlusive materials from various body lumens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the catheter body is made more flexible to access small tortuous body lumens, then the ability to navigate complex vascular paths is improved, but the ability to apply sufficient cutting force to fibrous and calcified plaque deteriorates
Solution Approach 1:
The catheter body is divided into multiple segments with different stiffness characteristics: a flexible proximal portion for navigation and a stiffer distal portion for cutting. This segmentation allows each section to perform its optimal function - the proximal flexible section navigates tortuous paths while the distal stiffer section delivers cutting force to plaque.
Solution Approach 2:
Different portions of the catheter body are assigned different mechanical properties - the proximal portion is made more flexible to accommodate navigation through small tortuous lumens, while the distal portion is made stiffer to provide the necessary cutting force. This local differentiation of mechanical properties resolves the contradiction between flexibility and force application.
2Force
If the catheter body is made stiffer to apply sufficient cutting force, then the ability to cut fibrous and calcified plaque is improved, but the ability to navigate small tortuous body lumens deteriorates
Solution Approach 1:
The catheter is segmented into proximal and distal portions with different stiffness levels, allowing the distal cutting section to be stiffer for effective plaque removal while the proximal section remains flexible for navigation through tortuous vasculature.
Solution Approach 2:
The catheter body exhibits local quality variations in mechanical stiffness - the distal portion has higher stiffness for cutting while the proximal portion has lower stiffness for navigation, resolving the contradiction between force application and adaptability.
3Productivity
If the urge force applied by the jogged portion is increased to improve tissue removal effectiveness, then the cutting performance is improved, but the risk of damaging the body lumen wall increases
Solution Approach 1:
The urging mechanism allows dynamic adjustment of the urge force applied by the jogged portion. The operator can modulate the force in real-time based on tissue characteristics and procedural progress, enabling effective cutting while minimizing damage risk through controlled, adjustable force application.
Solution Approach 2:
The urging mechanism enables change in the urge force parameter applied to the tissue. By adjusting this parameter, the system can optimize cutting effectiveness while staying below the threshold that would cause damage to the body lumen wall.
4Manufacturing precision
If the bending stiffness of the jogged portion is adjusted to control the urge force, then the precision of force application is improved, but the device complexity increases
Solution Approach 1:
The urging mechanism provides dynamic control over the bending stiffness and urge force of the jogged portion. This allows precise adjustment of force application characteristics while maintaining a relatively simple mechanical implementation through springs, shape memory alloys, or other actuation mechanisms.
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 controlled and efficient removal of tissue and occlusive materials from small, tortuous body lumens, including those with fibrous and calcified deposits, by adjusting the urge force and bending stiffness, facilitating better access and treatment of a broader range of vascular conditions.
Implementation Method 1
An urging mechanism selectively applies a compressive load to the catheter body to adjust the bending stiffness of the jogged portion
Data Source
AI summary
A tissue-removing catheter includes an elongate catheter body. The catheter body has a jogged portion that applies an urge force against a body lumen wall and urges a portion of the catheter body toward a portion of the body lumen wall. A tissue-removing element removes tissue from the body lumen during the cutting operation. The tissue-removing element is located generally adjacent the portion of the catheter body that is urged toward the body lumen wall by the logged portion. An urging mechanism selectively applies a compressive load to the catheter body to adjust the bending stiffness of the jogged portion and the urge force applied by the jogged portion.