Steerable Catheter Tip Segmentation for Torque and Stiffness
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Solution Overview
Problem
Current steerable catheters face challenges in navigating the tortuous anatomy of the body's vasculature due to issues with tip stiffness, torque transmission, and difficulty in maintaining stable contact with myocardial walls, particularly in reaching around obstacles and requiring adjustable tip lengths.
Innovation Solution
A steerable catheter design featuring a deflectable tip assembly with a coaxially disposed inner body and support structure, an actuator mechanism for linear movement transfer, and a catheter sheath for protection, utilizing materials like Nitinol for enhanced stiffness and flexibility, allowing for precise tip deflection and rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stylette is used to provide lateral stiffness to the catheter tip, then the tip can be deflected and rotated, but the lateral stiffness becomes dependent on the stylette which cannot transmit torque effectively
Solution Approach 1:
The catheter is divided into distinct functional segments: a flexible catheter body for navigation, a separate inner body with struts for structural support, and a stylette for tip shaping. This segmentation allows each component to perform its specialized function without compromising the others - the struts provide torque transmission while the stylette provides lateral stiffness independently.
Solution Approach 2:
The inner body with struts acts as an intermediary between the catheter body and the stylette. It transfers and transmits torque from the operator's manipulation at the proximal end to the distal tip, while the stylette independently provides lateral stiffness without needing to transmit torque.
2Adaptability or versatility
If the catheter tip is made very soft to allow bending and navigation, then the catheter can navigate tortuous vasculature, but the electrode cannot be held firmly against the myocardial wall
Solution Approach 1:
Different parts of the catheter have different mechanical properties: the catheter body is flexible for navigation through tortuous vasculature, while the tip region with struts and stylette provides enhanced lateral stiffness and torque transmission capability to hold the electrode firmly against the myocardial wall when needed.
3Ease of operation
If puller wires are used to deflect the tip, then the tip can be steered, but the catheter body is subject to the same deflection as the tip
Solution Approach 1:
The catheter is segmented into a catheter body and a separate inner body with struts. The puller wires are contained within the inner body structure, allowing tip deflection without causing the entire catheter body to deflect, thereby maintaining catheter body stability during steering operations.
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
The design enables improved navigation and stable contact within the vasculature by providing enhanced lateral stiffness and torque transmission, facilitating access to challenging anatomical sites while maintaining safety and flexibility during use.
Implementation Method 1
enhanced lateral stiffness and torque transmission
Implementation Method 2
utilizing materials like Nitinol for enhanced stiffness and flexibility
Data Source
AI summary
This invention relates to devices for navigating passageways in a body, and in particular, to a steerable catheter that can be used to navigate the tortuous anatomy of a body's vasculature. In one embodiment of the invention the deflectable catheter comprises an inner catheter body having a first strut spine member and a cantilevered second strut tang member. An outer catheter body is cooperatively associated with the second strut tang member and an actuator is cooperatively associated with the first strut spine member. The actuator is slideably engaged within the outer catheter body.