Fluid Gel Optical Gap for Catheter Force Sensing
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Solution Overview
Problem
Existing catheter-based diagnostic and treatment systems for organs or vessels lack precise force measurement capabilities, leading to imprecise positioning and potential tissue damage due to inadequate contact force sensing, which can result in ineffective treatments or unintended punctures.
Innovation Solution
A force sensing catheter tip with a displacement feature and optical fibers, where a fluid, such as silicone gel, fills the gap between the fibers to inhibit contamination and maintain consistent optical characteristics, enabling accurate force measurement using a Fabry-Pérot interferometer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual feedback or impedance measurements are used to determine catheter positioning, then the system complexity is reduced, but the measurement precision and positioning accuracy deteriorate
Solution Approach 1:
The patent replaces manual feedback mechanisms and impedance measurements with an optical measurement system using a Fabry-Pérot interferometer. This optical system provides precise force and position measurements by detecting changes in the optical path length between two fibers, eliminating the need for complex mechanical feedback while achieving superior measurement precision.
Solution Approach 2:
The patent introduces an optical intermediary system (the fluid-filled gap between optical fibers) that mediates the measurement process. The fluid acts as an optical medium that transmits light between the fibers while being sensitive to pressure changes, enabling precise force measurement without direct mechanical contact or complex electronic sensors.
2Device complexity
If expandable baskets or hooks are used to stabilize the catheter distal extremity, then the device complexity is reduced, but the measurement precision and contact force sensing capability deteriorate
Solution Approach 1:
The patent replaces mechanical stabilization structures like expandable baskets or hooks with an optical sensing system. The Fabry-Pérot interferometer provides contact force sensing capability by measuring displacement of the catheter tip through optical path length changes, eliminating the need for mechanical stabilization while achieving superior measurement precision.
Solution Approach 2:
The optical fluid gap serves as an intermediary that enables contact force sensing without mechanical contact. The fluid transmits pressure changes from catheter tip displacement to the optical fibers, allowing precise force measurement while maintaining a simple, flexible catheter structure without complex mechanical stabilization components.
3Reliability
If the end effector contacts the tissue wall with excessive force, then the treatment effectiveness is improved, but harmful factors increase due to tissue puncture risk
Solution Approach 1:
The patent implements real-time feedback through the optical interferometer system that continuously monitors contact force between the catheter and tissue. This feedback enables closed-loop control of the end effector positioning, allowing the system to maintain optimal treatment force while automatically detecting and preventing excessive force that could cause tissue puncture, thereby improving treatment effectiveness while reducing harmful factors.
Solution Approach 2:
The patent applies preliminary anti-action by using the optical sensing system to detect approaching excessive force before tissue puncture occurs. The system provides early warning and automatic correction capability, preventing harmful effects before they manifest, while still allowing sufficient contact force for effective treatment.
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 system provides precise force measurement, reducing errors in tissue ablation and enhancing treatment efficacy by accurately determining the force applied to the tissue, thus minimizing the risk of under or over-ablation and tissue puncture.
Implementation Method 1
The second optical fiber can be positioned at a distance from the first optical fiber and can be configured to move with respect to the first optical fiber according to a displacement of the distal portion of the tip.
Implementation Method 2
the fluid can have a refraction index of 1, 1.3, or any value therebetween
Data Source
AI summary
An ablation catheter including a tip coupled to a distal end of a shaft. The tip can include a displacement feature between a proximal portion and a distal portion of the tip. The distal portion can be configured to move with respect to the proximal portion based on the displacement feature. A first optical fiber can be coupled to the proximal portion. A second optical fiber coupled to the distal portion and optically aligned with the first optical fiber. The second optical fiber can be positioned at a distance from the first optical fiber and can be configured to move with respect to the first optical fiber according to a displacement of the distal portion of the tip. A fluid can be located between the first optical fiber and the second optical fiber.