Sheath Electromagnetic Sensor Configuration for Navigation Accuracy
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Solution Overview
Problem
Conventional navigation systems for medical procedures, such as catheter ablation, face inaccuracies in determining the location of a steerable and deflectable sheath due to reliance on impedance-based navigation, which lacks precision compared to electromagnetic navigation for catheters, and requires additional programming to correct for errors.
Innovation Solution
Incorporating two or more electromagnetic sensors at the distal region and a third sensor at the proximal region of the sheath, along with sensors on the catheter, to provide six degrees of freedom for accurate location determination using electromagnetic navigation, eliminating the need for additional programming to correct for sheath-catheter location errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance-based navigation is used to determine sheath location, then the system can track the sheath without x-ray exposure, but the measurement precision and accuracy are insufficient compared to electromagnetic navigation
Solution Approach 1:
The patent combines electromagnetic sensors with the sheath structure, merging the tracking function directly into the sheath. This allows the sheath to be tracked using electromagnetic navigation with the same precision as catheters, eliminating the need for separate impedance-based tracking systems and achieving high measurement precision without proportionally increasing overall system complexity
Solution Approach 2:
The patent replaces impedance-based navigation (electrical field method) with electromagnetic navigation (magnetic field method) for sheath tracking. This substitution provides superior measurement precision and accuracy for sheath location determination, as electromagnetic fields offer better signal stability and measurement resolution compared to impedance-based methods
2Measurement precision
If electromagnetic sensors are added to the sheath, then location accuracy improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent nests electromagnetic sensors within the sheath structure, placing them in a hollow or integrated configuration. This nesting approach allows the sensors to be incorporated into the sheath without significantly altering the external sheath geometry or requiring separate manufacturing processes, thereby maintaining ease of manufacture while achieving high location accuracy
Solution Approach 2:
The sheath design incorporates electromagnetic sensors that serve multiple functions: tracking the sheath's position and orientation in 3D space, and potentially serving as reference points for relative position calculations with the catheter. This multi-functionality reduces the need for additional separate components, simplifying the overall manufacturing process while maintaining high measurement precision
3Reliability
If multiple electromagnetic sensors are placed on the sheath, then six degrees of freedom for location determination are achieved, but the device complexity increases
Solution Approach 1:
The patent segments the electromagnetic sensing function across multiple discrete sensors positioned at specific locations on the sheath (e.g., proximal and distal regions). This segmentation allows each sensor to independently measure local electromagnetic fields, and through coordinate transformation and integration, provides complete 6-degree-of-freedom location and orientation information, enhancing reliability without requiring a single complex sensor system
Solution Approach 2:
The patent uses the known geometric relationship between multiple electromagnetic sensors on the sheath as an intermediary to derive the sheath's 6-degree-of-freedom pose. By measuring positions of multiple sensors and applying rigid-body transformation mathematics, the system calculates the sheath's location and orientation with high reliability, avoiding the need for a single complex 6-DOF sensor while managing device complexity through computational methods
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 approach enables precise and accurate determination of both catheter and sheath locations in 3D space, enhancing navigation accuracy and reducing errors, while avoiding the limitations of impedance-based navigation.
Implementation Method 1
at least one electromagnetic sensor, disposed at the catheter, configured to generate electrical signals indicative of a location of the catheter in response to receiving at least one magnetic field
Implementation Method 2
a first electromagnetic sensor and a second electromagnetic sensor, disposed at a first region of the sheath, each configured to generate electrical signals indicative of a location of the sheath in response to receiving the at least one magnetic field
Data Source
AI summary
A medical tool for use with an electromagnetic navigation system includes a catheter configured to be navigated within patient anatomy and at least one electromagnetic sensor, disposed at the catheter, configured to generate electrical signals indicative of a location of the catheter in response to receiving at least one magnetic field. The medical tool also includes a sheath configured to receive the catheter, a first electromagnetic sensor and a second electromagnetic sensor, disposed at a first region of the sheath, each configured to generate electrical signals indicative of a location of the sheath in response to receiving the at least one magnetic field and a third electromagnetic sensor, disposed at a second region of the sheath spaced from the first region, configured to generate electrical signals indicative of a location of the sheath in response to receiving the at least one magnetic field.