Electrostrictive Catheter Segments for Magnetic Navigation Control
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Solution Overview
Problem
Current magnetic navigation techniques for medical devices face challenges such as insufficient torque to overcome resistance, device prolapse, buckling at vessel branches, and difficulty in maintaining contact with moving heart walls, particularly in areas where the distal end is not perpendicular to the tissue, limiting precise control and effectiveness.
Innovation Solution
Integration of electrostrictive elements with magnetic navigation systems, allowing for voltage-controlled bending or stiffening of medical device segments to enhance navigation, including the use of electrostrictive materials that change dimension with applied voltage to improve orientation and positioning of medical devices within the body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If magnetic steering techniques are used to control catheter orientation, then the physician can remain outside the operating room x-ray field, but there is a lag between the applied magnetic field and the actual orientation of the distal end of the medical device
Solution Approach 1:
The medical device is divided into multiple segments with independent electrostrictive actuators at each segment. This allows localized bending control at the distal end, enabling faster and more precise orientation adjustments without waiting for the entire device to respond to magnetic field changes, thereby reducing the orientation lag.
Solution Approach 2:
Electrostrictive actuators provide dynamic, real-time control of the distal end orientation by rapidly changing shape in response to electrical signals. This dynamic actuation capability allows the distal end to immediately adjust its orientation without the lag inherent in magnetic steering alone, while the physician maintains control from outside the x-ray field.
2Extent of automation
If magnetic steering is used to navigate the device, then computer-assisted control is achieved, but the applied torque may not be sufficient to overcome resistance in areas of rapid blood flow
Solution Approach 1:
The patent combines magnetic steering with electrostrictive actuation to create a hybrid control system. The electrostrictive actuators generate additional torque at the distal end by changing shape in response to electrical signals, supplementing the magnetic torque and providing sufficient force to overcome resistance in areas of rapid blood flow while maintaining computer-assisted control.
3Speed
If proximal device advancement is used, then the device can be pushed forward, but device prolapse or buckling may occur at vessel branches
Solution Approach 1:
Electrostrictive actuators dynamically adjust the stiffness and shape of device segments in real-time. When approaching vessel branches, the actuators can stiffen the device to prevent prolapse and buckling during advancement, then flex the device to navigate branches, enabling fast and safe device progression through complex vasculature.
Solution Approach 2:
The electrostrictive actuators change the physical parameters (stiffness, shape) of device segments by applying electrical voltage. This allows the device to transition between flexible and stiff states as needed, preventing prolapse and buckling during advancement while enabling navigation through vessel branches.
4Ease of operation
If guide catheter is inserted to coronary ostium, then access is achieved, but resistance to advancement may cause the guide catheter to become dislodged
Solution Approach 1:
Electrostrictive actuators provide dynamic control of the distal end, allowing the guide catheter to maintain its position at the coronary ostium by actively compensating for forces during interventional device advancement. The actuators can stiffen the distal end to resist dislodgment forces while maintaining precise positioning.
5Extent of automation
If magnetic navigation is used for interventional device advancement, then navigation control is achieved, but it is not possible to precisely control the magnetic field applied at the ostium when navigating the distal tip beyond the guide catheter distal tip
Solution Approach 1:
Electrostrictive actuators serve as an intermediary control mechanism that allows precise local control of the distal end without requiring precise control of the magnetic field at the ostium. The actuators respond to electrical signals from the proximal end, enabling independent control of the distal tip position and orientation even when the magnetic field cannot be precisely controlled at the ostium.
6Ease of operation
If current magnetic navigation technologies are used in endocardial applications, then navigation is achieved, but it is difficult to maintain contact between the interventional device distal end and the moving heart wall, particularly upon oblique or glancing approaches
Solution Approach 1:
Electrostrictive actuators enable dynamic adjustment of the distal end shape and orientation in real-time. During contact with the moving heart wall, the actuators can actively adjust the distal end configuration to maintain reliable contact even during oblique or glancing approaches, compensating for heart wall motion and improving procedural reliability.
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 combination enables more precise and effective navigation by minimizing deflection and dislodgment, improving access to target areas, and reducing the size and cost of magnetic source magnets, thereby enhancing the performance of magnetic navigation systems.
Implementation Method 1
electrostrictive behavior... at least one electrostrictive element disposed on or near its distal end that is adapted to cause the distal end to bend in a given direction
Implementation Method 2
at least one magnetically responsive element on the distal end, which may be oriented in the direction of an externally applied magnetic field
Data Source
AI summary
An apparatus and method for interventional navigation within a subject's body is provided in which a medical device having at least one electrostrictive element is adapted to cause the distal end of the medical device to bend in a given direction for improving navigation. The medical device may further comprise at least one magnetically responsive element on the distal end, which may be oriented in the approximate direction of a magnetic field that is applied to the subjects body. At least one method for navigating a medical device though a subject's body is provided, by changing the direction of an applied magnetic field to align a magnetically responsive element on the distal end for orienting the distal end, and by applying a voltage to at least one electrostrictive element disposed in the distal portion of the device for causing the distal end to change orientation from that achieved by application of the magnetic field alone.