Steerable Catheter Force Sensor Pulling Wire Integration
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Solution Overview
Problem
Steerable catheters used in Minimal Invasive Systems, such as cochlear implant electrodes, face challenges in reaching small anatomical structures due to increased thickness caused by force sensors and their connecting wires, limiting access to the deepest parts of the cochlea.
Innovation Solution
The catheter design incorporates a force sensor where the pulling wire serves as both the connecting wire and the pulling wire, anchored by connectors, allowing for a smaller diameter and reduced wire count, utilizing optical or electrical force sensors like fibre Bragg sensors or Shape Memory Alloy (SMA) wires, which are integrated within the catheter shaft, enabling precise bending and sensitivity without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force sensor and its connecting wires are added to the catheter, then the catheter can detect contact forces and prevent damage, but the catheter diameter increases and it cannot reach the deepest parts of the cochlea
Solution Approach 1:
The connecting wire to the force sensor is merged with the pulling wire used for steering the catheter. This integration eliminates the need for separate connecting wires, reducing the overall catheter diameter while maintaining both steering functionality and force sensing capability. The pulling wire serves dual purposes: mechanical steering and electrical connection to the sensor.
Solution Approach 2:
The pulling wire is given multiple functions: it acts as both the mechanical element for steering the catheter tip and the electrical connection wire to the force sensor. This multi-functionality reduces the number of separate components needed, allowing the catheter to maintain a smaller diameter while still providing both steering control and force detection capabilities.
2Measurement precision
If separate connecting wires and force sensor are used, then force detection is achieved, but the catheter structure becomes more complex and larger in diameter
Solution Approach 1:
The force sensor and its connecting wire are merged into a single integrated component. The pulling wire itself serves as the connection medium, eliminating the need for separate connecting wires and reducing structural complexity. This integration maintains accurate force detection while simplifying the overall catheter architecture.
Solution Approach 2:
The pulling wire performs multiple functions simultaneously: it provides mechanical tension for steering the catheter tip and serves as the electrical conduit for the force sensor. This multi-functionality reduces the total wire count and simplifies the catheter structure while maintaining both steering precision and force measurement capability.
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 design allows for a significantly smaller catheter that can be inserted through very small openings, maintaining sensitivity and functionality, enabling deeper cochlear access while allowing for the transport of medical devices like cochlear implant electrodes.
Implementation Method 1
A possibility is the use of an optical force sensor, like a fibre Bragg sensor or Fabry-Perot sensor as in the prior art
Implementation Method 2
The pulling wires are electrically conducting and at the distal part two pulling wires are electrically connected by a Shape Memory Alloy (SMA) wire that can serve as the force sensor
Data Source
AI summary
The invention deals with a steerable catheter system. Such systems are used in Minimal Invasive Systems (MIS) for getting access to difficult to reach places, like body cavities or blood vessels in for instance the human anatomy. The steerable catheter comprises a polymer shaft with a bending portion that comprises a pulling wire mechanically anchored at a distal part of the bending portion, where the shaft is provided with a central lumen and a force sensor at the distal part. According to the invention the pulling wire is the connecting wire to the force sensor and the pulling wire is mechanically anchored by a connector between the pulling wire and the force sensor.