Balloon Catheter Nitinol Shaft Shape Memory Biasing
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Solution Overview
Problem
Balloon catheters face challenges in maintaining a longitudinally extended state after therapy delivery, which complicates their withdrawal due to radial expansion and potential bunching, necessitating a mechanism to bias the balloon assembly effectively.
Innovation Solution
A medical device with a catheter shaft and a balloon assembly featuring a biasing member, such as a spring or coiled fluid supply tube, that biases the balloon to a longitudinally extended state, allowing for radial expansion during therapy and subsequent return to the extended state upon fluid exhaustion for easier withdrawal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the balloon is allowed to radially expand after therapy delivery, then the balloon can maintain contact with the treatment site, but the balloon becomes difficult to withdraw due to bunching and radial expansion
Solution Approach 1:
The patent replaces the traditional mechanical biasing mechanism with a shape memory alloy (Nitinol) catheter shaft that uses thermal-mechanical properties to automatically return the balloon to its original configuration. The Nitinol material exhibits superelasticity and shape memory effects, allowing the balloon to radially expand during therapy and then automatically return to its extended state without complex mechanical components, thus solving the withdrawal difficulty while maintaining therapeutic effectiveness.
2Ease of operation
If a biasing mechanism is added to maintain the balloon in an extended state, then the balloon can be easily withdrawn, but the device complexity increases
Solution Approach 1:
The patent implements a self-service biasing mechanism where the Nitinol catheter shaft automatically returns the balloon to its extended configuration through its inherent shape memory properties. The system uses the body's temperature to trigger the phase transformation of Nitinol, causing the balloon to self-bias to its original shape without requiring external mechanical components, springs, or complex actuation systems. This eliminates the need for additional biasing mechanisms while achieving easy withdrawal.
3Reliability
If the balloon remains in a radially expanded state, then the therapy can be effectively delivered, but the catheter cannot be smoothly navigated or withdrawn
Solution Approach 1:
The patent creates a dynamic system where the balloon's radial dimension can change on demand. During navigation and withdrawal, the balloon maintains its extended configuration for smooth movement. During therapy delivery, the balloon radially expands to contact the treatment site. The Nitinol catheter shaft dynamically adjusts the balloon's configuration based on thermal conditions, allowing the system to switch between navigation mode and therapy mode efficiently, thus improving both navigation efficiency and therapy effectiveness.
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
Enables efficient delivery and retrieval of the balloon catheter by maintaining the balloon in a longitudinally extended configuration, facilitating smooth navigation and therapy application while preventing radial expansion issues during withdrawal.
Implementation Method 1
A biasing member can be disposed in the chamber of the balloon assembly and may be connected to the inner tubular member and the outer tubular member. The biasing member may be configured to bias the balloon assembly to a longitudinally extended state. In some cases, the biasing member may be a spring.
Data Source
AI summary
Methods and devices for biasing a balloon catheter are disclosed. In one example, a medical device may include a catheter shaft and a balloon assembly coupled to a distal region of the catheter shaft. The balloon assembly can define a chamber configured to be inflated and deflated using a fluid supplied from the catheter shaft. A biasing member may be positioned in the chamber of the balloon assembly and may be configured to bias the balloon assembly to a longitudinally extended state without obstructing an exhaust lumen of the catheter shaft. In some cases, the biasing member may be a spring. In other cases, the biasing member may be a coiled portion of a fluid supply line.