Medical Balloon Actuator for Marker Alignment
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Solution Overview
Problem
Angioplasty balloons face challenges in precise positioning of the working surface due to misalignment of marker bands on the catheter shaft, which can lead to geographic misplacement during procedures, and the balloon's tendency to pancake upon deflation, causing inaccurate inflation perception.
Innovation Solution
Incorporating a mechanical actuator, such as springs, that moves between defined positions to align the working surface with radiopaque markers and prevent undesirable folding, ensuring precise positioning and controlled inflation/deflation of the balloon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If marker bands are attached to the catheter shaft to indicate the working surface position, then the physician can locate the balloon position, but misalignment occurs between the markers and the actual working surface due to tolerance stack-ups, balloon growth, and shaft flexing
Solution Approach 1:
The actuator is designed to move dynamically between a first position (when the balloon is deflated) and a second position (when the balloon is inflated). This movement compensates for the balloon's longitudinal growth and shaft flexing, maintaining continuous alignment between the radiopaque marker and the working surface throughout the inflation process, thereby resolving the misalignment issue caused by static marker placement
Solution Approach 2:
The actuator serves as an intermediary mechanical element that connects the balloon to the catheter shaft. By positioning the radiopaque marker on the actuator rather than directly on the shaft, the system creates a flexible linkage that accommodates dimensional changes and flexing while maintaining accurate positioning reference, thus mediating between the rigid shaft and the compliant balloon
2Ease of operation
If the balloon is designed to be compact for low profile during delivery, then the balloon can be easily tracked and pushed, but the balloon tends to pancake upon deflation, causing inaccurate perception of inflation status
Solution Approach 1:
The actuator incorporates a radiopaque marker that provides visual feedback through fluoroscopy. When the actuator is in the second position, the marker aligns with the working surface, indicating proper inflation. When in the first position, the marker's position relative to the working surface indicates deflation or partial inflation, preventing the loss of visual information about balloon status even when the balloon is collapsed
3Stress or pressure
If the balloon is inflated to high pressure to treat calcified plaque, then the blockage can be resolved, but the balloon requires complex technology to maintain high pressure without sacrificing profile
Solution Approach 1:
The balloon is segmented into different functional zones: a working surface portion with predetermined radius of curvature for plaque treatment, and tapered portions at the ends. The actuator is positioned to align specifically with the working surface portion. This segmentation allows the balloon to be inflated to high pressures locally at the working surface while maintaining a lower overall profile through the tapered sections, reducing the complexity required for high-pressure maintenance
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
Enhances procedural precision and efficiency by maintaining accurate alignment of the working surface with markers and preventing pancaking, allowing for reliable balloon deployment and repositioning without increasing complexity or cost.
Implementation Method 1
an actuator, such as a spring, that moves in response to inflation and deflation of the balloon
Implementation Method 2
a radiopaque marker band M... to provide better visibility under X-ray or other form of radiography
Data Source
Figure 1~2
Figure 3~3a
Figure 4
AI summary
A medical balloon may be provided with an actuator. In one embodiment a balloon catheter includes a shaft extending in a longitudinal direction, said shaft having a proximal end and a distal end, and supporting at least one radiopaque identifier. An inflatable balloon supported along the distal end of the shaft, the balloon when inflated including a working surface. An actuator is provided for aligning at least one end of the working surface with the at least one radiopaque identifier. In another embodiment, the actuator assists with preferential folding. Related methods are also disclosed.