Rotational Atherectomy Device with Offset Counterweights
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Solution Overview
Problem
Current rotational atherectomy devices are limited in their ability to open arteries to a diameter larger than the resting diameter of the abrasive section, often requiring multiple burrs and lacking control over the diameter of the artery abraded, due to fixed burr sizes and inefficient orbital motion.
Innovation Solution
A high-speed rotational atherectomy device with a flexible, elongated drive shaft featuring an abrasive section with counterweights offset from the longitudinal axis, allowing for orbital motion and enabling the abrasive section to open stenotic lesions to a diameter substantially larger than its resting diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a fixed-size abrasive burr is used, then the device structure is simple, but the artery cannot be opened to a diameter larger than the burr's resting diameter
Solution Approach 1:
The burr is designed with a flexible structure that allows it to dynamically change its effective diameter during rotation. The counterweights create orbital motion that enables the burr to sweep a larger diameter path than its resting diameter, allowing the artery to be opened to a greater diameter without requiring multiple fixed-size burrs.
Solution Approach 2:
Counterweights are attached to the drive shaft at a location offset from the burr's center of mass. When rotated, these counterweights generate centrifugal force that stimulates orbital motion of the burr, causing it to follow an elliptical path and sweep a larger diameter area during high-speed rotation.
2Volume of moving object
If an eccentric burr design is used to achieve orbital motion, then the artery can be opened to a larger diameter, but heat and centrifugal force increase excessively
Solution Approach 1:
Instead of using an eccentric burr design that generates excessive heat and centrifugal force, the invention uses counterweights mounted on the drive shaft. These counterweights generate the necessary orbital motion through centrifugal force while being positioned to create controlled, manageable forces that do not excessively heat the artery or create harmful centrifugal effects at the burr-tissue interface.
Solution Approach 2:
The system separates the orbital motion generation function from the abrasive function. The counterweights handle the orbital motion generation, while the burr focuses solely on abrasion. This segmentation allows the burr to be optimized for cutting without the heat-generating eccentric design.
3Volume of moving object
If multiple burr sizes are used to open the artery to desired diameter, then the desired diameter can be achieved, but the procedure time and complexity increase
Solution Approach 1:
A single burr design with counterweights performs multiple functions: it can open arteries to various diameters by adjusting rotational speed and utilizing the orbital motion envelope. This universal design replaces the need for multiple specialized burrs of different sizes, reducing procedural time and device complexity while achieving the same clinical outcomes.
4Productivity
If the abrasive section is rotated at high speeds, then tissue removal efficiency increases, but control over the abraded diameter becomes difficult
Solution Approach 1:
The system incorporates feedback mechanisms to monitor and control the orbital motion of the burr during high-speed rotation. Sensors detect the burr's position and motion characteristics, allowing real-time adjustment of rotational parameters to maintain precise control over the abraded diameter while preserving high tissue removal efficiency.
Solution Approach 2:
The flexible burr structure dynamically adapts to the artery wall during high-speed rotation, maintaining optimal contact and control. The counterweight-driven orbital motion creates a predictable elliptical path that enhances tissue removal efficiency while the flexibility provides passive feedback for diameter control.
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
The device effectively opens stenotic lesions to a larger diameter than previous technologies, using counterweights to stimulate orbital motion and maintain control over the abrasive section during high-speed rotation, potentially reducing the need for multiple burrs and improving procedural efficacy.
Implementation Method 1
each counterweight has its center of mass offset from the longitudinal axis of the drive shaft to stimulate orbital motion by the abrasive section
Implementation Method 2
a concentrically shaped ellipsoidal burr covered with an abrasive abrading material such as diamond particles
Data Source
AI summary
The invention provides a rotational atherectomy device having a flexible, elongated, rotatable drive shaft with an abrasive section comprising an enlarged diameter section of the drive shaft or, alternatively, a solid abrasive crown which may be attached to the drive shaft. The device further comprises a proximal and/or a distal counterweight attached to the drive shaft, spaced from the abrasive section wherein each counterweight has its center of mass offset from the longitudinal axis of the drive shaft to stimulate orbital motion by the abrasive section. When placed within an artery against stenotic tissue and rotated at sufficiently high speeds (e.g., in the range of about 20,000 rpm to about 200,000 rpm) the orbiting nature of the abrasive section causes such section to rotate as to open the stenotic lesion to a diameter substantially larger than the resting outer diameter of the abrasive section.