Rotatable Catheter Cutting Element with Cam-Driven Oscillation
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Solution Overview
Problem
Current atherectomy catheters face challenges in effectively removing atheromatous deposits from blood vessels, as they often require complex mechanisms and may not efficiently manage cutting depth and tissue collection, leading to incomplete removal and potential vessel damage.
Innovation Solution
A catheter design featuring a rotatable shaft with a cutting element that moves between a stored and cutting position, utilizing a cam mechanism for longitudinal and rotational movement, coupled with a biasing member for retraction, and an imaging transducer for precise visualization, allowing for controlled cutting and material collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotating burr or cutter is used to remove atheromatous deposits, then material removal capability is improved, but control over cutting depth and precision is reduced
Solution Approach 1:
The cutting element is designed to oscillate between a retracted position and an extended cutting position rather than rotating continuously. This dynamic positioning allows precise control of cutting depth while maintaining effective material removal capability during the extended phase.
Solution Approach 2:
The cutting element performs periodic oscillation between retracted and extended positions. During the extended phase, material is removed; during the retracted phase, the cutting element is protected and position is reset. This periodic action enables both effective cutting and precise depth control.
2Manufacturing precision
If a complex mechanism is used to manage cutting depth and tissue collection, then cutting precision is improved, but device complexity increases
Solution Approach 1:
The drive shaft integrates multiple functions: it drives the cutting element oscillation, controls its extension and retraction, and coordinates with the tissue collection system. This merging of functions reduces the number of separate components while maintaining precise cutting depth control.
Solution Approach 2:
The cutting element serves multiple purposes: it cuts atheromatous material when extended, and it is retracted to protect the vessel wall and allow catheter navigation. The same component performs both cutting and protection functions, simplifying the overall device architecture.
3Productivity
If the cutting element remains exposed during navigation, then cutting readiness is improved, but vessel damage risk increases
Solution Approach 1:
The cutting element dynamically transitions between an extended ready-to-cut position and a retracted protected position. During catheter navigation, the cutting element remains retracted to avoid damaging the vessel wall, and extends only when positioned at the treatment site ready to cut.
Solution Approach 2:
The cutting element is prepared in advance by extending it only after the catheter is properly positioned at the treatment site. This preliminary positioning ensures the cutting element is exposed and ready for cutting only when needed, minimizing the time it is exposed and thus reducing vessel damage risk.
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 enhances the efficiency of plaque removal by ensuring precise cutting and collection, reducing vessel damage, and improving blood flow restoration while allowing for adjustable cutting depth and enhanced visualization during the procedure.
Implementation Method 1
a cam follower secured to the rotatable shaft adjacent the proximal end of the rotatable shaft; and a handle attached to the tubular body adjacent the proximal end of the tubular body, the handle including a motor, and a cylindrical cam coupled to the motor and to the cam follower
Implementation Method 2
a biasing member coupled to the rotatable shaft and configured to bias the cutting element toward the stored position
Data Source
Figure 1A~1B
Figure 1C~2A
Figure 2B~3
AI summary
A catheter having a tubular body and a rotatable shaft disposed within a lumen of the tubular body. A cutting element is coupled to the rotatable shaft, the cutting element having a cutting edge, the cutting element and rotatable shaft being longitudinally moveable within the tubular body between a stored position in which the cutting element is parallel a longitudinal axis of the tubular body and a cutting position in which the cutting element is deflected between the proximal and distal ends of the tubular body to extend beyond an outer diameter of the tubular body. The cutting element is configured to cut material from the wall of a vessel at a treatment site as the catheter is pushed distally through the treatment site. The catheter includes a collection chamber positioned proximally of the cutting window.