Atherectomy Burr Torque Feedback for Speed and Stuck Prevention
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Solution Overview
Problem
Current atherectomy devices face challenges in effectively removing occlusive material from body lumens without damaging surrounding vessel walls or previously implanted stents, and in managing torque issues during the procedure.
Innovation Solution
The development of an atherectomy system with a drive mechanism and controller that regulates operation based on torque feedback, including a Proportional Integral Derivative (PID) controller to manage torque and speed, and a user interface for alerting users to torque increases, along with features to handle stuck burrs and unwind energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the atherectomy burr is advanced through the occlusion to remove material, then the occlusion is cleared and blood flow is restored, but torque increases and may cause the burr to become stuck or damage surrounding vessel walls
Solution Approach 1:
The system continuously monitors torque at the atherectomy burr and feeds this information back to the controller. When torque exceeds a threshold, the controller automatically responds by reducing motor speed or reversing rotation, preventing the burr from becoming stuck and protecting surrounding vessel walls from damage.
Solution Approach 2:
The drive mechanism dynamically adjusts motor speed based on real-time torque conditions. The controller modulates the motor speed to maintain optimal cutting performance while preventing excessive torque that could cause the burr to become embedded in the vessel wall or occlusive material.
2Object-affected harmful factors
If the motor speed is reduced to prevent torque-related damage, then vessel wall damage is minimized, but occlusion removal efficiency decreases
Solution Approach 1:
The system employs periodic reversals of motor rotation when torque thresholds are exceeded. This periodic action allows the burr to be withdrawn slightly, reducing torque and preventing damage, then resumed to continue cutting, maintaining overall removal efficiency while protecting the vessel wall.
Solution Approach 2:
The controller applies partial speed reduction or temporary reversals rather than complete shutdown when torque increases are detected. This partial action maintains sufficient cutting performance to continue removing occlusion while briefly reducing torque to prevent vessel wall damage.
3Strength
If the drive mechanism provides high torque to remove tough occlusive material, then cutting effectiveness is improved, but the risk of the burr becoming stuck increases
Solution Approach 1:
The system proactively monitors torque and implements preventive measures by reducing speed or reversing rotation before the burr becomes completely stuck. This beforehand cushioning prevents the burr from embedding too deeply into the vessel wall, making extraction easier and avoiding complicated retrieval procedures.
4Reliability
If the controller automatically responds to torque increases by reducing speed, then procedural safety is improved, but the complexity of the control system increases
Solution Approach 1:
The control system operates autonomously by automatically monitoring torque and adjusting motor speed without requiring manual intervention. The system serves itself by detecting torque increases and independently implementing corrective actions, improving safety while keeping the user interface simple.
Data Source
AI summary
An atherectomy system includes a drive mechanism that is adapted to rotatably actuate an atherectomy burr and a controller that is adapted to regulate operation of the drive mechanism. In some cases, the drive mechanism includes a drive cable that is coupled with the atherectomy burr and a drive motor that is adapted to rotate the drive cable. The controller is adapted to receive an indication of an increase in torque experienced at the atherectomy burr and is further adapted to, in response, regulate operation of the drive mechanism such that the increase in torque results in a noticeable reduction in speed of the drive mechanism such that a user of the atherectomy system notices the reduction in speed and is alerted to the increase in torque.