Atherectomy Motor PWM Feedback Near Torque and Speed Limits

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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 providing real-time feedback to operators regarding motor performance parameters.

Innovation Solution

An atherectomy device system with a control system that uses high frequency pulse width modulation (PWM) drive signals to regulate a drive motor and provide tactile and audible feedback when motor performance parameters approach or exceed predetermined thresholds, ensuring safe operation and effective occlusion removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a drive motor is used to rotate the atherectomy burr, then effective occlusion removal is achieved, but real-time feedback on motor performance parameters is insufficient

Engineering Contradiction:
Improvemotor performance parameter monitoringVSAvoidreal-time feedback to operator
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The control system continuously monitors motor performance parameters (torque, speed, current) and provides real-time feedback to the operator through tactile signals. When parameters approach predefined thresholds, the system generates haptic feedback via the handle, enabling the operator to immediately adjust operation and prevent damage to the burr or surrounding tissue.

Inventive Principle:
Principle #23Feedback

2Productivity

If high torque is applied to remove occlusive material, then effective occlusion removal is achieved, but risk of damage to surrounding vessel walls or stents increases

Engineering Contradiction:
Improveocclusion removal efficiencyVSAvoiddamage to surrounding tissue
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control system monitors motor current and torque in real-time, comparing these parameters against predefined safety thresholds. When thresholds are approached, tactile feedback warnings are provided to the operator, enabling immediate adjustment of applied force to prevent damage to surrounding vessel walls or stents while maintaining effective occlusion removal.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system establishes predefined safety thresholds for motor parameters before operation begins. These thresholds act as preventive boundaries that, when approached, trigger warning signals to the operator, allowing corrective action to be taken before damage occurs to the burr or surrounding tissue.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If motor speed is increased to improve occlusion removal, then productivity increases, but motor performance limits may be exceeded

Engineering Contradiction:
Improveocclusion removal rateVSAvoidmotor performance within limits
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control system continuously monitors motor speed and compares it against predefined performance limits. When the speed approaches these limits, tactile feedback signals are provided to the operator through the handle, enabling immediate adjustment to prevent exceeding motor performance capabilities and ensuring reliable operation throughout the procedure.

Inventive Principle:
Principle #23Feedback

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 system effectively maintains safe torque and speed ranges at the atherectomy burr, providing operators with intuitive feedback to prevent damage and ensure efficient occlusion removal, thereby overcoming limitations of previous devices.

Implementation Method 1

The control system is adapted to provide the drive motor with a high frequency pulse width modulation (PWM) drive signal in order to operate the drive motor and monitor a motor performance parameter

Methodology Applied
Scientific EffectPulse width modulation:

Implementation Method 2

the control system adds a low frequency PWM signal to the high frequency PWM drive signal, thereby causing the drive motor to produce a tactile signal that signals to the user that the motor performance parameter is approaching the limit of the performance range

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3758627B1Atherectomy motor control system with tactile feedback
Publication Date: 2023.09.13 BOSTON SCIENTIFIC SCIMED INC
  • EP3758627B1 patent drawingFigure 1
  • EP3758627B1 patent drawingFigure 2
  • EP3758627B1 patent drawingFigure 3

AI summary

An atherectomy system includes a handle and a drive motor that is adapted to rotate a drive cable extending through the handle and operably coupled to an atherectomy burr. A control system is adapted to regulate operation of the drive motor, including providing the drive motor with a high frequency pulse width modulation (PWM) drive signal in order to operate the drive motor. The control system monitors a motor performance parameter such as motor speed or motor torque, and when the motor performance parameter approaches a limit of a performance range, the control system adds a low frequency PWM signal to the high frequency PWM drive signal, thereby causing the drive motor to produce a tactile signal that signals to the user that the motor performance parameter is approaching the limit of the performance range.