Powered Surgical Stapler Force Control for Faster Staple Ejection
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Solution Overview
Problem
Powered surgical staplers exhibit slower staple ejection rates compared to manual staplers, necessitating a need for improved motor control to match the speed and efficiency of manual devices.
Innovation Solution
A surgical device with a handle assembly, adapter assembly, and end effector that includes a motor controller using a proportional-integral-derivative (PID) controller to maintain constant force on a drive beam, enabling faster staple ejection by pulse-width-modulated motor control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a motor is used to actuate the end effector in a powered surgical device, then the device can be operated with automated control, but the staple ejection rate becomes slower compared to manual staplers
Solution Approach 1:
The motor controller dynamically adjusts the motor speed and torque in real-time during the stapling cycle. The controller modifies operational parameters based on the phase of operation (approximation, firing, ejection) to optimize performance. This dynamic control allows the motor to deliver high power when needed for rapid staple ejection while maintaining automated operation throughout the procedure.
Solution Approach 2:
The system changes motor operational parameters (speed, torque, power) during different phases of the stapling cycle. The motor controller implements parameter modulation to achieve high-speed staple ejection comparable to manual devices, while maintaining the benefits of automated control. Parameters are adjusted based on feedback from sensors and pre-programmed sequences.
2Productivity
If the motor operates at high speed to increase staple ejection rate, then productivity improves, but control precision and force consistency deteriorate
Solution Approach 1:
The motor controller incorporates feedback mechanisms that monitor motor performance and operational parameters in real-time. This feedback allows the controller to make real-time adjustments to maintain precise control over the drive beam force and position, even during high-speed operation. The feedback loop ensures that force consistency is maintained while achieving high staple ejection rates.
Solution Approach 2:
The system employs dynamic control strategies that adjust motor parameters during the stapling cycle. During high-speed ejection phases, the controller modulates power delivery to maintain force consistency. The dynamic adjustment of operational parameters allows the system to achieve both high productivity and precise force control simultaneously.
3Device complexity
If the motor is controlled with simple on/off switching, then device complexity is reduced, but the ability to maintain constant force during drive beam movement deteriorates
Solution Approach 1:
The motor controller implements parameter modulation to maintain constant force on the drive beam throughout the approximation and ejection cycle. By adjusting voltage, current, and pulse width parameters dynamically, the controller ensures reliable and consistent force application. This parameter control approach maintains reliability while managing device complexity through integrated control circuitry.
Solution Approach 2:
The control system incorporates feedback mechanisms that monitor drive beam position and force application. This feedback enables the motor controller to make real-time adjustments to maintain constant force, improving reliability without requiring overly complex mechanical force transmission mechanisms. The feedback loop compensates for variations in tissue resistance and mechanical friction.
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 achieves consistent and efficient staple ejection rates comparable to manual staplers, enhancing the performance of powered surgical staplers.
Implementation Method 1
The motor control signals may be pulse-width-modulated
Data Source
AI summary
A surgical device includes an end effector having a pair of opposing jaw members and a drive beam movable longitudinally through the pair of opposing jaw members thereby approximating the pair of opposing jaw members relative to each other. The device also includes an adapter assembly configured to selectively couple to the end effector. The adapter assembly includes an actuation assembly configured to mechanically engage the drive beam and to move the drive beam longitudinally. The device also includes a handle assembly configured to selectively couple to the adapter assembly. The handle assembly includes: a power source, a motor coupled to the power source, a sensor configured to measure a force imparted on the drive beam, and a motor controller configured to control the motor to maintain constant force on the drive beam based on the force measured by the sensor during longitudinal movement of the drive beam approximating the pair of opposing jaw members closer relative to each other.