Electromechanical Surgical Stapler Control for Constant-Force Ejection
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Solution Overview
Problem
Existing powered surgical staplers experience slower staple ejection rates compared to manual staplers, and there is a need for powered devices that can match or exceed the ejection speed of manual devices while maintaining consistent force application.
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 controlled staple ejection and tissue cutting, with features like pulse-width-modulated motor control signals and a sensor to measure force imparted on the drive beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If motors are used to actuate the end effector in powered surgical devices, then automation is improved, but staple ejection speed deteriorates compared to manual devices
Solution Approach 1:
The motor controller dynamically adjusts the motor speed and torque output during the stapling cycle. The system transitions from high-speed operation during initial jaw closure to controlled lower-speed operation during staple ejection, optimizing both automation performance and ejection speed to match manual device performance
Solution Approach 2:
The system changes operational parameters (speed, torque, power delivery) throughout the stapling cycle based on real-time feedback from force sensors. This allows the motorized device to achieve rapid automation while maintaining staple ejection speeds comparable to manual devices by adjusting power delivery characteristics
2Productivity
If motor speed is increased to improve staple ejection speed, then productivity is improved, but force control precision deteriorates
Solution Approach 1:
Force sensors provide real-time feedback on the forces applied during jaw closure and staple ejection. The motor controller uses this feedback to maintain precise force control even at higher speeds, ensuring consistent staple formation and tissue clamping while achieving improved productivity
Solution Approach 2:
The system dynamically adjusts motor parameters based on real-time force measurements, allowing high-speed operation during phases where speed is critical while maintaining precise force control during phases where accuracy is paramount, such as staple ejection and tissue clamping
3Reliability
If force on drive beam is maintained constant to improve reliability, then manufacturing precision is improved, but device complexity increases due to control systems
Solution Approach 1:
Real-time force feedback from sensors during jaw closure and staple ejection enables the motor controller to maintain constant force on the drive beam, ensuring reliable and consistent surgical outcomes. The feedback loop continuously monitors and adjusts motor output to compensate for variations in tissue properties and mechanical resistance
Solution Approach 2:
The patent replaces purely mechanical force transmission systems with an electromechanical system where a motor and controller substitute for manual operation. This substitution enables automated constant force control through electronic feedback, improving reliability while the complexity is managed through integrated control algorithms
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 and tissue cutting by maintaining constant force on the drive beam, improving the ejection speed and performance of powered surgical staplers to match or exceed manual staplers.
Implementation Method 1
a motor coupled to the power source
Implementation Method 2
a sensor configured to measure a force imparted on the drive beam
Implementation Method 3
The motor control signals may be pulse-width-modulated
Data Source
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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.