Surgical Stapler Articulation Load Control for Cable Tension Spikes
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Solution Overview
Problem
Endoscopic surgical instruments experience force spikes during surgical procedures, which can strain the drivetrain and affect the precision and reliability of the surgical stapler.
Innovation Solution
The surgical instrument incorporates a motor, sensors, and a controller to regulate articulation loads, featuring an articulation joint with a cable articulation subsystem, a knife firing subsystem, and a roll subsystem, allowing for precise articulation and stapling operations while minimizing force spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If articulation joints are included to enable end effector positioning, then positioning capability is improved, but force spikes are generated that strain the drivetrain
Solution Approach 1:
The controller receives feedback from sensors about the state of the articulation cables and motors, and automatically adjusts motor commands to maintain cable tensions within safe thresholds. This closed-loop control prevents force spikes from propagating through the drivetrain while preserving full articulation capability.
Solution Approach 2:
The system proactively monitors articulation cable tensions before excessive forces can damage the drivetrain. By detecting tension thresholds in advance and preemptively adjusting motor commands, the system prevents force spikes rather than reacting to them after occurrence.
2Reliability
If motors and sensors are added to regulate articulation loads, then reliability is improved, but device complexity increases
Solution Approach 1:
The existing motors that control articulation are made multi-functional: they both position the end effector and simultaneously regulate articulation cable tensions. The same motor actuators serve dual purposes, eliminating the need for separate tensioning mechanisms and reducing overall system complexity.
Solution Approach 2:
The system uses its own existing sensors and motors to monitor and regulate its own articulation loads. The controller leverages data from articulation sensors and commands to the articulation motors to self-regulate cable tensions, eliminating the need for external monitoring or adjustment mechanisms.
3Reliability
If cable tensions are reduced to prevent force spikes, then drivetrain reliability is improved, but articulation precision may be affected
Solution Approach 1:
The system dynamically adjusts motor commands in real-time to maintain cable tensions within safe thresholds while preserving the ability to achieve precise articulation positions. The controller continuously adapts its control strategy based on current tension levels and desired end effector positioning, ensuring both reliability and precision.
Data Source
AI summary
A method for performing an electrosurgical procedure using an electrosurgical instrument. The method includes selecting a desired pose of an end effector with respect to a shaft assembly and conducting a surgical procedure on a patient tissue via the end effector that causes tensions to be exerted on a plurality of articulation cables for the desired pose of the end effector. The method further includes obtaining, by a controller via a plurality of sensors, the tensions that are exerted on the plurality of articulation cables during the surgical procedure and determining whether the tensions exceed a first predetermined tension threshold and in response to determining that the tensions exceed the first predetermined tension threshold, operating at least one motor of the plurality of motors to reduce the tensions until the tensions are at or below the first predetermined tension threshold.