Trocar Latch Prevents Back-Driving in Circular Surgical Stapler
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Solution Overview
Problem
Current surgical stapling instruments face challenges in maintaining a consistent gap distance during end-to-end anastomosis procedures, leading to potential deviations in tissue stapling and severing accuracy.
Innovation Solution
The circular stapling surgical instrument incorporates a trocar latch assembly and ratcheting mechanisms to prevent unwanted translation of the trocar, ensuring a consistent gap distance by locking the trocar in place during the stapling and severing process, thereby maintaining precise tissue alignment and closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the trocar is allowed to translate freely during stapling, then the device complexity is reduced, but the gap distance consistency and tissue alignment precision deteriorate
Solution Approach 1:
The latch assembly is configured to prevent back-driving of the circular stapler before the stapling operation is complete. The pawl engages with the gear teeth to create a mechanical lock that opposes any reverse motion of the trocar, thereby maintaining the predetermined gap distance and preventing tissue alignment errors during the stapling process.
Solution Approach 2:
The system establishes a predetermined gap distance between the anvil and stapler head assembly before the stapling operation begins. The latch mechanism is pre-configured to engage at this specific gap distance, ensuring that the correct spacing is maintained throughout the procedure without requiring continuous adjustment or monitoring.
2Reliability
If the latch assembly is engaged to prevent back-driving, then the reliability of stapling accuracy is improved, but the device complexity increases
Solution Approach 1:
The latch assembly operates automatically based on the position of the circular stapler relative to the anvil. When the stapler is advanced to the correct position, the pawl automatically engages with the gear teeth through the action of a spring, creating a self-actuating mechanism that maintains gap distance without requiring external control or additional actuators.
Solution Approach 2:
The gear mechanism serves as an intermediary between the linear motion of the trocar and the rotational engagement of the latch. The gear teeth translate the axial position of the stapler into rotational positions that correspond to the engagement points of the pawl, providing a mechanical interface that simplifies the latch activation while maintaining precision.
3Manufacturing precision
If the trocar translation is restricted by the latch, then the tissue alignment precision is improved, but the ease of operation deteriorates
Solution Approach 1:
The latch mechanism transitions from an unlocked to a locked state dynamically during the stapling procedure. The spring-loaded pawl allows free movement of the trocar during initial positioning and tissue clamping, then automatically engages to prevent back-driving when the stapling force is applied, adapting its constraint level to the procedural stage without requiring manual intervention.
Data Source
AI summary
An apparatus includes a handle assembly having a body, a shaft assembly having an outer tubular member extending distally from the body, an end effector, an anvil, and a trocar latch assembly. The end effector includes a staple deck fixed relative to the outer tubular member, a staple driver that can actuate relative to the staple deck between an unfired position and a fired position, and a trocar that can actuate relative to the staple deck and the staple driver, the anvil can couple with trocar to move relative to the staple deck to define a gap distance. The trocar latch assembly includes a locking body that can actuate between an unlocked configuration and a locked configuration in response to the staple driver actuating between the unfired position and the fired position. The locking body can selective fix the trocar relative to the staple deck in the locked position.