Surgical Stapler Adapter Shear Pin Torque Protection
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Solution Overview
Problem
Powered surgical stapling instruments face damage to the adapter and handle assemblies due to high forces experienced during the stapling process, particularly when the sled jams or locks, leading to potential damage and misfire issues.
Innovation Solution
An adapter with a shear pin mechanism that connects the proximal and distal drive shafts, allowing the proximal drive shaft to rotate independently when a predetermined torque is applied, thereby preventing damage by fracturing and separating the connection between the drive shafts when excessive force is encountered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive assembly rotates the drive screw to advance the sled for stapling, then the stapling function is achieved, but high force may damage the adapter assembly and/or handle assembly when the sled reaches the end of travel or jams
Solution Approach 1:
A shear pin is introduced as an intermediary component between the proximal drive shaft and distal drive shaft. The shear pin normally transmits torque to enable stapling function, but is designed to fracture when excessive force is applied, thereby protecting the adapter assembly and handle assembly from damage while maintaining the stapling function during normal operation
Solution Approach 2:
The shear pin is designed as a sacrificial, disposable component that is intentionally made weaker than the drive shafts and adapter assembly. When excessive force occurs, the shear pin fractures instead of allowing damage to more expensive and critical components. The shear pin can be replaced to restore full functionality
2Object-affected harmful factors
If the shear pin fractures to prevent damage, then protection from high force is achieved, but the connection between drive shafts is lost
Solution Approach 1:
The system is designed to discard the fractured shear pin and recover by replacing it with a new one. The adapter assembly and drive shafts are designed to be reusable after shear pin replacement, while the shear pin itself is a consumable component that is discarded after fracture and recovered through replacement to restore the drive shaft connection
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 shear pin mechanism effectively prevents damage to the adapter and handle assemblies by allowing the proximal drive shaft to continue rotating independently of the distal drive shaft when high forces are applied, reducing the risk of misfires and maintaining the integrity of the surgical stapling instrument.
Implementation Method 1
The shear pin is configured to fracture to permit rotation of the proximal drive shaft independent of rotation of the distal drive shaft when a predetermined torque is applied to the distal drive shaft
Data Source
AI summary
An adapter for releasably connecting a loading unit to a handle assembly includes a proximal drive shaft, a distal drive shaft, and a shear pin connecting the proximal drive shaft to the distal drive shaft. The proximal drive shaft includes proximal and distal portions. The proximal portion of the proximal drive shaft is configured for releasable connection to the handle assembly. The distal drive shaft includes proximal and distal portions. The distal portion of the distal drive shaft being configured for releasable connection to the loading unit. The shear pin is configured to rotationally fix the proximal drive shaft to the distal drive shaft and is configured to fracture to permit rotation of the proximal drive shaft independent of rotation of the distal drive shaft when a predetermined torque is applied to the distal drive shaft.