Releasable Knife in Surgical Stapler Reload Assembly
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Solution Overview
Problem
Circular surgical stapling devices pose a risk to clinicians as the cutting edge of the annular knife can inadvertently be exposed during tissue removal, potentially causing injury.
Innovation Solution
A surgical stapling device with a knife carrier that releasably couples to an annular knife, which is embedded in a cut ring of the anvil assembly after firing, ensuring the cutting edge is shielded by separating from the carrier when the anvil assembly moves from a clamped to an open position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the knife is permanently fixed to the knife carrier, then the cutting edge remains exposed and accessible for tissue removal, but the risk of accidental injury to the clinician increases
Solution Approach 1:
The knife is designed with a resilient engagement mechanism that allows it to move dynamically between fixed and released states. During tissue removal, the knife remains engaged with the carrier for stability. After use, the knife can be released by applying force to the anvil assembly, transitioning from a fixed to a released state to prevent accidental injury.
Solution Approach 2:
The knife and knife carrier are designed as separable components rather than a permanent fixed assembly. The resilient fingers provide a controlled engagement interface that allows the knife to be released from the carrier after use, segmenting the device into separable parts for safety.
2Object-affected harmful factors
If the knife is released from the knife carrier after firing, then the cutting edge is shielded and safety is improved, but the complexity of the engagement mechanism increases
Solution Approach 1:
The resilient fingers automatically engage with the knife's inverted proximal portion during assembly, and the release mechanism is self-actuating through the movement of the anvil assembly. The engagement and disengagement occur through the natural operational movements of the device without requiring additional complex control systems.
Solution Approach 2:
The knife release mechanism is integrated with the anvil assembly structure. The resilient fingers are formed as part of the knife carrier, and the release action is combined with the normal opening motion of the anvil assembly, merging multiple functions into a unified mechanism.
3Object-affected harmful factors
If the knife is made resiliently engageable with the knife carrier, then the knife can be released for safety, but the manufacturing precision requirements increase
Solution Approach 1:
The resilient fingers are designed as flexible elastic elements that can deform to accommodate the knife during engagement and return to their original position to maintain the engaged state. This flexibility compensates for minor manufacturing variations and allows for reliable engagement without requiring extremely tight tolerances.
Solution Approach 2:
The engagement mechanism utilizes the elastic properties of the resilient fingers, changing the physical state from rigid to flexible during engagement. The resilient fingers can deform elastically to accommodate the knife and maintain a secure engaged state, reducing the need for high manufacturing precision.
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 solution effectively shields the cutting edge of the knife from the clinician, preventing accidental exposure and ensuring safer handling of the device post-procedure.
Implementation Method 1
the first engagement portion is defined by a plurality of resilient fingers formed on the distal portion of the knife carrier
Data Source
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AI summary
A surgical stapling device includes an anvil assembly and a reload assembly that includes a knife and a knife carrier. The knife is releasably coupled to the knife carrier and is embedded in a cut ring of the anvil assembly when the stapling device is fired. The knife is separable from the knife carrier upon application of a predetermined force on the knife. The predetermined force is applied to the knife after the stapling device is fired by moving the anvil assembly in relation to the reload assembly from a clamped position to an open position.