Stapling Device Locking Member Gap Control
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Solution Overview
Problem
Surgical stapling devices face challenges in maintaining proper alignment and minimizing deflection of the staple cartridge and anvil assembly during firing, which can lead to inconsistent staple formation and tissue gap maintenance.
Innovation Solution
A tool assembly featuring a locking member with a threaded outer surface that engages a threaded bore in the anvil, coupled with a sled and tether system, which rotates to approximate the distal portions of the anvil and cartridge assembly, maintaining a consistent tissue gap through threaded engagement and biasing mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the staple cartridge and anvil assembly are movable between open and clamped positions during firing, then the stapling device can perform stapling and cutting operations, but the forces during firing cause deflection of the staple cartridge and anvil assembly outwardly away from each other, leading to misalignment and inconsistent staple formation
Solution Approach 1:
The locking member is rotated to the locked position before firing to pre-establish the tissue gap and lock the distal portions of the anvil and cartridge assembly in the correct position. This preliminary action ensures that the gap is maintained during firing, preventing deflection-induced misalignment and ensuring consistent staple formation.
Solution Approach 2:
The locking member acts as an intermediary mechanism between the sled and the distal portions of the anvil and cartridge assembly. By rotating the locking member, the sled's movement is converted into a locking action that maintains the tissue gap, mediating the forces during firing to prevent outward deflection.
2Force
If the distal portions of the anvil and cartridge assembly are allowed to deflect outwardly during firing, then the forces are distributed more naturally, but the alignment between staple pockets and deforming pockets is compromised, resulting in improper staple formation
Solution Approach 1:
The locking member applies a counteracting force to the outward deflection tendency during firing. By locking the distal portions in place before firing, the system preemptively counteracts the deflection forces, maintaining alignment between staple pockets and deforming pockets while still allowing natural force distribution.
3Manufacturing precision
If a locking mechanism is introduced to maintain the tissue gap and prevent deflection, then staple formation consistency is improved, but the device complexity increases with additional components and operations
Solution Approach 1:
The locking mechanism is merged with the existing sled and trigger assembly. The locking member is rotatably supported on the cartridge assembly and operably coupled to the sled, integrating the locking function into the existing firing mechanism rather than adding a separate, independent locking system.
Solution Approach 2:
The locking member serves multiple functions: it maintains the tissue gap, prevents outward deflection during firing, and ensures proper alignment between staple pockets and deforming pockets. This multi-functionality reduces the need for additional separate components, offsetting the complexity increase with functional consolidation.
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 maintains a predetermined tissue gap between the anvil and cartridge assembly, preventing over-compression and ensuring consistent staple formation, thereby improving the precision and reliability of the stapling process.
Implementation Method 1
The locking member has a threaded outer surface configured for threaded engagement with the threaded inner surface of the anvil
Implementation Method 2
a biasing member configured to apply a force to the locking member
Data Source
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AI summary
A tool assembly includes an anvil and a cartridge assembly pivotally coupled to one another. A locking member is rotatably supported on a distal portion of the cartridge assembly and positioned for receipt in a bore defined in a distal portion of the anvil. The locking member is operably coupled to a sled for advancing staples from the cartridge assembly. Advancement of the sled rotates the locking member relative to the bore to approximate the distal portions of the anvil and cartridge assembly.