Surgical Stapling Tissue Gap Adjustment Mechanism
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Solution Overview
Problem
Current surgical stapling apparatuses for circular anastomosis lack a convenient and efficient mechanism for adjusting the minimum tissue gap between the anvil head and the staple holding component, which is crucial for accommodating varying tissue thickness and properties.
Innovation Solution
The surgical stapling apparatus incorporates a tissue gap adjustment mechanism that utilizes a set screw and an asymmetrical washer to adjust the longitudinal position of the screw stop, allowing for discrete adjustments of the minimum tissue gap between the anvil assembly and the stapling assembly through a range of pre-determined interval steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tissue gap adjustment mechanism is added to allow adjustment of the minimum tissue gap, then the adaptability to different tissue thicknesses is improved, but the device complexity increases
Solution Approach 1:
The adjustment mechanism is nested within the existing stapling apparatus structure. The set screw is positioned within the anvil assembly, and the asymmetrical washer is integrated into the longitudinal positioning system of the screw stop, allowing the adjustment functionality to be embedded without significantly increasing external device complexity
Solution Approach 2:
The asymmetrical washer with its non-circular configuration enables self-aligning and self-locking functionality. When the set screw is tightened against the screw stop, the asymmetrical shape of the washer prevents rotation and maintains the adjusted position automatically, reducing the need for additional locking mechanisms
2Ease of operation
If a set screw and asymmetrical washer mechanism is used for adjustment, then the ease of operation is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The asymmetrical washer features a non-circular configuration with specific geometric asymmetry that enables directional insertion and prevents over-rotation. This asymmetrical design provides tactile feedback to the operator during adjustment, allowing for precise positioning through feel rather than requiring high-precision manufacturing tolerances
Solution Approach 2:
The set screw and washer assembly is pre-configured with predetermined interval steps built into the asymmetrical washer geometry. This preliminary configuration of adjustment steps allows the operator to select from pre-determined gap settings without requiring complex measurement or calculation during the surgical procedure
Data Source
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AI summary
A surgical stapling apparatus (10) includes a tissue gap adjustment mechanism (260) having a stop member (250), an asymmetrical polygonal washer (264), and a set screw (262). The stop member (250) is supported on a drive screw (220), includes first and second flanges (255a, 255b), and defines a transverse slot (254) between the flanges (255a, 255b). The stop member (250) sets a minimum tissue gap. The washer (264) defines an eccentrically positioned aperture (268) and includes a plurality of pairs of opposed flat sides (269a-269h). The set screw (262) is configured to fix the stop member (250) relative to the drive screw (220). The washer (264) is selectively rotatable about the set screw (262) to position a selected pair of sides (269a-269h) between and in engagement with the flanges (255a, 255b) to set the position of the aperture (268) of the washer (264) relative to the transverse slot (254), thereby setting the stop member (250) relative to the drive screw (220) and defining the minimum tissue gap.