Surgical Anvil Welded Cap Design for Flexure Resistance

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Solution Overview

Problem

Current surgical stapling systems face challenges in efficiently stapling and cutting tissue due to stress concentrations and flexure issues in the anvil and firing member, leading to increased firing force requirements and potential misalignment during the stapling process.

Innovation Solution

The design incorporates a surgical stapling anvil with an anvil cap that is welded and mechanically interlocked to the anvil body, enhancing stiffness and resistance to flexure forces, and a firing member with specific cam surfaces and projections to manage tissue engagement and staple formation effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the anvil is designed with a single-piece construction, then manufacturing is simpler, but stress concentrations and flexure issues occur leading to increased firing force requirements

Engineering Contradiction:
Improveanvil manufacturing simplicityVSAvoidfiring force requirement
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The anvil is divided into two separate members: an anvil body and an anvil cap. These members are joined together through welding and mechanical interlocking features. This segmentation allows each component to be optimized independently for stress distribution and flexibility, reducing stress concentrations and the overall firing force requirement while maintaining manufacturing feasibility through modular assembly.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the anvil members are rigidly connected, then structural stability is improved, but misalignment occurs during stapling due to inability to accommodate flexure

Engineering Contradiction:
Improveanvil structural stabilityVSAvoidstaple alignment precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The connection between the anvil body and anvil cap incorporates dynamic characteristics through mechanical interlocking features that allow controlled relative movement. This enables the anvil to accommodate flexure and maintain alignment during the stapling process, preventing misalignment while preserving structural stability through the interlocked configuration.

Inventive Principle:
Principle #15Dynamics

3Strength

If the anvil cap is welded to the anvil body, then resistance to flexure forces is enhanced, but device complexity increases due to additional joining mechanisms

Engineering Contradiction:
Improveresistance to flexure forcesVSAvoidanvil construction complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The anvil cap and anvil body are connected through a combination of welding and mechanical interlocking features. This merging of joining methods creates a unified structure with enhanced resistance to flexure forces. The welded connection provides strong structural bonding while the mechanical interlocking features add reinforcement and alignment capabilities, achieving high strength without excessive complexity through integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3639758B1Surgical anvil arrangements
Publication Date: 2021.04.28 ETHICON INC
  • EP3639758B1 patent drawingFigure 1
  • EP3639758B1 patent drawingFigure 2
  • EP3639758B1 patent drawingFigure 3

AI summary

A surgical stapling anvil for use with a surgical instrument is disclosed. The anvil comprises an anvil body comprising a tissue-facing surface and a longitudinal cavity. The longitudinal cavity comprises a first cavity portion configured to receive at least a portion of a cutting edge of a firing member of the surgical instrument therethrough, a second cavity portion configured to receive an anvil-engaging portion of the firing member therethrough, and a third cavity portion comprising a first angular surface which flares outward relative to the second cavity portion. The anvil further comprises an anvil cap comprising a first section positioned within a portion of the second cavity portion and a second section positioned within the third cavity portion, wherein the second section comprises a second angular surface corresponding to the first angular surface, and wherein the first angular surface and the second angular surface are welded together.