Rotary Knife Blade with Mainspring and Latch for Surgical Stapling

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Solution Overview

Problem

Existing rotary knife cutting systems for surgical stapling devices face challenges in cutting through wayward staples and tough tissues during anastomosis procedures, leading to potential improper connections between tubular tissue sections.

Innovation Solution

A rotary cutting system with a mainspring-driven knife blade and a latch mechanism that imparts rotary motion to the knife blade, allowing it to effectively slice through staples and tissues, while preventing premature rotation until staples are properly placed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a linear stapling device is used to cut across tubular tissue, then the tissue can be stapled and cut, but the cut edge resembles a duckbill which requires additional circular stapling and core removal steps

Engineering Contradiction:
Improveanastomosis formation efficiencyVSAvoidsurgical procedure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the cutting function and core removal function into a single rotary knife blade that performs both operations during one rotational motion. The knife blade cuts through the duckbill tissue while simultaneously coring out the stapled section, eliminating the need for separate cutting and core removal steps in the anastomosis procedure.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a circular knife blade is advanced through stapled tissue, then the duckbilled sections can be cut, but wayward staples may obstruct the blade path and prevent proper anastomosis

Engineering Contradiction:
Improveanastomosis success rateVSAvoidinterference from wayward staples
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a rotary knife blade that rotates in a circular path rather than moving linearly. This rotational motion allows the blade to slice through wayward staples that may be positioned in the tissue, as the curved cutting path can navigate around or through misplaced staples more effectively than a straight blade, ensuring complete core removal and successful anastomosis.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If the knife blade is driven by a mainspring, then rotary motion can be imparted to cut through tough tissue, but the blade may rotate prematurely before staples are properly placed

Engineering Contradiction:
Improvecutting capability through tough tissueVSAvoidpremature rotation prevention
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent incorporates a latch mechanism that prevents the mainspring from releasing and driving the knife blade until the stapling operation is complete. The latch is positioned to engage with the knife blade assembly and block rotational motion. Only after the linear stapler has fired and secured the tissue does the latch release, allowing the mainspring to impart rotary motion to the knife blade. This preliminary restraining action ensures proper stapling occurs before cutting begins.

Inventive Principle:
Principle #9Preliminary anti-action

4Reliability

If a latch mechanism is added to prevent premature rotation, then reliable operation can be ensured, but the device complexity increases

Engineering Contradiction:
Improveoperation sequencing controlVSAvoidlatch mechanism components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The latch mechanism is integrated into the existing knife blade assembly rather than being a separate, independent component system. The latch utilizes parts of the knife blade structure itself and coordinates with the stapler firing mechanism, combining the sequencing control function with the existing cutting mechanism. This integration minimizes the number of additional components needed while still providing reliable prevention of premature blade rotation.

Inventive Principle:
Principle #5Merging (Combining)

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

Ensures a proper anastomosis by efficiently cutting through wayward staples and tough tissues, ensuring a secure connection between tubular tissue sections without residual connections.

Implementation Method 1

a mainspring for imparting motion to the knife blade relative to the support base. The mainspring is a length of material spiral coiled upon itself and expandable from a wound condition storing energy to an expanded condition releasing energy such that the mainspring imparts a rotary motion to the knife blade relative to the support base

Methodology Applied
Scientific EffectElastic potential energy storage and release: Spring

Data Source

PatentEP2030578B1Rotary knife cutting systems
Publication Date: 2010.11.03 COVIDIEN LP
  • EP2030578B1 patent drawingFigure 1
  • EP2030578B1 patent drawingFigure 2~3
  • EP2030578B1 patent drawingFigure 4~5

AI summary

There are disclosed rotary cutting systems for use with circular surgical stapling devices. The rotary cutting systems generally include a circular knife blade and a mainspring for imparting rotary motion to the circular knife blade. A latch mechanism is provided to maintain the knife blade on a linear travel path during a first predetermined distance and to release the circular knife blade for rotation due to the bias of the mainspring along a second predetermine distance. The circular knife blade may be rotated by the mainspring itself or, in an alternative embodiment, may be driven by frictional engagement with a rotational hammer.