Surgical Stapler Rotatable Knob Trigger Mechanism

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Solution Overview

Problem

Existing open linear staplers require excessive force to fire staples and lack an integrated cutting mechanism, limiting their usability and precision in surgical procedures.

Innovation Solution

A surgical stapler design featuring a pivotable trigger linked to an end effector with a staple cartridge and anvil, and an integrated knife, where a rotatable knob reduces the force required to eject staples and cut tissue, ensuring low actuation force and precise staple placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional firing mechanism is used, then the stapler can fire staples, but a large amount of force is required which limits the number of surgeons that can use the device

Engineering Contradiction:

Improveforce required to fire staplesVSAvoidusability by surgeons with varying strength

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces the conventional high-force mechanical firing mechanism with a low-profile trigger mechanism that utilizes mechanical advantage through linkages and cam surfaces. The trigger system converts small manual forces into the necessary stapling force through a sequence of mechanical movements including trigger pivot, linkage rotation, and cam surface interaction, thereby reducing the direct force requirement on the surgeon while maintaining reliable staple firing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a conventional stapler design is used, then staples can be fired, but no cutting means or knife is available after staples have been fired

Engineering Contradiction:

Improvefunctional capabilities after staplingVSAvoidintegration of multiple functions

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates a knife mechanism into the existing stapler body, merging the cutting function with the stapling function. The knife is positioned within the anvil assembly and is actuated through the same trigger mechanism that fires the staples. This allows the surgeon to perform both stapling and cutting operations with a single device without requiring separate instruments, thereby increasing versatility while managing device complexity through shared mechanical components.

Inventive Principle:

Principle #5Merging (Combining)

3Manufacturing precision

If tissue cannot be grasped and secured prior to firing, then the device is simpler, but if a surgeon slips firing the device, staples may be misplaced from their intended position

Engineering Contradiction:

Improveprecision of staple placementVSAvoidtissue securing mechanism

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent incorporates tissue securing features in the form of jaw surfaces with friction surfaces and engagement features that allow the surgeon to grasp and secure the tissue between the anvil and cartridge before firing. The jaw closure mechanism provides preliminary tissue positioning and securing, ensuring proper alignment and preventing slippage during the firing process, thereby improving staple placement precision while adding controlled complexity through the jaw closure system.

Inventive Principle:

Principle #10Preliminary action

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 stapler allows for efficient and precise placement of staples with reduced manual force, incorporating a cutting mechanism that divides tissue with minimal effort, enhancing surgical efficiency and reducing the risk of misplacement.

Implementation Method 1

an actuator for ejecting the plurality of staples from the cartridge towards the anvil. The actuator includes a rotatable knob mounted onto the distal end of the handle, such that progressive rotation of the knob in a predetermined direction progressively ejects the staples

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

The distal end of the trigger being pivotably attached to the handle between the handle's distal and proximal end

Methodology Applied

Scientific EffectLever: Lever

Data Source

PatentUS7431190B2Linear stapler with improved firing mechanism

Publication Date: 2008.10.07 ETHICON ENDO SURGERY INC

AI summary

A surgical stapler comprising including an elongated handle portion having a longitudinal axis extending between a distal end and a proximal end. The stapler includes an end effector disposed at the distal end of the handle having a staple cartridge housing, and an anvil. The end effector has an open position wherein the staple cartridge and the anvil are spaced apart, and a closed position wherein the staple cartridge and anvil are closely adjacent to each other. The stapler also includes an elongated trigger. The distal end of the trigger being pivotably attached to the handle between the handle's distal and proximal end. The trigger has an open position wherein the proximal end of the trigger is spaced apart from the handle, and a closed position wherein the proximal end of the trigger is closely adjacent the handle. The trigger is linked to the end effector such that moving the trigger from its open to its closed position moves the end effector from its open to its closed position. The stapler also includes an actuator for ejecting the plurality of staples from the cartridge towards the anvil. The actuator includes a rotatable knob mounted onto the distal end of the handle, such that progressive rotation of the knob in a predetermined direction progressively ejects the staples.