Surgical Stapling Instrument Geared Return Mechanism

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Solution Overview

Problem

Existing surgical staplers face challenges in maintaining the position of the end effector relative to the shaft assembly, leading to shear forces on soft tissue and difficulties in retracting the cutting member due to significant force requirements and premature return of the cutting member.

Innovation Solution

A surgical instrument with a locking mechanism that fixes the relative position between the shaft assembly and end effector, a closure system that prevents articulation after closure, and a firing drive with a flexible band and brake to control the movement of the cutting member and staple driver.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a return spring is used to retract the cutting member, then the cutting member can be retracted after advancing, but significant force is required to extend the spring and it may prematurely return the cutting member

Engineering Contradiction:

Improvecutting member retractionVSAvoidforce required to extend return spring

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent replaces the traditional return spring mechanism with a flexible band system. The flexible band is wound around a reel and engaged with the cutting member, allowing the cutting member to be retracted without requiring significant force to extend a spring. The flexible band can be easily wound and unwound, providing a more efficient retraction mechanism.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the mechanical parameters of the return mechanism by using a flexible band instead of a rigid spring. This allows for variable tension and force application, enabling the cutting member to be retracted with minimal force while maintaining control over the retraction process.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the end effector is articulated after jaw members are closed, then the end effector can be repositioned, but shear force is applied to the soft tissue

Engineering Contradiction:

Improveend effector repositioningVSAvoidshear force on soft tissue

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a dynamic locking mechanism that allows the end effector to be articulated during the cutting phase but prevents articulation during the stapling phase. The locking mechanism engages automatically when the jaw members are closed, ensuring that the end effector remains in a fixed position to avoid applying shear force to the tissue during the critical stapling operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The locking mechanism provides feedback to the surgeon through tactile sensation. When the jaw members are closed and the locking mechanism engages, the surgeon can feel the locked position, indicating that the end effector is fixed and cannot be articulated. This feedback ensures that the surgeon is aware of the current state of the end effector and can avoid actions that would apply shear force to the tissue.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If a locking mechanism is added to fix the end effector position, then shear forces on tissue are prevented, but device complexity increases

Engineering Contradiction:

Improveshear force on soft tissueVSAvoidlocking mechanism structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the locking mechanism with the existing closure system. The locking mechanism is integrated into the closure trigger assembly, utilizing the same actuation force and mechanical components. This integration ensures that the locking mechanism is activated automatically when the jaw members are closed, providing tissue protection without requiring separate, complex locking components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The locking mechanism serves multiple functions: it prevents articulation during stapling to avoid shear forces, provides tactile feedback to the surgeon, and integrates with the closure system's actuation mechanism. This multi-functionality reduces the need for additional separate mechanisms, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7658311B2Surgical stapling instrument with a geared return mechanism

Publication Date: 2010.02.09 CILAG GMBH INTERNATIONAL

AI summary

A surgical instrument including a firing drive configured to selectively advance a firing member and/or cutting member relative to an end effector and, in addition, a reversing drive configured to selectively retract the firing member and/or cutting member relative to the end effector. The firing drive can include a pawl which can be selectively engaged with the firing member in order to advance the firing member, wherein the pawl can be disengaged from the firing member when the reversing drive is engaged with the firing member. The reversing drive can include a gear train having a first gear operably engaged with the firing member and, in addition, a second gear operably engaged with the first gear, wherein the second gear can be selectively operable with the trigger such that an actuation of the trigger can retract the firing member and/or cutting element via the first and second gears.