Powered Stapling Apparatus Spring Constant Adjustment

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Solution Overview

Problem

Conventional powered stapling apparatuses lack the ability to effectively test and adjust the operational efficacy of their components, leading to inconsistent compressive force during tissue stapling due to wear and degradation from sterilization and prolonged use.

Innovation Solution

A powered stapling apparatus with a spring-loaded cartridge assembly and a microcontroller that tests the spring constant of a resilient member, adjusting the motor current based on the tested value to maintain a consistent compressive force, using a data look-up table to compare the tested spring constant with known values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the handle assembly is reused and sterilized multiple times, then cost-effectiveness is improved, but the operational efficacy of components (gears, links, resilient member) deteriorates due to wear and degradation

Engineering Contradiction:

Improvecost-effectivenessVSAvoidoperational efficacy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The microcontroller measures current draw during operation and compares it against expected values to detect changes in resilient member properties. This feedback mechanism allows the system to monitor degradation and adjust operation accordingly, maintaining reliability while enabling handle reuse for cost-effectiveness.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes operational parameters (motor current, compression force) based on detected resilient member degradation. By adjusting these parameters in real-time, the system compensates for wear and maintains consistent stapling performance despite repeated sterilization cycles.

Inventive Principle:

Principle #35Parameter changes

2Force

If the resilient member is compressed to provide sufficient compressive force for stapling, then stapling effectiveness is improved, but the risk of excessive current draw and motor damage increases

Engineering Contradiction:

Improvecompressive forceVSAvoidexcessive current draw

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The microcontroller continuously monitors motor current during compression and uses this feedback to prevent excessive current draw. By detecting current trends and comparing against thresholds, the system can interrupt or limit compression before damaging levels are reached, protecting the motor while maintaining adequate stapling force.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts compression force based on real-time current measurements. Rather than applying fixed maximum force, the motor control adapts the compression profile to match actual resilient member properties and tissue conditions, optimizing the balance between stapling effectiveness and motor protection.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If conventional microcontrollers are used without testing capabilities, then device complexity is reduced, but the ability to detect and respond to component degradation is lost

Engineering Contradiction:

Improvemicrocontroller configurationVSAvoidcomponent efficacy testing

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The microcontroller performs self-testing by measuring its own current draw during operation and comparing against expected values. This self-service approach enables degradation detection without adding external testing equipment, maintaining relatively simple device architecture while gaining diagnostic capability.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system replaces complex mechanical testing mechanisms with electrical measurements. By using current draw as a proxy for resilient member condition, the system achieves degradation detection through simple electrical sensing rather than mechanical testing apparatus.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 consistent and specific compressive force for tissue stapling, extending the operational lifespan of the stapler by monitoring and controlling the current input to the motor, thereby maintaining optimal stapling performance despite component wear.

Implementation Method 1

A resilient member may be operably positioned within the cartridge assembly and configured to bias the staple guide distally; this provides a predetermined compressive force against tissue when the cartridge assembly and anvil are approximated toward one another

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS10463373B2Powered stapling apparatus

Publication Date: 2019.11.05 COVIDIEN LP

AI summary

A stapler is provided. The stapler includes a handle assembly and a shaft extending distally from the handle assembly. A tool assembly is configured to selectively couple to the shaft and includes a cartridge assembly and an anvil assembly. The cartridge assembly includes a staple guide defining a tissue contacting surface. A resilient member operably positioned within the cartridge assembly is configured to bias the staple guide distally to provide a predetermined compressive force against tissue when the cartridge assembly and anvil are approximated toward one another.