Surgical Fastener Linear Position Sensor

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Solution Overview

Problem

Existing surgical fastener apparatuses face challenges in accurately determining the location of the pusher during the firing stroke due to variations in manufacturing tolerances, fastener sizes, and tissue thickness, which can impact the effectiveness of tissue anastomosis.

Innovation Solution

A surgical fastener apparatus equipped with a linear position sensor and a controller that uses calibration data to determine the position of the pusher through the firing stroke, incorporating a spring member and strain gauge to send output signals, allowing for precise control of the firing stroke and accommodation of variations in tool types and fastener sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a linear position sensor with strain gauge is added to the fastener apparatus, then measurement precision of pusher position is improved, but device complexity increases

Engineering Contradiction:
Improvepusher position measurementVSAvoidsensor and controller integration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical position measurement systems with a linear position sensor that uses electromagnetic or optical fields to detect pusher position. The strain gauge provides electrical signals that correspond to pusher position, eliminating the need for complex mechanical encoders or multiple physical sensors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The strain gauge acts as an intermediary element that converts mechanical displacement of the pusher into electrical signals. This intermediary converts physical position into a measurable electrical parameter, simplifying the overall measurement system while maintaining high precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If calibration data storage and comparison functions are added to the controller, then reliability of anastomosis procedure is improved, but device complexity increases

Engineering Contradiction:
Improveanastomosis procedure effectivenessVSAvoidcontroller programming and memory
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller stores calibration data in advance that corresponds to various pusher positions and fastener types. This preliminary data storage allows the system to quickly compare actual sensor readings against pre-established reference values during the procedure, ensuring reliable anastomosis without real-time complex calculations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the linear position sensor output and comparing it against stored calibration data. This feedback mechanism ensures the pusher reaches the correct position for effective fastener deployment, improving procedural reliability through automated verification.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the apparatus accommodates variations in manufacturing tolerances and fastener sizes, then adaptability is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveaccommodation of variationsVSAvoidcomponent dimensional consistency
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts to variations in fastener size and manufacturing tolerances by using the linear position sensor to detect actual pusher position and comparing it against stored calibration data for different fastener types. This dynamic adaptation allows the apparatus to accommodate variations without requiring extremely tight manufacturing tolerances on all components.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller can change operational parameters based on the detected fastener type and size, adjusting the expected pusher travel distance and position criteria. This parameter adjustment allows the system to adapt to different fastener specifications while maintaining consistent performance across variations.

Inventive Principle:
Principle #35Parameter changes

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 solution significantly improves the success rate of the firing stroke by providing accurate location information of the pusher relative to the fastener cartridge, ensuring effective anastomosis of tissue sections, even with variations in manufacturing tolerances and fastener sizes.

Implementation Method 1

a strain gauge mounted to the spring member. The strain gauge is adapted to send the at least one output signal

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Data Source

PatentEP3178415B1Surgical fastener apparatus with linear position sensor
Publication Date: 2019.08.28 COVIDIEN LP
  • EP3178415B1 patent drawingFigure 1
  • EP3178415B1 patent drawingFigure 2
  • EP3178415B1 patent drawingFigure 3~5

AI summary

A fastener apparatus includes a handle, an elongate body connected to the handle, a fastener cartridge disposed adjacent the distal end of the elongate body and having at least one fastener, a pusher at least partially disposed within the elongate body, and adapted for longitudinal movement through a firing stroke to eject the at least one fastener from the fastener cartridge, a linear position sensor mounted within the elongate body and dimensioned and positioned to engage the pusher during movement through the firing stroke and being adapted to send at least one output signal representative of strain imparted thereupon by the pusher during the firing stroke, and a controller configured and adapted to determine a position of the pusher within the firing stroke based upon the at least one output signal.