Surgical Stapler Spline Crash Correction via Motor Oscillation

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Solution Overview

Problem

Circular stapling devices face issues with spline crash, which can damage components and prevent proper alignment of staple forming pockets with receiving pockets, leading to malformation or failure in tissue fastening.

Innovation Solution

A surgical stapler with a motor-driven anvil retainer that oscillates between extension and retraction patterns to prevent spline crash by realigning the anvil and shell assemblies, using a processing unit to control the motor and sensors to detect and correct clamping force thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the anvil assembly and shell assembly are approximated to align staple forming pockets with receiving pockets, then proper alignment and staple formation are achieved, but spline crash may occur causing component damage and alignment failure

Engineering Contradiction:
Improvealignment precisionVSAvoidcomponent reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The motor is configured to oscillate the anvil retainer between extension and retraction positions, creating controlled mechanical vibration that prevents the splines from crashing into each other. This vibration allows the splines to pass by one another smoothly during approximation, eliminating the crash condition while maintaining proper alignment.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The system employs periodic oscillation of the anvil retainer between extension and retraction positions during the approximation process. This periodic action continues until the splines have safely passed one another, ensuring reliable alignment without component damage.

Inventive Principle:
Principle #19Periodic action

2Ease of operation

If the splines are designed to engage smoothly, then alignment is facilitated, but simultaneous engagement of tapered ends causes spline crash and binding

Engineering Contradiction:
Improvealignment easeVSAvoidspline crash
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The motor-generated oscillation introduces controlled vibration that prevents simultaneous engagement of the tapered spline ends. This vibration ensures that splines engage sequentially rather than simultaneously, eliminating the harmful crash effect while maintaining ease of alignment.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The system converts the potentially harmful simultaneous engagement force into a beneficial oscillatory motion. By introducing controlled vibration through motor oscillation, the harmful crash condition is transformed into a safe sequential engagement process that facilitates alignment.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If the anvil retainer is extended fully to ensure alignment, then proper positioning is achieved, but the risk of spline crash increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidspline crash risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The motor oscillates the anvil retainer between extension and retraction positions, creating vibration that prevents spline crash even during full extension. This allows the system to achieve maximum positioning precision without the harmful effects of spline engagement crash.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The anvil retainer is made dynamic through motor-controlled oscillation between extension and retraction positions. This dynamic behavior allows the system to achieve precise positioning while the oscillation prevents the static harmful condition of spline crash.

Inventive Principle:
Principle #15Dynamics

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 effectively prevents spline crash, ensuring proper alignment and reducing the risk of damage, thereby ensuring reliable staple formation and tissue clamping during surgical procedures.

Implementation Method 1

The motor is configured to oscillate the anvil retainer between extension and retraction in a first oscillation pattern to obviate a spline crash between the anvil spline and the shell spline

Methodology Applied
Scientific EffectOscillation: Harmonic Oscillator

Data Source

PatentEP3714810B1Spline crash correction with motor oscillation
Publication Date: 2024.12.25 COVIDIEN LP
  • EP3714810B1 patent drawingFigure 1
  • EP3714810B1 patent drawingFigure 2
  • EP3714810B1 patent drawingFigure 3

AI summary

A method for obviating spline crash in a surgical stapler that utilizes a motor of the surgical stapler includes oscillating an anvil retainer of the surgical stapler in a first oscillation pattern, oscillating the anvil retainer in a second oscillation pattern that is different from the first oscillation pattern after the first oscillation pattern, and retracting the anvil retainer until an anvil of the surgical stapler is in a clamped position relative to a shell assembly after the second oscillation pattern. Oscillating the anvil retainer in the first oscillation pattern includes oscillating the anvil retainer in a longitudinal direction between extension and retraction with the motor such that the anvil moves towards and away from the shell assembly. Oscillating the anvil retainer in the second oscillation pattern includes moving the anvil towards and away from the shell assembly.