Phacoemulsification Hand Piece Vacuum Control via Pulsed Motion

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Solution Overview

Problem

Conventional phacoemulsification systems face challenges in effectively controlling the motion of the cutting tip during cataract surgery, particularly in managing occlusions that can lead to clogging and fluctuations in vacuum pressure, which may cause undesirable effects such as anterior chamber collapse.

Innovation Solution

The system employs a series of power pulses to the hand piece, adjusting the duration and type of motion (torsional, simultaneous torsional and longitudinal, and longitudinal) based on vacuum pressure measurements to optimize cutting efficiency and clear occlusions, ensuring effective lens removal while maintaining stable vacuum levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If torsional motion is used to prevent repulsion of lens material, then lens removal efficiency is improved, but cutting tip occlusion increases

Engineering Contradiction:
Improvelens removal efficiencyVSAvoidcutting tip occlusion
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system applies periodic power pulses to the hand piece, alternating between torsional motion phases (for cutting efficiency) and longitudinal motion phases (for clearing occlusions). This periodic switching prevents sustained occlusion while maintaining high lens removal efficiency during torsional phases.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the type of motion (torsional vs. longitudinal) based on real-time vacuum pressure feedback. When occlusion is detected via vacuum fluctuation, the system transitions from torsional to longitudinal motion to clear the blockage, then returns to torsional motion for continued efficient cutting.

Inventive Principle:
Principle #15Dynamics

2Object-generated harmful factors

If longitudinal motion is used to clear occluded tip, then cutting tip occlusion is reduced, but lens removal efficiency decreases

Engineering Contradiction:
Improvecutting tip occlusionVSAvoidlens removal efficiency
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The system uses periodic power pulses that alternate between torsional motion (high efficiency cutting) and longitudinal motion (occlusion clearing). The longitudinal motion is applied only periodically when needed to clear occlusions, minimizing its impact on overall lens removal efficiency.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically switches between motion types based on vacuum pressure feedback. Longitudinal motion is activated only when occlusion is detected, allowing the system to maintain high torsional motion usage for efficient lens removal while clearing occlusions only when necessary.

Inventive Principle:
Principle #15Dynamics

3Productivity

If vacuum pressure is increased to improve aspiration, then lens material removal is enhanced, but anterior chamber collapse risk increases

Engineering Contradiction:
Improveaspiration efficiencyVSAvoidanterior chamber collapse
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors vacuum pressure and uses this feedback to control power delivery to the hand piece. When vacuum pressure approaches levels that could cause anterior chamber collapse, the system automatically reduces power or switches motion types to prevent harmful effects while maintaining effective aspiration during safe vacuum ranges.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts power levels and motion types based on real-time vacuum pressure conditions. During phases when vacuum is stable and safe, higher power levels are used for effective aspiration. When vacuum approaches critical levels, the system reduces power or switches to longitudinal motion to prevent anterior chamber collapse.

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

This approach allows for precise control of the cutting tip motion, enhancing lens removal efficiency and preventing occlusions, thereby reducing the risk of anterior chamber collapse and improving surgical outcomes.

Implementation Method 1

The crystals supply the required ultrasonic vibration needed to drive both the horn and the attached cutting needle during phacoemulsification

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The tip of the cutting needle and the end of the irrigation sleeve are inserted into the anterior capsule of the eye through a small incision in the outer tissue of the eye. The surgeon brings the tip of the cutting needle into contact with the lens of the eye, so that the vibrating tip fragments the lens.

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP2709575B1Vacuum level control of power for phacoemulsification hand piece
Publication Date: 2015.05.13 ALCON RESEARCH LTD
  • EP2709575B1 patent drawingFigure 1
  • EP2709575B1 patent drawingFigure 2A~2D
  • EP2709575B1 patent drawingFigure 3A~3B

AI summary

The present invention comprises a method of operating an ophthalmic surgical hand piece, providing a series of power pulses to the hand piece, each of the series of power pulses having a first portion that produces torsional movement of a cutting tip and a second portion that produces longitudinal movement of the cutting tip; measuring vacuum pressure; altering the duration of the first portion as vacuum pressure increases; and altering the duration of the second portion as vacuum pressure increases.