Modulated Phacoemulsification Irrigation and Aspiration
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Solution Overview
Problem
Current phacoemulsification systems face difficulties in efficiently removing tissue during high ultrasonic power delivery due to disruption of fluid flow and formation of cavitation clouds, leading to unpredictable performance and potential clogging, which hampers the surgeon's ability to hold and remove unwanted tissue effectively.
Innovation Solution
The implementation of a modulated irrigation and aspiration system that delivers fluid and power in pulsed bursts, with high amplitude fluid pulses followed by de minimis pulses, and modulated pressure differential pulses to manage cavitation and improve tissue acquisition and removal, while controlling power delivery to the handpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high ultrasonic power is applied continuously to emulsify the cataract, then emulsification efficiency is improved, but cavitation clouds form that disrupt fluid flow and cause unpredictable performance
Solution Approach 1:
The system applies ultrasonic power in periodic bursts rather than continuous operation, with power applied during first time periods and ceased during second time periods. This periodic action allows cavitation clouds to dissipate between bursts, maintaining fluid flow stability while achieving effective emulsification over time.
Solution Approach 2:
The continuous ultrasonic power application is segmented into discrete bursts separated by intervals where power is ceased. This segmentation breaks the continuous cavitation cloud formation into discrete events, allowing fluid flow to stabilize between bursts and improving overall system reliability.
2Productivity
If high vacuum is applied to aspirate emulsified lens quickly, then removal speed is improved, but tissue and fluid clogging in the handpiece occurs
Solution Approach 1:
Vacuum aspiration is applied periodically in coordination with ultrasonic power bursts, rather than continuously. This periodic application allows emulsified material to be cleared from the handpiece lumen at intervals, preventing clogging while maintaining efficient removal speed through coordinated aspiration cycles.
Solution Approach 2:
The system monitors vacuum levels and adjusts aspiration application based on detected conditions, applying vacuum during power bursts when material is being emulsified and coordinating with fluid delivery to clear the lumen, preventing clogging through responsive control.
3Reliability
If fluid is delivered continuously to maintain irrigation, then fluid flow stability is improved, but cavitation clouds are not effectively managed
Solution Approach 1:
Fluid delivery is synchronized with ultrasonic power bursts, delivering fluid during power application and reducing or ceasing delivery during power-off intervals. This periodic fluid management helps clear cavitation clouds from the handpiece lumen while maintaining adequate irrigation during active emulsification.
Solution Approach 2:
The system maintains continuous coordination between fluid delivery and power application, ensuring fluid is available during emulsification bursts while using the periodic nature of the bursts to manage cavitation. The useful action of irrigation continues through coordinated timing rather than simple continuous flow.
4Productivity
If power bursts are applied with longer duration to reduce treatment time, then productivity is improved, but cavitation-related disruptions increase
Solution Approach 1:
The system uses regularly spaced power bursts with consistent timing intervals, allowing the surgical procedure to progress efficiently while maintaining predictable cavitation patterns. The periodic nature ensures cavitation clouds dissipate between bursts, maintaining performance predictability even at higher treatment speeds.
Solution Approach 2:
The system dynamically adjusts the timing and duration of power bursts based on surgical conditions, optimizing treatment speed while preventing excessive cavitation buildup. The dynamic control allows adaptation to maintain reliability as the procedure progresses and tissue conditions change.
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 enhances tissue removal efficiency by minimizing cavitation-related disruptions, allowing for effective acquisition and removal of tissue even in high power environments, reducing clogging risks, and maintaining stable fluid flow, thereby improving surgical outcomes.
Implementation Method 1
The hollow needle of the handpiece may typically be driven or excited along its longitudinal axis by the piezoelectric effect in crystals created by an AC voltage applied thereto.
Implementation Method 2
Certain previous systems address the requirements of power control for a phacoemulsification handpiece based on the phase angle between voltage applied to a handpiece piezoelectric transducer and the current drawn by the piezoelectric transducer and/or the amplitude of power pulses provided to the handpiece.
Implementation Method 3
The handpiece includes a needle which is ultrasonically driven once placed within an incision to emulsify the eye lens, or break the cataract into small pieces.
Implementation Method 4
Currently available phacoemulsification systems include a variable speed peristaltic pump, a vacuum sensor, an adjustable source of ultrasonic power, and a programmable microprocessor with operator-selected presets for controlling aspiration rate, vacuum and ultrasonic power levels.
Data Source
AI summary
A method and apparatus for performing modulated fluid delivery and aspiration during a surgical procedure such as phacoemulsification is provided. The method and apparatus include delivering fluid and/or aspirating fluid in a modulated or pulsed manner during a surgical procedure, including applying fluid and/or aspirating fluid in connection with ultrasonic energy at a level and for a time period sufficient to induce transient cavitation. Fluid may be applied and/or aspirated at a timing sequence and duty cycle similar to or different from application of ultrasonic energy delivery.