Dual Frequency Phacoemulsification Circuit for Cataract Surgery
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Solution Overview
Problem
Current phacoemulsification devices using ultrasonic needles face challenges in efficiently fragmenting and emulsifying cataractous lenses due to inadequate control over cavitation and heat generation, leading to reduced followability and increased risk of occlusions during eye surgery.
Innovation Solution
A dual frequency phacoemulsification device with a hollow needle driven by a piezoelectric crystal transducer, capable of switching between low-frequency (below 60 kHz) and high-frequency (equal to or above 60 kHz) vibrations, which produces a single node of minimum amplitude, reducing cavitation and heat while enhancing tissue penetration and followability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultrasonic needle is used at conventional single frequency for lens fragmentation, then lens emulsification is achieved, but excessive cavitation and heat generation occur leading to reduced followability and increased occlusion risk
Solution Approach 1:
The system dynamically switches between low-frequency (below 60 kHz) and high-frequency (60 kHz or above) vibration modes of the ultrasonic needle based on real-time surgical conditions. This dynamic frequency adjustment allows optimization of lens emulsification efficiency while controlling harmful cavitation and heat effects, directly resolving the technical contradiction between productivity and harmful factors.
Solution Approach 2:
The invention changes the operating frequency parameter of the ultrasonic needle from a fixed single frequency to a variable dual-frequency system. By switching between low-frequency mode (for reduced cavitation) and high-frequency mode (for enhanced emulsification), the system optimizes the balance between lens fragmentation efficiency and harmful side effects, resolving the contradiction between emulsification effectiveness and cavitation control.
2Reliability
If high-frequency vibration (≥60 kHz) is applied to produce node of minimum amplitude, then followability and tissue penetration are enhanced, but device complexity increases due to dual frequency switching circuitry
Solution Approach 1:
The system employs periodic switching between high-frequency and low-frequency vibration modes rather than continuous operation at a single frequency. The high-frequency mode (≥60 kHz) is activated during phases requiring enhanced followability and tissue penetration, while the low-frequency mode is used during lens emulsification phases. This periodic action allows the system to achieve reliable performance when needed while managing overall device complexity through controlled frequency transitions.
3Object-affected harmful factors
If low-frequency vibration (<60 kHz) is used to reduce cavitation, then heat generation is reduced, but lens fragmentation efficiency decreases
Solution Approach 1:
The ultrasonic vibration process is segmented into distinct frequency phases: low-frequency vibration (<60 kHz) is used during lens emulsification to reduce cavitation and heat generation, while high-frequency vibration (≥60 kHz) is applied during followability-critical phases. This segmentation of the surgical process into frequency-specific stages allows the system to minimize harmful effects during emulsification while maintaining efficiency through subsequent high-frequency tissue penetration and followability enhancement.
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 dual frequency approach effectively fragments and emulsifies cataractous lenses with reduced cavitation and heat generation, improving followability and reducing occlusions, thereby enhancing the efficiency and safety of the phacoemulsification procedure.
Implementation Method 1
a hollow needle extending from a handpiece that includes a piezoelectric crystal transducer connected to a dual frequency producing circuit
Implementation Method 2
The two frequencies produce different surgical effects when used to emulsify a cataractous lens
Implementation Method 3
The high-frequency oscillator is configured to drive the piezoelectric crystal transducer to periodically vibrate the hollow needle at a high frequency of more than or equal to 60 kHz while producing a single node of minimum amplitude along the hollow needle
Data Source
AI summary
Disclosed is a surgical instrument directed to phacoemulsification for cataract eye surgery. The instrument generally includes a dual frequency voltage producing circuit comprising a low-frequency voltage pathway with a low-frequency LC Network and a high-frequency voltage pathway with a high-frequency LC network. A phacoemulsification needle extends from a handpiece able to be driven by a piezoelectric transducer. The piezoelectric transducer is electrically connected to the dual frequency voltage producing circuit. The high-frequency voltage pathway is electrically tuned with the physical high natural frequency of the handpiece and the low-frequency voltage pathway is electrically tuned with the physical low natural frequency of the handpiece for efficient transfer of energy.