Aperiodic Pulse Control for Phacoemulsification
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Solution Overview
Problem
Current phacoemulsification techniques face challenges in efficiently breaking down and aspirating lens particles with varying hardness using high energy input, which can lead to corneal burning and increased operation time due to temperature issues and kinetic energy conversion of vibration energy.
Innovation Solution
An ophthalmic surgical pulse control device generates pulses with an aperiodic sequence of durations and pauses, optimizing energy input to effectively break down both small and large lens particles with minimal energy, preventing local heating and ensuring efficient aspiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high energy input with large amplitude needle oscillation is used to generate lens particles quickly, then particle generation speed is improved, but temperature increases causing corneal burning and pushing particles away from needle tip
Solution Approach 1:
The patent applies periodic pulsed ultrasonic action instead of continuous high-energy oscillation. The needle delivers short bursts of ultrasonic energy followed by pause periods, allowing heat dissipation during intervals. This periodic on-off cycling maintains particle generation effectiveness while preventing excessive temperature buildup that would cause corneal burning and particle ejection.
Solution Approach 2:
The patent dynamically adjusts the amplitude and duration of needle oscillation during the procedure. Rather than maintaining constant high amplitude, the system varies the oscillation parameters in real-time based on tissue response and temperature considerations, optimizing particle generation while minimizing thermal damage to surrounding corneal tissue.
2Temperature
If low ultrasonic energy is used to avoid temperature increase, then corneal burning is prevented, but operation time significantly increases and large hard particles cannot be crushed
Solution Approach 1:
The pulsed ultrasonic delivery system allows accumulation of therapeutic effect over time while limiting peak temperature. By delivering multiple short energy bursts with cooling intervals, the system achieves effective lens particle generation and large particle fragmentation without sustained high temperatures, thus preventing corneal burning while maintaining reasonable operation time.
Solution Approach 2:
The patent changes the temporal parameters of ultrasonic energy delivery by introducing pulse duration, pulse interval, and duty cycle variations. This parameter modulation enables the system to deliver sufficient total energy for crushing large hard particles while distributing it over time to prevent excessive temperature rise, resolving the contradiction between effective particle generation and thermal safety.
3Ease of operation
If repetitive pulse patterns are used for consistent energy delivery, then control simplicity is improved, but standing waves form causing local heating and reducing effectiveness on particles with varying hardness
Solution Approach 1:
The patent introduces asymmetry and variability into the pulse pattern by varying pulse duration, interval, and amplitude between successive pulses rather than using identical repetitive patterns. This irregular pulsing prevents the formation of standing waves that would cause localized heating, while still maintaining straightforward device operation through automated control algorithms that manage the variable parameters.
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 device enables efficient emulsification and aspiration of lens particles with reduced energy input and shorter operation times, minimizing corneal heating and accommodating lenses of different hardness levels.
Implementation Method 1
a thin needle is inserted into the diseased lens and vibrated with ultrasound. The vibrating needle emulsifies the lens in its immediate vicinity
Implementation Method 2
generate pulses with a pulse duration during an on-time of the pulse generator with a pulse duration in which the needle of a phacoemulsification handpiece oscillates essentially in resonance
Implementation Method 3
the resulting lens fragments can be aspirated through a line by a pump
Data Source
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AI summary
The device relates to an ophthalmic surgical pulse control device comprising a pulse generator which is set up to generate, for a switch-on duration of the pulse generator, pulses having a pulse duration in which the needle of a phacoemulsification tool holder oscillates substantially in resonance, and which is set up to generate during a switch-on duration of the pulse generator, pulse pauses having a pulse duration in which the needle oscillates only minimally or not at all, wherein a pulse followed by a pulse pause forms a pulse packet having a pulse packet duration, wherein the pulse generator is set up to generate immediately successive pulse packets, wherein the sequence of the amounts of the pulse duration and the pulse pause duration of successive pulse packets has an aperiodic sequence throughout the entire switch-on duration.