Phacoemulsification Irrigation Pressure Control via Feedback
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Solution Overview
Problem
Phacoemulsification procedures face challenges with varying fluid flow rates causing pressure fluctuations in the eye, leading to unstable intraocular pressure and potential complications like post-occlusion surge due to blockages in the aspirating needle.
Innovation Solution
A computer-implemented surgical system with a pressurized irrigation fluid source, sensors, and a controller that adjusts irrigation pressure based on real-time readings and estimated flow values, using a compensation factor to maintain stable intraocular pressure and manage occlusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional IV pole height control is used to regulate irrigation flow rate, then the system is simple to operate, but intraocular pressure becomes unstable due to varying flow rates causing pressure losses
Solution Approach 1:
The system employs a pressure sensor to continuously monitor intraocular pressure and feeds this information back to a controller. The controller dynamically adjusts the irrigation pump output based on the pressure feedback signal, creating a closed-loop control system that maintains stable intraocular pressure despite variations in flow rate or aspiration demand
Solution Approach 2:
The patent replaces the purely mechanical IV pole height adjustment system with an electronically controlled irrigation pump system. This substitution enables precise electronic control of irrigation flow rate and pressure through the controller and pump mechanism, allowing for dynamic compensation of pressure changes that cannot be achieved through static mechanical positioning alone
2Productivity
If aspiration pump creates high vacuum for effective lens removal, then lens fragments are efficiently aspirated, but post-occlusion surge occurs when the needle becomes blocked and then clears
Solution Approach 1:
The pressure sensor detects changes in aspiration pressure that indicate needle occlusion (abnormal pressure increase) or occlusion clearance (abnormal pressure drop). This feedback signal triggers the controller to automatically adjust irrigation flow rate to compensate for the occlusion event, preventing dangerous pressure surges while maintaining effective lens removal during normal operation
Solution Approach 2:
The system proactively counteracts the harmful effects of occlusion by detecting early pressure changes and preemptively adjusting irrigation flow. When occlusion is detected through pressure feedback, the system increases irrigation pressure before the occlusion fully develops, preventing the dangerous pressure buildup and subsequent surge that would occur with high vacuum alone
3Stability of the object's composition
If irrigation flow rate is increased to maintain intraocular pressure, then pressure stability improves, but pressure losses in the irrigation path increase
Solution Approach 1:
The system dynamically adjusts irrigation flow rate based on real-time intraocular pressure measurements and operational conditions. Rather than maintaining a constant high flow rate that would cause excessive pressure losses, the controller modulates the irrigation pump output to provide exactly the amount of flow needed to maintain stable pressure, minimizing energy waste while ensuring pressure stability
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 system effectively stabilizes intraocular pressure and reduces the risk of post-occlusion surge by dynamically controlling irrigation fluid pressure, ensuring consistent operating conditions during phacoemulsification procedures.
Implementation Method 1
the vibrating tip fragments the lens
Implementation Method 2
The pump action produces aspiration flow through the interior bore of the cutting needle. The aspiration flow results in the creation of vacuum at the aspiration line.
Implementation Method 3
an irrigation pressure sensor located at or along the pressurized irrigation fluid source or irrigation line
Data Source
Figure 1
Figure 2~5
AI summary
A surgical system comprises a pressurized irrigation fluid source; an irrigation line fluidly coupled to the pressurized irrigation fluid source; a hand piece fluidly coupled to the irrigation line; an irrigation pressure senor located at or along the pressurized irrigation fluid source or irrigation line; and a controller for controlling the pressurized irrigation fluid source. The controller controls the pressurized irrigation fluid source based on a reading from the irrigation pressure sensor and an estimated flow value modified by a compensation factor.