Vitrectomy Apparatus Multisensor Pressure Feedback Control
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Solution Overview
Problem
Current pneumatic vitrectomy systems face challenges in maintaining consistent cutting pressures during surgical procedures, often requiring large fluid reservoirs and being prone to pressure inconsistencies due to environmental changes and minor leaks, which can affect the quality of vitreous cutting.
Innovation Solution
A vitrectomy apparatus with a pressure source, cut valve, and multiple sensors connected to a controller that adjusts the pressure source duty cycle based on real-time pressure readings to maintain consistent cutting pressures, reducing the need for a large fluid reservoir and accommodating changes in the surgical environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large fluid reservoir or accumulator is used to maintain consistent pressure, then pressure consistency is improved, but device size and complexity increase
Solution Approach 1:
The system employs multiple pressure sensors positioned at different points between the pressure source and cut valve, with a controller that continuously monitors pressure readings and dynamically adjusts the pressure source duty cycle to maintain consistent cutting pressure. This closed-loop feedback control eliminates the need for large fluid reservoirs while ensuring reliable pressure consistency.
Solution Approach 2:
The system transitions from a static pressure maintenance approach (relying on large accumulators) to a dynamic control approach where the pressure source duty cycle is continuously adjusted based on real-time sensor feedback, allowing consistent pressure to be maintained with a compact system design.
2Adaptability or versatility
If calibration settings are used to account for environmental changes, then adaptability to fixed environmental factors is improved, but ability to handle rapidly changing environmental factors deteriorates
Solution Approach 1:
The real-time pressure feedback system continuously monitors actual cutting pressure and dynamically adjusts the pressure source duty cycle to compensate for rapidly changing environmental factors such as temperature variations and electro-mechanical pump drift, maintaining reliable pressure consistency where fixed calibration settings would fail.
3Speed
If the frequency of opening and closing the pneumatic valve is varied to achieve desired cutting speed, then cutting speed control is improved, but pressure consistency deteriorates
Solution Approach 1:
The system decouples speed control from pressure control by using feedback to dynamically adjust the pressure source duty cycle, allowing the valve frequency to be varied for speed control while the feedback mechanism simultaneously compensates for any pressure variations, maintaining both speed flexibility and pressure consistency.
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 solution enables precise and consistent pneumatic cutting pressures, improving the efficiency and accuracy of vitreous material removal during vitrectomy procedures by dynamically adjusting the pressure source duty cycle in response to sensed pressure variations.
Implementation Method 1
a pressure source, a cut valve connected to the pressure source, the cut valve configured to be turned on and off to provide pressure to selectively extend and retract a vitrectomy cutting device
Implementation Method 2
a plurality of sensors provided at a plurality of points between the pressure source and a vitrectomy handpiece
Implementation Method 3
a controller configured to selectively provide commands to change pressure source duty cycle according to a plurality of linear functions when one sensor of the plurality of sensors measures a pressure outside a predetermined pressure range
Data Source
Figure 1A~1B
Figure 2A~2D
Figure 3
AI summary
A vitrectomy apparatus is provided, including a pressure source, a cut valve connected to the pressure source, the cut valve configured to be turned on and off to provide pressure to selectively extend and retract a vitrectomy cutting device, a plurality of sensors provided at a plurality of points between the pressure source and the vitrectomy handpiece, and a controller configured to employ a function correlating a desired cut rate with a pressure source duty cycle and employ a different function when one sensor of the plurality of sensors senses a pressure outside a predetermined pressure range.