Modular Fluidics Cassette for Ocular Surgery
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Solution Overview
Problem
Current eye surgery fluid management systems lack flexibility and precision, as they require different cassettes for displacement-based and vacuum-based aspiration, leading to inconsistent control over fluid volume and pressure, which can cause tissue damage during procedures.
Innovation Solution
A modular console system that accepts interchangeable fluidic cassettes, enabling both displacement-based and vacuum-based aspiration modes, with automatic communication between the console and cassette to establish the appropriate functionality, and the use of a dual mode cassette that includes a separably coupled holding tank for venting and vacuum control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cassette type is used for both displacement-based and vacuum-based aspiration, then device complexity is reduced and ease of manufacture is improved, but control precision over fluid volume and pressure deteriorates
Solution Approach 1:
The system divides the cassette functionality into separate modular components: a common base cassette and optional add-on modules (such as vacuum modules or peristaltic pump modules). This segmentation allows the system to maintain a simple base design while enabling precise fluid control through selective module attachment, resolving the contradiction between device simplicity and control precision.
Solution Approach 2:
The cassette system incorporates dynamic reconfigurability where the functional configuration can be changed during operation. The system can switch between displacement-based aspiration (using peristaltic pumps for precise volumetric control) and vacuum-based aspiration (using vacuum sources for pressure control) by activating different modules or changing cassette configurations, thereby achieving precise fluid control without requiring multiple completely separate cassette types.
2Manufacturing precision
If different cassette types are used for displacement-based and vacuum-based aspiration, then control precision is improved, but device complexity and ease of operation worsen
Solution Approach 1:
The base cassette design incorporates universal interfaces and standardized connection points that can accommodate multiple functional modules. A single base cassette can serve both displacement-based aspiration (by attaching peristaltic pump modules) and vacuum-based aspiration (by attaching vacuum source modules), eliminating the need for surgeons to learn and handle multiple different cassette types while maintaining precise fluid control through module-specific functionality.
3Productivity
If vacuum-based aspiration is used, then productivity is improved for removing large quantities of viscous tissue, but reliability deteriorates due to pressure surges during occlusion
Solution Approach 1:
The vacuum-based aspiration system incorporates feedback mechanisms including pressure sensors that monitor the aspiration pressure in real-time and control systems that adjust vacuum source output based on detected conditions. When occlusion is detected (through pressure surge detection), the system automatically modulates the vacuum source to prevent excessive pressure buildup, thereby maintaining both high productivity during normal operation and reliability during occlusion events.
Solution Approach 2:
The system incorporates compliance elements and pressure relief mechanisms that are pre-configured to cushion against pressure surges before they can cause damage. These may include compliant tubing sections, pressure relief valves, or accumulators that absorb sudden pressure changes during occlusion, protecting the system and maintaining stable operation without sacrificing the high productivity benefits of vacuum-based aspiration.
4Reliability
If peristaltic pumps are used for displacement-based aspiration, then reliability is improved for precise volumetric control, but productivity deteriorates due to slower flow rates
Solution Approach 1:
The system dynamically selects between displacement-based aspiration using peristaltic pumps (for precise volumetric control when needed) and vacuum-based aspiration (for high-speed tissue removal). The control system can switch between modes or combine them during a single procedure, allowing the system to achieve both reliability for volumetric control and productivity for rapid tissue removal by using each method where it excels.
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 provides improved control over fluid management during eye surgery, allowing for precise adjustment of aspiration modes, reducing the risk of tissue damage and enabling efficient handling of different tissues within the eye, while also simplifying cassette production and use.
Implementation Method 1
peristaltic pumps (which use rotating rollers that press against a flexible tubing to induce flow)
Implementation Method 2
vacuum-based aspiration systems using a vacuum source, typically applied to the aspiration flow through an air-liquid interface
Data Source
AI summary
Methods, devices, and systems for laser eye surgery generally make use of a console that interchangeably accepts multiple types of eye treatment cassettes. The cassettes enable one or both of displacement-based or vacuum-based aspiration. The console and the cassette may communicate to establish the functionality of the installed cassette by utilizing a component indigenous to the operation of the cassette. A dual-mode cassette may include a separable holding tank for enabling vacuum-based aspiration. A displacement-based pump may be provided to drain the holding tank while the vacuum system continues to aspirate fluids. A vacuum sensor for controlling the flow of aspirated fluids may have three ports for communicating with a handpiece, a displacement-based pump, a vacuum-based pump, or an irrigation source. The handpiece may be vented during vacuum-based aspiration by opening a vent valve interposed between the handpiece and the vacuum source.