Dynamic Injection Flow Control for Subretinal Fluid Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Subretinal injections in the human eye face significant volume losses of injected fluid due to high flow rates, leading to increased injection time and potential leakage, with existing technologies failing to minimize these losses without requiring sealing elements at the distal end of the cannula.
Innovation Solution
A control apparatus for open-loop and/or closed-loop control of the injection flow rate, which increases the flow rate during at least 30% of the injection time or volume, starting with an initial flow rate of less than 5 microliters per second and gradually increasing to minimize volume loss and optimize injection time, using an open-loop or closed-loop control unit to manage the injection flow rate based on tissue separation rates and bleb formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a high injection flow rate is used, then the injection time is reduced, but the volume loss of injected fluid increases due to leakage
Solution Approach 1:
The injection flow rate is dynamically adjusted during the injection process rather than maintained at a constant high rate. The system transitions from an initial low flow rate phase to a subsequent higher flow rate phase, allowing the tissue layers to separate gradually before rapid fluid delivery, thereby minimizing leakage while optimizing injection time
Solution Approach 2:
The injection process begins with a preliminary phase at low flow rate that creates initial separation between the tissue layers and establishes a fluid pathway. This preliminary action prepares the tissue structure to accommodate the subsequent higher flow rate injection, preventing volume loss from occurring
2Productivity
If the injection flow rate is increased, then productivity is improved, but the tissue separation rate cannot keep up causing pressure buildup and leakage
Solution Approach 1:
The system dynamically coordinates the injection flow rate with the tissue separation rate. The injection process is divided into phases where the flow rate adapts to the tissue's ability to separate, ensuring that fluid delivery speed matches tissue accommodation speed, thus maintaining reliability while improving overall productivity
Solution Approach 2:
The injection process incorporates feedback mechanisms that monitor tissue separation progress and adjust the injection flow rate accordingly. This feedback control ensures that the injection rate never exceeds the tissue separation rate, preventing pressure buildup and leakage while maintaining efficient injection delivery
3Loss of substance
If a sealing element is added at the distal end of the cannula, then volume loss is reduced, but the device complexity increases
Solution Approach 1:
The invention extracts and eliminates the sealing element from the cannula structure, achieving volume loss reduction through flow rate control rather than mechanical sealing. This simplifies the device by removing unnecessary components while maintaining effectiveness through the dynamic injection protocol
Solution Approach 2:
The tissue layers themselves perform the sealing function by separating and forming a natural barrier that retains the injected fluid. The biological tissue serves the sealing role that would otherwise require an artificial sealing element, thereby simplifying the device structure while maintaining fluid retention
Data Source
AI summary
A control device for controlling and/or regulating an injection flow rate, when injecting a fluid at an injection site between two tissue layers of the human eye with an injection flow rate that increases with time, is described, which comprises a controlling or regulating unit configured to control the injection flow rate in such a way that the injection flow rate increases during the injection for at least 30% of the injection time or during the injection of at least 30% of the injection volume.