Phacoemulsification Cannula Venturi Lumen Suction
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Solution Overview
Problem
Existing phacoemulsification cannulas face challenges in maintaining effective contact with cataract tissue due to the longitudinal motion of the cannula, which pushes the cataract away, requiring increased aspiration levels that can lead to fluid surges and potential eye damage.
Innovation Solution
A phacoemulsification cannula design featuring a venturi lumen with a double hour-glass shape near the distal end, creating a significant increase in suction power by smoothly transitioning from a large to a small and then back to a larger diameter, enhancing fluid velocity and suction without increasing aspiration levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If aspiration levels are increased to provide greater purchase of the cataract, then the cannula can hold the cataract more effectively, but fluid surges occur causing collapse of the eye and damage to delicate tissues
Solution Approach 1:
The patent changes the geometric parameters of the lumen by introducing a venturi section with a reduced diameter region. This modifies the flow characteristics and pressure distribution within the lumen, enabling effective cataract purchase at lower aspiration levels. The venturi geometry creates a pressure gradient that enhances suction force on the cataract while preventing harmful fluid surges during occlusion clearance.
2Power
If the cannula moves longitudinally during ultrasonic vibration, then ultrasonic energy is delivered to break-up cataract tissue, but the cannula pushes the cataract away reducing contact effectiveness
Solution Approach 1:
The patent modifies the lumen geometry with a venturi section that creates favorable pressure gradients. This pressure distribution helps maintain cataract contact with the cannula tip during ultrasonic vibration, preventing the cataract from being pushed away while still allowing effective ultrasonic energy delivery for tissue break-up.
3Ease of manufacture
If a straight or tapered bore is used in the cannula, then manufacturing is simple, but suction power at the distal end is insufficient
Solution Approach 1:
The patent introduces a venturi section with a reduced diameter region into the lumen geometry. While this adds some manufacturing complexity compared to straight or tapered bores, it significantly enhances suction power at the distal end. The venturi geometry creates velocity pressure that concentrates suction force at the tip, providing effective cataract purchase without requiring excessive aspiration levels.
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 design achieves at least four times greater suction power compared to prior art cannulas, allowing safer and more efficient manipulation and aspiration of cataract tissue at standard aspiration levels, reducing the risk of fluid surges and eye damage.
Implementation Method 1
A phacoemulsification cannula design featuring a venturi lumen with a double hour-glass shape near the distal end, creating a significant increase in suction power by smoothly transitioning from a large to a small and then back to a larger diameter, enhancing fluid velocity and suction
Data Source
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AI summary
A phacoemulsification cannula (10) includes a hub (12) for engagement with an ophthalmic surgical instrument. An elongated needle (14) having a proximal end (16) is attached to the hub (12). The cannula (10) has an aspiration lumen (20) spanning a majority of a length of a needle (14) from the proximal end towards a distal end (18). A venturi lumen (22) is formed in the needle adjacent the distal end. The venturi lumen (22) is in communication with the aspiration lumen (20) so that fluid and tissue may be aspirated through the venturi lumen (22) and the aspiration lumen (20).