Asymmetric Phacoemulsification Needle for Efficient Lens Fragmentation
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Solution Overview
Problem
Current phacoemulsification techniques face inefficiencies due to the need for large incisions and potential damage to delicate eye tissues from heat and tissue collapse, particularly when using torsional handpieces, which are more expensive and less commonly used due to their complexity.
Innovation Solution
A phacoemulsification needle with an off-axis configuration, featuring a straight or angled tip and aspiration passageway offset from the needle body, is designed for use with both longitudinal and torsional handpieces, creating a hybrid motion that enhances efficiency and reduces heat production by minimizing energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If torsional handpieces are used for phacoemulsification, then cutting efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The needle is designed with an asymmetric cross-sectional shape (e.g., oval, rectangular, or triangular) rather than a symmetric circular shape. This asymmetric geometry creates differential cutting action during longitudinal vibration, with one side of the needle engaging tissue more aggressively than the other, thereby improving cutting efficiency without requiring complex torsional mechanisms
Solution Approach 2:
Instead of using torsional motion (rotational vibration) to improve cutting efficiency, the invention inverts the approach by using longitudinal vibration with an asymmetric needle shape to achieve the same or better cutting performance. This simplifies the handpiece design while maintaining or enhancing productivity
2Device complexity
If longitudinal handpieces are used for phacoemulsification, then device complexity is reduced, but cutting efficiency decreases
Solution Approach 1:
The asymmetric needle cross-section creates unequal engagement between the needle sides and tissue during longitudinal vibration. One side of the asymmetric needle acts as a cutting edge while the other side provides support, enabling efficient tissue fragmentation with simple longitudinal motion
Solution Approach 2:
Different portions of the asymmetric needle have different functional qualities - one side is designed for aggressive cutting while the other provides stability and support. This local differentiation of function within the single needle enables efficient phacoemulsification using simple longitudinal vibration
3Ease of operation
If larger incisions are made in the capsular bag, then lens removal is facilitated, but tissue damage and liquid leakage increase
Solution Approach 1:
The diseased lens is fragmented into small particles through ultrasonic vibration of the asymmetric needle, allowing removal through a small incision. The segmentation of the lens into aspiratable particles enables minimal incision surgery while avoiding the tissue damage associated with large incisions
Solution Approach 2:
The invention replaces mechanical leverage (which would require large incisions for manual lens removal) with ultrasonic vibration and asymmetric geometry to achieve lens fragmentation. This substitution enables effective lens removal through small incisions, reducing tissue trauma and improving surgical outcomes
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 design allows for more efficient phacoemulsification with reduced heat production and tissue damage, achieving better outcomes with lower energy dissipation and faster operation times, even when used with less expensive longitudinal handpieces, while maintaining effectiveness across various operating frequencies.
Implementation Method 1
Electrical energy is applied to a piezoelectric crystal to vibrate the needle at ultrasonic frequencies
Implementation Method 2
vibrate the needle at ultrasonic frequencies in order to fragment the diseased lens into small enough particles
Implementation Method 3
aspirated from the eye through the hollow needle
Data Source
AI summary
A phacoemulsification needle having a hollow passageway terminates in a straight needle tip having a rectangular cross-sectional shape larger than the cross-sectional shape of the needle passageway. The tip is formed off-axis from the passageway, allowing the needle tip to move eccentrically when the needle is subjected to torsional or longitudinal vibratory motion. The inner and outer surfaces of the needle tip are roughened, as by sandblasting, to enhance the cutting effect of the tip when used with a non-longitudinal handpiece. The lip of each needle tip is polished to a high degree of smoothness and the edges of the tip are rounded to lessen the incidence of snags or cuts.