Grooved Needle Tip for Ultrasonic Phacoemulsification
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Solution Overview
Problem
Current ultrasonic surgical needle tips, particularly those designed for phacoemulsification, face inefficiencies in cutting and emulsification due to poor ergonomics and clogging issues when using torsional and transverse ultrasonic handpieces, especially with harder or denser cataract material, and lack compatibility with rotary tip motions.
Innovation Solution
A needle tip configuration featuring grooves milled into the internal surface and throat of the tip, with asymmetric and varying arrangements around the circumference, creating a D-shaped mouth and stepped edges to enhance cutting efficiency, fluidics, and prevent clogging, while accommodating torsional and transverse ultrasonic vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard round tip on a straight needle is used, then the design is simple and compatible with longitudinal ultrasound, but it cannot work with torsional ultrasound handpieces as the rotary tip motion simply cores out the material rather than breaking and emulsifying it
Solution Approach 1:
The needle tip is designed with an asymmetric configuration featuring a flattened posterior surface and a curved anterior surface, creating a D-shaped tip mouth. This asymmetric geometry enables the tip to effectively engage with torsional and transverse ultrasonic handpieces, transforming rotary needle motion into a sweeping or scything tip motion that efficiently breaks and emulsifies lens material rather than simply coring it out
Solution Approach 2:
The tip configuration is segmented into distinct functional zones: a flattened posterior surface for structural support and alignment, a curved anterior surface for optimal tissue engagement, and a D-shaped tip mouth with specific dimensional ratios (minor axis 0.4-0.6mm, major axis 0.6-0.8mm). This segmentation allows each portion to contribute specifically to the overall emulsification efficiency while maintaining compatibility with rotary ultrasonic motion
2Productivity
If a bent needle is used to transform rotary needle motion into sweeping tip motion, then torsional ultrasound effectiveness is improved, but the needle has poor ergonomics and is difficult to use during phacoemulsification surgery
Solution Approach 1:
The asymmetric D-shaped tip configuration enables effective torsional ultrasound operation without requiring a bent needle design. The flattened posterior surface and curved anterior surface work together to transform rotary motion into sweeping tip motion, achieving high cutting efficiency while maintaining a straight needle configuration that provides excellent ergonomics and ease of operation during phacoemulsification surgery
3Productivity
If transverse steps or baffles are added to enhance cavitation and emulsification, then emulsification efficiency is improved, but the design was principally for longitudinal movement and does not work optimally with torsional ultrasound
Solution Approach 1:
The D-shaped asymmetric tip design inherently enhances cavitation and emulsification through its geometry rather than requiring additional transverse steps or baffles. The flattened posterior surface and curved anterior surface create optimal fluid dynamics and stress distribution that enhance emulsification efficiency while being specifically designed to work with torsional ultrasonic handpieces, providing both high productivity and adaptability
4Device complexity
If a standard round needle tip is used, then the design is simple, but it is easily blocked with incompletely emulsified lens material
Solution Approach 1:
The asymmetric D-shaped tip configuration with its flattened posterior surface and curved anterior surface creates superior emulsification that completely breaks down lens material, preventing blockage. The specific dimensional ratios (minor axis 0.4-0.6mm, major axis 0.6-0.8mm) and asymmetric geometry ensure that incompletely emulsified material does not form, maintaining reliable operation without clogging while preserving design simplicity
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 grooved needle tip design improves phacoemulsification efficiency, reduces clogging, and enhances fluid flow, allowing for more effective emulsification and better ergonomics during surgical procedures, including cataract removal and other tissue removal applications.
Implementation Method 1
inserting a needle tip vibrating at ultrasonic frequencies into the eye through a small corneal incision. As the vibrating needle tip and ultrasonic wave contacts the lens material it disintegrates and emulsifies it
Implementation Method 2
use transverse steps or 'baffles', or concave recesses within the mouth of the tip to enhance cavitation and emulsification
Data Source
Figure 1a~3
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Figure 7~10
AI summary
A needle (10) for a surgical instrument for removal of diseased or unwanted tissue is described. The needle (10) has a hollow elongate needle shaft (12) with a needle tip (14) at a distal end for cutting tissue. The needle tip (14) is flared in at least one plane and has a plurality of grooves (16) milled into a surface of the tip in an asymmetric arrangement around the circumference of the needle tip (14)..