Asymmetric D-Shaped Surgical Needle Tip for 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 their design limitations when used with torsional and transverse ultrasonic handpieces, leading to poor ergonomics and blockages during cataract removal procedures.
Innovation Solution
A hollow elongate needle tip with a flared, asymmetric mouth configuration featuring a flattened posterior lip and a curved anterior lip, creating a D-shaped or kidney-shaped tip mouth with serrations and chamfers, optimized for torsional and transverse ultrasonic handpieces to enhance cutting efficiency and aspiration flow.
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 ultrasonic handpieces, but it cannot effectively 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 lip and a curved anterior lip, creating an asymmetric tip mouth geometry. This asymmetry enables the tip to effectively interact with torsional and transverse ultrasonic handpieces by transforming the rotary needle motion into a sweeping or scything tip motion that efficiently breaks and emulsifies lens material, rather than simply coring it out as with symmetric round tips.
2Productivity
If a bent needle is used to transform rotary needle motion into sweeping tip motion for torsional ultrasound, then cutting efficiency improves, but the needle has poor ergonomics and is difficult to use during surgery
Solution Approach 1:
The invention applies local quality by modifying only the tip geometry of the needle while maintaining a straight shaft. The asymmetric tip configuration (flattened posterior lip, curved anterior lip) provides the sweeping motion effect locally at the tip, while the straight shaft preserves overall ergonomics and ease of manipulation during surgery, avoiding the poor ergonomics associated with bent needles.
3Productivity
If tip modifications such as transverse steps or baffles are added to enhance cavitation and emulsification, then emulsification efficiency improves for longitudinal movement, but the designs are limited and cannot work effectively with torsional ultrasound
Solution Approach 1:
The asymmetric tip mouth design (flattened posterior lip, curved anterior lip) creates a dynamic sweeping or scything motion at the tip during torsional or transverse ultrasonic operation. This dynamic motion adapts to the rotary movement of torsional handpieces, transforming it into an effective cutting and emulsification action, whereas static modifications like transverse steps or baffles are limited to longitudinal movement and cannot accommodate torsional motion.
4Ease of manufacture
If a standard bevelled tip is used, then the needle is simple to manufacture, but cutting efficiency is poor and the tip is easily blocked with incompletely emulsified lens material
Solution Approach 1:
The tip mouth is segmented into distinct functional zones: a flattened posterior lip for primary cutting and emulsification, and a curved anterior lip for secondary processing and material ejection. This segmentation allows incompletely emulsified lens material to be effectively managed and ejected, reducing blockage, while the overall geometry remains manufacturable through standard processes.
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 new needle tip design significantly improves cutting efficiency, reduces blockages, and enhances ergonomics by utilizing asymmetric serrations and chamfers, allowing for more efficient emulsification and fluidics, while minimizing thermal side effects and improving visualization during surgical procedures.
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
AI summary
A needle 10 for a surgical instrument for removal of diseased or unwanted tissue comprises a hollow elongate needle shaft 12 having a needle tip 14 for cutting tissue at a distal end of the needle shaft 12. The needle tip 14 is flared in at least one plane and has a flattened posterior lip 16 and a curved anterior lip 18 to produce a substantially D-shaped tip mouth 20 in a plane that is substantially orthogonal to a central longitudinal axis C—O—C′ (the needle axis) of the needle 10. A major axis A-A′ of the tip mouth 20 is larger than an outer diameter of the needle shaft 12 and a minor axis B—B′ is smaller than the major axis A-A′. The asymmetry of the tip mouth provides improved cutting action during phacoemulsification.