| 摘要 |
A needle 20 for use with a torsional or transverse ultrasound surgical phacoemulsification instrument comprises a hollow elongated needle body 22 having a needle tip 24 at a distal end for cutting lens material. The needle tip 24 is flared in one plane to produce a substantially elliptical tip mouth 26. The elliptical tip mouth 26 has a major axis 'X' larger than an outer diameter of the needle body and a minor axis 'Y' smaller than the major axis so as to form a spade-shaped tip. The eccentricity of the elliptical tip mouth 26 can be varied, however for practical purposes it is preferred that the major axis of the tip mouth is about 1.5 to 2.5 times longer than the minor axis. The spade-shaped tip 24 provides an improved cutting action, particularly with torsional ultrasonic vibration, the cutting action being analogous to that of a spade drill bit used in woodworking.
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