| 摘要 |
A method and apparatus are provided for removing tissue, such as cataractous lens tissue, using ultrasonic energy. The apparatus includes a working tip and a transducer or the like for applying ultrasonic vibrations to the working tip. A vacuum source is provided for aspirating fluid through the working tip. The working tip includes a relatively large diameter opening for admitting relatively large tissue fragments. The opening adjoins a bore portion of relatively large diameter. The working tip further includes a bore portion of relatively small diameter and large wall thickness for breaking the tissue fragments into smaller pieces. The method according to the invention includes the steps of moving the end of the working tip into engagement with body tissue, vibrating the tip to cause the body tissue to break into fragments, aspirating fragments into the relatively large diameter portion of the bore, and causing the fragments to pass through the relatively small diameter portion of the bore such that the fragments are efficiently broken into smaller fragments. The end of the working tip may be slotted and the sleeve surrounding the working tip may have a first end portion extending substantially to the end of the working tip and a second end portion terminating well before the end of the tip.
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