The usefulness of a piezo-micromanipulator in intracytoplasmic sperm injection in humans

Intracytoplasmic sperm injection (ICST) has wide clinical application, In o rder to achieve good results with this method, it is important to restrict the possibility of oocyte injury as much as possible, and securely inject s permatozoa into the ooplasm, For this purpose, we clinically applied piezo- ICSI, which employs a micromanipulator with piezoelectric elements, to huma ns, and compared the results with those obtained by conventional ICSI, Conv entional ICSI and piezo-ICSI were used in 279 cycles and 335 cycles respect ively. Piezo-ICSI showed significantly more favourable results, with a surv ival rate of 88.1% (conventional ICSI: 81.4, P < 0.001), a fertilization ra te of 79.4% (conventional ICSI: 66.4%, P < 0.001), and a pregnancy rate of 23.1% (conventional ICSI: 14.9%, P < 0.05). In piezo-ICSI, the needle used is not sharpened and has a hat tip. However, deformation of the oocyte duri ng insertion of the needle is restrained by vibration of the piezo, and the oolemma is punctured readily and securely by the piezo pulse, at the site where the spermatozoon is injected. Piezo-ICSI is a promising new technique for human ICSI that should improve the survival, fertilization and pregnan cy rates after ICSI.