A New Assisted Hatching Technique Using a Piezo-Micromanipulator 1 Takahiro Nakayama, Hiroshi Fujiwara, Keiji Tastumi, Kazuyuki Fujita, Toshihiro Higuchi, Takahide Mori  Fertility and Sterility  Volume 69, Issue 4, Pages 784-788 (April 1998) DOI: 10.1016/S0015-0282(98)00017-X

Fig. 1 The procedure of assisted hatching by the piezo-micromanipulator. (A), The ZP of human IVF embryos was carved in a narrow area by the vibration of an ICSI needle with a fine spike, which was produced by the piezo-micromanipulator unit. (B), The assisted hatching procedure was applied to adjacent sites of the ZP. One third of the visible circumference of the ZP was thinned, and a reduction of >75% of the original thickness was obtained. (C), Complete breaking of the ZP was performed, and a hole 20 μm in diameter was created in the thinned zona. (D), A hatching embryo at 2 days after the treatment. The apparent natural thinning of the zona cannot be seen, but a large hole developed at the thinning site of the zona, which enabled the embryos to complete the hatching process without entrapment. Fertility and Sterility 1998 69, 784-788DOI: (10.1016/S0015-0282(98)00017-X)

Fig. 2 Effects of the embryo quality at assisted hatching on the rates of hatching or of hatched embryos per developed blastocysts. ∗P <0.001 vs. control; †P <0.05 vs. control; ‡P <0.05 vs. grade-3 quality embryo. Fertility and Sterility 1998 69, 784-788DOI: (10.1016/S0015-0282(98)00017-X)