Sperm selection and subsequent microinjection techniques, such as IMSI and/or PICSI, have not demonstrated any superiority to the usual ICSI technique. For this reason, their use in routine clinical practice is not recommended at present.
The PICSI technique, which stands for Physiological Intracytoplasmic Sperm Injection (PICSI), means "Physiological ICSI". The procedure is based on trying to select a sperm that is physiologically apt to fertilize an oocyte and allow normal embryonic development, for which the selection is made by exposing the sperm to substances similar to those found on the surface of the oocyte and assessing their compatibility. However, it has not been demonstrated that its use leads to better results and adds another step to the ICSI process, which could even be detrimental to the technique, in addition to the fact that the exposure of the spermatozoa to exogenous substances could lead to undesired and not always risk-free results.
PICSI has not been the only technique used to try to increase the performance of ICSI, but there have been others. It is worth mentioning the IMSI technique (Intracytoplasmic Morphologically Selected Sperm Injection, also known as "Super-ICSI"), in which a high magnification microscope (6,000 X) was used to select a morphologically perfect spermatozoon. However, since it has not been shown to be superior to classic ICSI, and taking into account the high costs involved in its application, it is currently in disuse.
