Method, which uses a laser to identify viable sperm cell for subsequent ICSI, recommended in MESA/TESE IVF cycles and any other cases of immotile spermatozoa.
Sperm viability is a prerequisite for a successful ICSI treatment, because the injection of a nonviable spermatozoon into an oocyte generally results in fertilization failure. To identify viable sperm in patients presenting with complete sperm immotility is a challenging but very important step. Using LAISS a single laser shot is applied close to the tip of the sperm tail using a non-contact 1.48 µm diode laser system. In a few seconds, two possible reactions can be observed:
- either the tail of the spermatozoa starts curling after the laser shot, or
- the spermatozoa show no reaction at all.
Spermatozoa showing a curling reaction are considered to be viable and can be used for ICSI treatment immediately. In contrast to another methods e.g. hypo-osmotic swelling test, the laser selection can be performed directly in IVF medium with no additional micromanipulation.
LAISS is regarded as a safe procedure since a shot applied to the far end of the flagellum does not affect the sperm head containing the genetic material. Moreover, this novel technique used in a specific group of patients increase the chance to select viable spermatozoa capable of fertilization.