If the sperm count is too low or there is a negative result of a sperm test, TESA/TESE represent possible options. In the case of blocked vas deferens or of a congenital bilateral absence of the vas deferens, or if there are no spermatozoa present in the ejaculate, the semen can be retrieved from the testicles or epididymis by means of a minor surgical procedure.
In the case of testicular sperm extraction (TESE), a small piece of testicular tissue is obtained by means of surgery and the spermatozoa are extracted from it; these can then be used for PICSI.
This technique can be employed in cases of the following conditions:
Testicular sperm aspiration (TESA) is less invasive than TESE and can be used, for example, if there is blockage of the vas deferens.
The subsequent preparation in the embryology laboratory serves to sort out spermatozoa of a poor quality. The healthy spermatozoa undergo the crucial maturation process and are therefore capable of fertilisation.