In cases of azoospermia, spermatozoa are obtained from the testicles. However, depending on the causes of azoospermia, there is a distinction between obstructive and non-obstructive azoospermia, there is a production of spermatozoa in the testes; nevertheless it is impossible for them to be exported to the sperm during ejaculation, since there is a barrier present at some point along the reproductive tract. In the case of non-obstructive azoospermia, the absence of spermatozoa is due to spermatogenesis problems in the testes and is the most severe form.
All methods for the collection of spermatozoa from the testicles are combined with the application of ICSI, since both the number and the mobility of spermatozoa are reduced, after they have been taken from the testicles. We also ought to point out that the quality of spermatozoa from the testes or from epididymis is bad, a fact which may affect the result of the IVF attempt.