Azoospermia is defined by a complete absence of sperm in repeated semen analyses. In non-obstructive azoospermia (NOA) sperm production in the testicles is severely impaired or completely absent. Sperm can be recovered in approximately half of the men with NOA by microdissection testicular sperm extraction (MD-TESE), and many of these men can father biological children with intracytoplasmic sperm injection (ICSI) (Corona et al. 2019). Assisted reproduction techniques (ART) using these sperm seem to be as effective as other treatments performed for moderate or severe male infertility (Ravizzini et al. 2008). Predicting sperm recovery and the ICSI treatment results for an individual with NOA remains difficult, and refraining from offering the treatment is rarely relevant (Enatsu et al. 2016).

In Finland, MD-TESE operations were started in 2008 at Turku University Hospital (Tyks). From the first 100 operations, information was collected on the patients' diagnoses, previous procedures to find sperm, and the results and adverse effects of the operations. Sperm were found in 42 men. ICSI treatments with MD-TESE sperm and other ICSI treatments for moderate or severe male infertility in Tyks were compared, and the treatment results were similar in terms of fertilization, clinical pregnancy rate, live birth rate, gestational age at delivery and birth weight of the children born after ICSI.

In the magnetic resonance imaging (MRI) of the testicles, the apparent diffusion coefficient (ADC) value, which reflects the metabolism of the tissue, can be measured (Tsili et al. 2018). Twenty-one men presenting for MD-TESE and ten fertile control men MRI of the pelvis, and testicular ADC values were compared in different diagnostic groups and in relation to sperm retrieval. There were no significant differences in ADC values in relation to sperm retrieval success in MD-TESE or between different diagnosis groups, but ADC values in healthy controls were significantly lower than in men with NOA.

This study found that MD-TESE is an effective way to recover sperm and achieve biological parenthood for men with NOA, but for more than half of the men, no sperm production exists in the testis to enable successful sperm recovery. New methods of predicting sperm recovery are needed to avoid unnecessary operations.