Azoospermia & surgical sperm retrieval (TESE/micro-TESE)

Azoospermia means that no sperm at all are detected in the semen analysis. It is one of the most severe forms of male infertility and affects about 10–15% of infertile men.

This diagnosis does not automatically mean there is no hope of fathering a child. In many cases, sperm are present inside the testis and can be retrieved surgically and used with intracytoplasmic sperm injection (ICSI).

What are the two main forms of azoospermia?

Obstructive azoospermia is due to a blockage somewhere along the path that carries sperm (for example after infection or surgery, or in congenital absence of the vas deferens). Here sperm production in the testis is normal; the sperm simply cannot get out.

Non-obstructive azoospermia is due to impaired or insufficient sperm production by the testes, from hormonal, genetic or other causes. Distinguishing the two forms is decisive, because it determines both the prognosis and the surgical strategy.

How are the two forms told apart?

The distinction rests on history, clinical examination (testicular size, palpation of the vas deferens), hormones (mainly FSH) and ultrasound. A high FSH with small testes points towards a non-obstructive form, while a normal FSH with normal-sized testes points towards an obstructive one.

No single test, however, is definitive; final confirmation often comes only at surgical exploration of the testis.

Why is genetic testing needed?

In non-obstructive azoospermia, genetic testing is essential before any surgical attempt. It includes a karyotype (for chromosomal abnormalities such as Klinefelter syndrome) and testing for Y-chromosome microdeletions, which directly affect the chance of finding sperm.

In obstructive azoospermia with absent vas deferens, the cystic fibrosis gene (CFTR) is tested. This testing has a dual importance: it identifies the cause and assesses the risk of transmission to the child, which is why it is always accompanied by genetic counselling.

What are TESE and micro-TESE?

TESE (Testicular Sperm Extraction) is the surgical removal of tissue from the testis to find sperm. In obstructive azoospermia, where production is normal, sperm are almost always found easily.

In non-obstructive azoospermia, the technique of choice is micro-TESE: using a surgical microscope, the surgeon identifies and selectively removes the tubules most likely to contain sperm. This raises the chance of finding sperm and removes less tissue than conventional TESE.

What is the chance of finding sperm?

In obstructive azoospermia, sperm retrieval is almost always successful. In non-obstructive azoospermia, micro-TESE finds sperm in about 40–60% of men, with considerable variation depending on the underlying cause and the centre.

Certain genetic conditions substantially change the prognosis: for example, microdeletions in the AZFa or AZFb region of the Y chromosome carry a very low chance of finding sperm. That is why genetic testing always precedes surgery.

What happens to the retrieved sperm?

Sperm retrieved from the testis cannot be used for natural conception or insemination; they are used exclusively with ICSI, where a single sperm is injected into the egg. Often part of the material is frozen for future cycles.

Ideally, the surgery is coordinated with the partner’s IVF cycle, so that fresh sperm are available on the day of egg retrieval. Close collaboration between the urologist–andrologist and the embryologist is decisive here.

Summary

Azoospermia — the absence of sperm in the semen — is divided into obstructive and non-obstructive forms, and this distinction determines the prognosis. Genetic testing (karyotype, Y-microdeletions, CFTR) is essential before any surgical attempt, together with genetic counselling. Micro-TESE finds sperm in about 40–60% of men with non-obstructive azoospermia, which are then used with ICSI. Azoospermia, therefore, does not automatically mean the end of hope for a biological child.

Sources: European Association of Urology (EAU), Guidelines on Sexual and Reproductive Health (Male Infertility); AUA/ASRM, “Diagnosis and Treatment of Infertility in Men” (Guideline).

⚕ Medically reviewed by Prof. Stratis Kolibianakis · Thessaloniki Medical Association Reg. No. 16340

ARTICLE 11 · MALE INFERTILITY