If there are no sperm cells in the sperm of the man, they can be obtained directly from the testes (TESE) or the epididymis (MESA). Then they can be used in an ICSI.
If no or too little sperm is detected in the semen (azoospermia or oligozoospermia), it may be possible to obtain sperm from the testicles or epididymis with a small operation. If removal is successful, artificial fertilization is possible - but only as part of an intracytoplasmic sperm injection (ICSI).
Careful diagnosis is a prerequisite. Above all, it is checked whether the sperm cannot enter the semen due to occlusion of the semen or whether their production in the testicles is disrupted. In rare cases, the vas deferens may also be missing due to a genetic disorder, such as cystic fibrosis. If there is a suspicion of hereditary causes, a human genetic counseling and possibly also a genetic examination is recommended.
If the semen passages are closed and it is not possible to get them through again surgically, it is possible to obtain sperm cells from the epididymis, in which the matured sperm cells are stored. The procedure is called Microsurgical Epididymal Sperm Aspiration (MESA). During the procedure, mobile sperm are removed from the epididymis under general anesthesia using a hollow needle (cannula). They are then frozen (cryopreserved) so that they can later be used for artificial insemination for ICSI.
If sperm production in the testicles is disturbed so that they form no or too few sperm, sperm can still be found in isolated areas of the testes. They can be obtained using a special surgical procedure called testicular sperm extraction (TESE). The procedure can also be used if it is not possible to obtain semen from the epididymis.
During the procedure, three or more tissue samples are usually taken on an outpatient basis and under local anesthesia. If there are sperm that can be fertilized, the tissue is frozen. As part of an ICSI treatment, the tissue is later thawed, the sperm are released and used for the artificial fertilization of the egg.
Unfortunately, it often happens that no sperm can be found using TESE. In such a case, the man is definitely sterile.
The usual anesthetic and surgical risks exist in both procedures. Bleeding, bruising and infection occur in rare cases.
After a TESE, one or both testicles may also shrink. In extreme cases, testicular death is also possible. Relatively often there is a temporary decrease in testosterone production.
The sperm obtained from TESE or MESA can only be used as part of an ICSI for artificial fertilization of the egg cell. This method of fertility treatment requires that the partner undergoes hormonal stimulation of the ovaries, which can put a lot of strain on her physically and mentally. Therefore, it should always be checked whether closed semen passages can be made operatively through. If this is successful, then natural fertilization is usually possible. If a man wants to become a father again after sterilization (vasectomy), it is also advisable to first examine whether the severed vas deferens can be connected again. A MESA or TESE should only be considered if this is not possible.