TESE and MESA are abbreviations for two surgical procedures used in men with deficient spermiograms. With these surgical procedures, sperm from either the testes (TESE) or epididymis (MESA) can be harvested for ICSI (Intracytoplasmic Sperm Injection). Learn here which operation helps when, and how it is ordered to the success of TESE and MESA.

What are TESE and MESA?

Since the beginning of the 90s, men with a poor spermiogram can be helped: Thanks to the ICSI, in principle only one fertile sperm cell is needed for successful fertilization. To detect these, the two techniques promise TESE and MESA. Because in about half of all apparently infertile men can be found in the testes still areas with spermatogenic activity.

The procedures are small operations on the testes or epididymis. MESA stands for microsurgical epididymal spermatozoa aspiration, ie epididymal puncture, and TESE for testicular spermatozoa extraction, ie an extended testicular biopsy.

A tissue-sparing, minimally invasive variant is the Mirko-TESE (microsurgical extraction of testicular tubular segments), which is preferably used in small testes. Following a TESE or MESA, artificial insemination (ICSI) can be performed.

How do TESE and MESA work?

MESA in the epididymis

In MESA, the epididymides are punctured with a fine needle (cannula) and the epididymal fluid is assayed for active mature sperm (epididymal spermatozoa). The procedure is performed under general anesthesia and with the aid of a surgical microscope. It is a bit more expensive than the testicular sperm extraction. Subsequently, the semen sample is stored by cryopreservation and processed shortly before ICSI.

TESE in the testicle

In TESE, testicular tissue is removed from one or both sides and examined. The surgery is outpatient and under local anesthesia or general anesthesia. About a small, about one to two centimeters long skin incision on the scrotum (scrotum), the surgeon exposes the testicles.

Subsequently, at least three small tissue samples are obtained and immediately examined in the laboratory. The further procedure depends on the laboratory results. If necessary, further biopsies are necessary. If active and fertile sperm are contained, the tissue is frozen. Only before the ICSI you can thaw the sample and remove the sperm. After completion of the TESE, the wound is closed with self-dissolving sutures and a compression bandage is applied to the scrotum. Afterwards the patient has to take a few days off and abstain from sex for one to two weeks.


In rare cases, a fresh TESE is possible, so without the intermediate step of freezing. Then, however, the artificial insemination must begin immediately afterwards. In this way, the costs of cryopreservation are eliminated and the risk of losing further sperm by freezing is reduced. However, it should be remembered that the woman may undergo an unnecessary hormone treatment to form fertilizable oocytes, if the man can find any fertile cells.

For whom are TESE or MESA suitable?

The reasons for a male fertility disorder are manifold: Pathological changes to testicles or epididymides such as varicose veins or testicle elevation, testicular cancer, Klinefelter syndrome or infectious diseases (mumps) can affect male fertility.

As a result of these disorders are often no sperm in the seminal fluid. Physicians then speak of azoospermia: either the man produces no or a small amount of sperm, that in the ejaculate no sperm can be detected (non-obstructive azoospermia) or the way for the seminal fluid is blocked (obstructive azoospermia).

In both cases, TESE and MESA can help, provided that healthy sperm can be found in the testicular tissue or epididymal fluid. Before that, it must be ensured that the partner can have an artificial insemination (ICSI).

In addition, the reason for the bad spermogram must be carefully examined before TESE and MESA. If the vas deferens are closed, an attempt should first be made to surgically restore patency (refertilvation operation). Incidentally, this also applies to men who still wish to have children after being sterilized. It may be possible to reconnect the severed vas deferens and natural fertilization becomes possible again.

The MESA is used primarily in occluded, non-reconstructible or missing sperm ducts or immobile sperm, as well as in non-treatable ejaculation disorder due to surgery or paraplegia.

TESE and MESA: chances of success

The chances of getting pregnant have increased significantly since the introduction of TESE and MESA and, ultimately, ICSI.

Whether the TESE will be successful, can be estimated on the basis of testicular size and the basal level of follicle stimulating hormone (FSH). Small testes and elevated FSH levels are unfavorable. In 60 percent of the cases, however, spermatozoa can be successfully obtained. The pregnancy rate is about 25 percent. With the Mirko-TESE, the tissue-conserving variant, the testosterone production can be increased by medication and thus the method can be optimized.

The success of MESA is independent of the number of acquired spermatozoa and the type of vas deferens. The pregnancy rate is around 20 percent.