What are TESE and MESA?
Since the beginning of the 90s, men with poor spermiogram can be helped: Thanks to Intracytoplasmic Sperm Injection (ICSI), since then only one fertilizable sperm cell is needed in principle for successful artificial insemination – this is injected directly into the egg cell in a test tube with a fine needle. But what can be done if the man’s sperm contains no or too few sperm cells that can be obtained for ICSI?
In such cases, TESE or MESA may be able to help: These are minor surgical procedures through which sperm cells are collected directly from the testicle or epididymis.
- TESE stands for Testicular Sperm Extraction (basically an extended testicular biopsy).
- MESA stands for microsurgical epididymal sperm aspiration, which is the extraction of sperm from the epididymis.
A tissue-sparing minimally invasive variant is the Mirko-TESE (also M-TESE, microsurgical extraction of testicular tubular segments), which is preferably used for small testicles.
Following TESE or MESA, artificial insemination by ICSI can then be performed.
How do TESE and MESA work?
MESA: focus on the epididymis
TESE: Testicles in focus
In TESE, testicular tissue is removed from one or both sides in an outpatient procedure and examined for suitable sperm cells. The man receives local or general anesthesia for this procedure. The small operation proceeds in detail as follows:
The surgeon exposes the testicle through a small incision about one to two centimeters long in the scrotum. He then takes at least three small tissue samples and sends them to the laboratory for analysis. with self-dissolving suture material and applies a pressure bandage to the scrotum.
In the laboratory, the testicular tissue samples are analyzed for active and fertilizable sperm. If they are found, the tissue is frozen (cryopreservation). Shortly before ICSI, the frozen testicular tissue is thawed and the sperm are collected.
After TESE, the patient must rest for a few days and abstain from sex for one to two weeks.
Fresh TESE
In rare cases, fresh TESE is also possible, i.e. without the intermediate freezing step. In this case, however, artificial insemination must begin immediately after the procedure. In this way, the costs of cryopreservation are eliminated and the risk of losing sperm through freezing is reduced.
For whom are TESE or MESA suitable?
There are many reasons for male fertility disorders. For example, pathological changes in the testicles or epididymis such as varicocele or undescended testicles, testicular cancer, Klinefelter’s syndrome and testicular damage due to mumps can impair male fertility.
As a result of these disorders, there are often no sperm at all in the seminal fluid. Doctors then speak of azoospermia: either the man produces no sperm or such a small amount of sperm that no sperm can be detected in the ejaculate (non-obstructive azoospermia) or the pathway for the sperm 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. Beforehand, it must also be ensured that the partner can be artificially inseminated by means of ICSI.
MESA is primarily used in cases of blocked, unreconstructable or missing vas deferens and immobile sperm. It is also suitable for men with untreatable ejaculatory dysfunction due to surgery or paraplegia.
TESE and MESA: chances of success
The chances of pregnancy have increased significantly since the introduction of TESE and MESA and ultimately ICSI.
Whether TESE will be successful can be estimated by testicular size and basal levels of follicle-stimulating hormone (FSH). Small testes and elevated FSH levels are unfavorable. However, spermatozoa can be successfully obtained in 60 percent of cases. The pregnancy rate is about 25 percent. With Mirko-TESE, the tissue-sparing variant, testosterone production can be increased with medication, thus optimizing the method.
The success of MESA is independent of the number of spermatozoa obtained and the type of vas deferens occlusion. The pregnancy rate is about 20 percent.
Advantages and disadvantages of TESE and MESA
TESE and MESA are minor surgical procedures. Therefore, there are the usual risks associated with anesthesia and surgery: infections, bruising, swelling, or postoperative bleeding may occasionally occur.
The advantage of TESE and MESA is obvious – the chance to obtain fertilizable sperm cells despite a deficient spermiogram and to conceive a child with the help of ICSI. Theoretically, only one potent sperm cell is sufficient for this purpose. Overall, TESE and MESA are relatively safe, effective and largely tissue-sparing microsurgical procedures.
