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How many sperm need to be obtained in a testicular biopsy?

By Blanca Paraíso.
Last Update: 01/31/2020

About 30% of infertility cases are of male origin so it is very important to carry out the necessary diagnostic tests on both men and women to try to identify what the problem is when it comes to conceiving. Unfortunately, there are 10% of infertility cases that, despite current technologies and tests, are of unknown origin.

In the case of the man, among the possible problems that may exist is the total absence of sperm in the ejaculate or azoospermia.

If this situation occurs in an initial semen analysis, the patient will be asked for a hormone profile (testosterone and FSH) to check the functioning of the testicle. If the test is abnormal, it will be assumed that there is a problem in the functioning of the testicle and therefore in the production of sperm. This will require a more exhaustive study and everything points to the fact that the extraction of sperm directly from the testicle will not be viable or the result will be very scarce.

Otherwise, if the hormonal profile is normal, it will be due to a problem in the transport of these spermatozoa to their final destination. In this case, it is possible to resort to sperm extraction directly from the testicle with much greater guarantees of finding sperm.

There are different techniques which can be used to extract sperm from the testicle:

Percutaneus epididymal sperm aspiration
Microsurgical epididymal sperm aspiration
Testicular Sperm Aspiration
Testicular Sperm Extaction
(similar to the previous one but microsurgery is used to identify the best areas where mature sperm may be present while minimizing tissue damage)

Depending on the level of evidence from the different literature reviews, the choice of technique depends on the cause of azoospermia, with PESA, MESA, TESA, and TESE being the options with obstructive azoospermia and m TESE the best option for non-obstructive or secretory azoospermia.

To answer the question posed in the statement, it is necessary to define very well what these spermatozoa obtained from the testicle are going to be used for and what type of azoospermia we are talking about. In cases of secretory azoospermia, as it is more difficult to obtain sperm, an attempt can be made to perform microinjection even if the number is very low, always informing the patients of the prognosis. There is no defined minimum number of sperm but there must be at least two or three times the number of oocytes to be microinjected to ensure a certain margin of safety. Normally, freezing samples in these cases is very difficult due to the shortage.

In contrast, in obstructive azoospermia, the scenario is usually different. Embryologists assess that the concentration of sperm present is as before, 2-3 times more than the number of oocytes to be microinjected, and if the sample has a higher concentration it can be frozen for future use. As long as the sample can be frozen, it will be the most convenient to avoid future surgeries if the in vitro fertilization treatment fails.

The samples that give better results after ICSI are those where spermatozoa with some mobility are found or at least that has the minimum. This will indicate that the spermatozoon is alive and can give us correct fertilization.

If the initial motility is very low or nil, it is advisable to culture the testicular tissue for a few hours to try to find an increase in motility. If there is no motility at all, pentoxifylline can be used to reactivate the sperm, although it is necessary to centrifuge the sample to eliminate it before performing the microinjection.

In addition, it is important that they do not present significant morphological alterations.

Suggested for you: What Is a Testicular Biopsy? – Purpose & Procedure.

 Blanca Paraíso
Blanca Paraíso
MD, PhD, MSc
Bachelor's Degree in Medicine and Ph.D from the Complutense University of Madrid (UCM). Postgraduate Course in Statistics of Health Sciences. Doctor specialized in Obstetrics & Gynecology, and Assisted Procreation.
License: 454505579
Gynecologist. Bachelor's Degree in Medicine and Ph.D from the Complutense University of Madrid (UCM). Postgraduate Course in Statistics of Health Sciences. Doctor specialized in Obstetrics & Gynecology, and Assisted Procreation. License: 454505579.
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