Microsurgical epididymal sperm aspiration (MESA)

What is it?

Azoospermia, a condition characterized by the absence of spermatozoids in the ejaculate, is found in 5% of couples wishing to become pregnant. Azoospermia can be secretory, that is characterized by the complete absence of spermatozoids caused by a primary pituitary or testicular insufficiency, or obstructive, due to the obstruction of the excretory ducts. Although azoospermia is associated with male infertility, it does not necessarily result in infertility because sperm production can be maintained at various levels within the testis. Therefore, several methods have been developed to recover spermatozoids from the epididymis or testis of infertile men, which can then be used to achieve pregnancy through medically assisted fertilization techniques.

Technical difficulty:
Average duration of the intervention:
1 hour
Average duration of hospitalization:
1 day

When is this procedure indicated?

Sperm retrieval, in patients with obstructive-type azoospermia, can be performed at the level of the epididymis, by a microsurgical (MESA) or transcutaneous (PESA) route.

How is it performed?

MESA can be performed under general or local anesthesia. After having identified and dissected the tunica vaginalis, by means of a 10x-40x magnification under the microscope, a micro-incision is made at the level of the epididymal serosa, initially highlighting the tubules at the level of the body and then, more and more proximally, up to the head. A sufficiently dilated tubule is selected and opened. The spermatozoids present inside are sucked by a special glass capillary with blunt tip. The collected material is immediately examined to assess the presence of spermatozoids, their motility and quality of progression. Usually it is necessary to take only a few ml, because the spermatozoids are highly concentrated in the epididymis.

If the sperm motility is not excellent, a new aspiration is performed by changing its position in a caudo-cranial sense: in fact, at the level of the head of the epididymis the spermatozoids with greater motility are usually found. The complete absence of spermatozoids, after repeated attempts, is an indication to perform the testicle sampling (TESE). The tubule is then sutured. The technique offers the advantage of being able to perform intratubular sampling under direct visual control, implement proper hemostasis and collect spermatozoids from multiple sites.


In the postoperative period, it is necessary to observe a period of rest and it is useful to apply ice at scrotal level.

Short-term complications

Scrotal pain that may require the use of pain medication. Other possible complications include edema, infection, and scrotal hematoma.

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