Microsurgical Epididymal Sperm Aspiration – MESA

Microsurgical Epididymal Sperm Aspiration (MESA): An incision is made through the scrotal skin. Using optical magnification, the tiny epididymal tubules can be incised and sperm rich fluid aspirated. A large number of motile sperm is typically retrieved and it can be used immediately for intracytoplasmic injection into an egg, or can be frozen in several batches for delayed or subsequent cycles of IVF-ICSI should they be necessary.

MESA is a very effective procedure for obstructive azoospermia because it usually yields high numbers of sperm for IVF. Epididymal sperm usually freezes well; therefore, after MESA, it is possible that you will not have to undergo additional procedures for subsequent IVF cycles if enough sperm are collected.
During this outpatient procedure, and while you are under anesthesia, your physician will make a small incision in the skin of the scrotum. MESA relies on an operating microscope to isolate the epididymis and locate the tiny epididymal tubules storing the sperm. An epididymal tubule is opened and its fluid examined for sperm. If present, both the fluid and sperm are removed and processed in the laboratory. If none or very few are found, additional tubules are opened. Once they are examined, the tubules are closed and any sperm that are not needed for IVF, and meet certain criteria, are frozen and stored in the laboratory.

MESA or microsurgical epididymal sperm extraction refers to a surgical procedure designed to extract sperm directly from the epididymis for use in an IVF
cycle. MESA is most often perfomed in individuals with no sperm in their ejaculate due to a blockage in the epididymis or vas deferens. The blockage might
have resulted from previous hernia repair or vasectomy; from epididymitis or orchitis; or from a condition known as congenital absence of the vas deferens in which a portion of the male reproductive tube is missing.
In the procedure, dilated epididymal tubules are exposed with the assistance of the operating microscope. Several tubules are selected and then
punctured with specially designed micropipettes attached to an aspiration device. Each micropipette will hold approximately 20 million sperm. Therefore,
approximately 100 to 150 million sperm can be collected and cryopreserved from one aspiration attempt. These pipettes are cryopreserved for later
use in an IVF/ICSI cycle.
The advantages of the microsurgical epididymal sperm aspiration compared to a percutaneous biopsy are 1) large numbers of sperm obviate the need for future sperm retrieval techniques, (2) less injury to the epididymis and testis, and (3) better quality specimens for cryopreservation.
Sperm retrieved from a MESA procedure are used in a procedure called ICSI or intracytoplasmic sperm injection. The sperm can be fresh or frozen. In a fresh cycle, eggs from the female partner are retrieved on the morning of the MESA procedure. The sperm retrieved in MESA are then injected directly into the mature eggs within approximately six hours of retrieval. Any remaining sperm are cryopreserved for a later cycle if necessary.
In a frozen cycle, the frozen sperm are thawed the morning of the female partner’s retrieval, and then injected into her mature eggs within six hours of
thaw. At most centers, fresh or frozen sperm extracted in a MESA procedure have equivalent fertilization rates.
Follow-up after MESA includes an office visit at one month to check the incisions, hormone studies at three and six months, and a scrotal sonogram at six months to check that the testes have healed.