Sperm retrieval is the technique by which sperm are obtained from the testes or epididymis when there is a congenital absence of the vas deferens, a failed vasectomy reversal, inadequate sperm production, or obstruction--conditions which cause the absence of sperm or azoospermia.
MESA, PESA, and TESE
One method is called micro epididymal sperm aspiration (MESA). The surgeon makes an incision in the scrotum and gathers sperm from the epididymis, a duct that the body uses to mature, store, and pass sperm (through the testes).
Percutaneous epididymal sperm aspiration (PESA) is similar to MESA but does not employ microsurgery. In PESA, the physician uses a needle to penetrate the scrotum and epididymis, so that he can draw sperm into a syringe.
One more technique, known as testicular sperm extraction (TESE), involves the removal of a minuscule amount of testicular tissue, from which some few viable sperm cells may be collected. This process is used to retrieve sperm from men with impaired sperm production, or when MESA is unsuccessful.
All of these procedures are done with a local anesthetic and take about 30 minutes to perform. These procedures may cause pain and swelling.
Give it a Whirl
Next, the sperm is washed in a procedure that helps to isolate and prepare the healthiest sperm for the purpose of insemination. Both sperm and washing solution are placed in a centrifuge and spun. This achieves the separation of the sperm from white blood cells and fatty acids (prostaglandins) that are components of semen but may hinder the mobility of the sperm. The process also concentrates the sperm, increasing the probability of conception.
After the sperm is retrieved by MESA, PESA, or TESE, it can be used in in vitro fertilization (IVF) or in intracytoplasmic sperm injection (ICSI).
In IVF, eggs and sperm are combined under laboratory conditions to produce embryos which are then transferred into the uterus.
Intracytoplasmic sperm injection (ICSI) is helpful in achieving conception with immotile sperm, or sperm that are incapable of movement. This technique can be used in combination with in vitro fertilization. The specialist uses a very fine glass needle to inject a sperm into a mature egg that has been retrieved. The egg is then incubated and transferred to the uterus.
Though extra sperm obtained through MESA or PESA can often be frozen for future use, most of the sperm derived through the TESE procedure are not viable for frozen storage because they are not of sufficient quality or quantity for cryopreservation. It is not recommended to undergo these procedures multiple times since such repetition can lead to scarring of the tissues.