Sperm Retrieval Procedures For Men With Obstructive Azoospermia

Men can experience infertility for many reasons such as having little to no motile sperm in their ejaculate, blockages that prevent the delivery of sperm or a surgically removed vas deferens (VAS). Thankfully, sperm retrieval procedures such as PESA and TESA allow men with obstructive azoospermia to improve their fertility.
Testicular Aspiration

TESA, or Testicular Fine Needle Aspiration (TFNA) is used to obtain sperm in men who have a blockage preventing sperm from leaving the testis and reaching the semen. This is commonly seen in men who have a vasectomy they choose not to reverse and men with congenital bilateral absence of the vas deferens.

During this procedure the testicle is numbed with local anesthetic and a needle is used to aspirate a small amount of fluid and tissue from one or both of the testicles. The sperm is assessed under the microscope and either cryopreserved for future use or used to fertilize an egg.

This procedure is a surgical alternative to PESA and is performed with a thin needle inserted into the scrotum via the scrotal skin and tunica albuginea. This is an ideal technique for men who have a swollen epididymis and is often done in conjunction with MESA. A sperm sample can be obtained from the proximal epididymal head, or from the body or tail of the epididymis.
Percutaneous Epididymal Sperm Aspiration (PESA)

With a needle inserted into the scrotum, the doctor aspirates epididymal fluid that contains sperm. The procedure is performed under local anesthesia.

A thorough analysis of the patient’s medical history is crucial. It helps us identify any underlying conditions or previous treatments that may impact the success of PESA.

Unlike TESA, which requires a needle aspiration of the seminiferous tubules that usually contain immature or non-motile sperm, PESA uses a simple needle to collect epididymal fluid containing motile sperm. It is less invasive and produces comparable pregnancy rates with ICSI.

In a series of 79 PESA procedures, motile sperm were retrieved in 98% of the cases. The rate of successful fertilization, cleavage and implantation with the cryopreserved spermatozoa from PESA is comparable to that of TESA and significantly higher than electroejaculation. Moreover, PESA allows sperm to be cryopreserved and saved for future use in ICSI without the need for further procedures such as a fresh ejaculation.
Surgical Epididymal Sperm Aspiration (MESA)

Surgical epididymal sperm aspiration (MESA) involves careful incision or excision of the overlying tunic at x15-x20 magnification in order to expose the epididymal tubules. Sperm-containing fluid is then aspirated from optimal locations of the epididymal tubes using a micropipette under vision at high magnification. This procedure is usually performed under a general anesthetic and requires extensive microsurgical skills. It can retrieve far greater numbers of sperm than TESA and is especially useful in men with obstructive azoospermia who are not well served by needle aspiration or vasectomy reversal.

MESA can yield thousands or even millions of moving sperm in ideal candidates and has been shown to produce superior fertilization and pregnancy rates compared with ICSI using testicular sperm. These results have led to its adoption as the standard technique for sperm retrieval in patients with CBVAD and vasectomy. However, it is important to note that MESA can only be used for intracytoplasmic sperm injection. Therefore, it is not appropriate for those looking to have children by natural means or who are interested in having a surrogate.
Cryopreservation

Since ancient times it has been known that biological material can be preserved at low temperatures. However, the biological and chemical reactions that occur at these low temperatures cause significant physicochemical damage to living cells and tissues that can be lethal. These damaging events include the formation of extracellular and intracellular ice crystals, the osmotic stress associated with water-to-ice phase change, toxicity from cryoprotectants, and cooling injury that occurs as a result of the transition from liquid to solid state.

Vitrification, a flash freezing process that eliminates the formation of ice crystals, can significantly reduce these lethal effects of low temperature. In addition, nonpermeable cryoprotectants such as trehalose can reduce the need for wash steps that are often time-consuming and expensive. This approach has allowed en bloc cryopreservation of stratified neural retina (NR) epithelia derived from human iPSCs and the preservation of morphologically normal photoreceptor precursors. It has also been shown to be effective in preserving alginate-encapsulated hepatocyte spheroids for hepatocellular transplantation.pesa mesa tesa