What is the difference between TESA, TESE, MESA, PESA?
Sometimes, during ejaculation, although men produce seminal fluid, a semen analysis test can reveal the absence of sperm in this ejaculated semen sample. The presence of fructose is an indication that there is sperm production; albeit due to some blockages in tubes or other reasons, the sperm may not be present in the ejaculate and this may lead to one of the causes of male infertility. However, all hope of conceiving and having a successful pregnancy is not lost, as there are certain procedures available to patients where sperm can be retrieved from their site of production, ie., the testis. These procedures vary slightly and are commonly known as Sperm Retrieval Procedures (SRP).
The above terms – TESA, TESE, MESA and PESA refer to various methods of SRP.
TESA (Testicular sperm aspiration) is a method of TESE (Testicular sperm extraction) performed by needle insertion in the testis, drawing out fluid and tissue by a vacuum (negative pressure). This tissue is then processed and the extracted sperm cells are used for ICSI (Intracytoplasmic sperm injection) where one sperm is directly injected into the egg, or IVF (in vitro fertilization) where the egg and sperm (multiple in number) are left in a petri dish to fertilize on their own.
MESA: In conditions such as obstructive azoospermia (the absence of spermatozoa in the ejaculate), a technique known as MESA (Microsurgical Epididymal Sperm Aspiration) is used. This involves incision of a single tubule by dissecting the epididymis. The fluid that overflows from the epididymal tubule is then drawn out. This method, because of the vast number of vessels in the epididymis, sometimes leads to contamination by blood cells that may affect sperm fertilizing capacity in IVF.
PESA (Percutaneous Epididymal Sperm Aspiration): With this method, no surgical incision is required. A small needle is passed through the skin of the scrotum directly into the head of the epididymis and the fluid is drawn out.
The epididymis is a long coiled tube that stores and carries sperm from the testes to the ductus/vas deferens in the male reproductive system. As it passes through the epididymis, the sperm matures so that it is ready to fertilize the female cell by the time it enters the ductus/vas deferens.
Once the fluid is aspirated in all the above techniques, the embryologist collects the sperm cells and prepares them for ICSI or IVF.
Three main goals should be accomplished during sperm retrieval:
(i) the acquisition of an adequate number of sperm for both immediate use and cryopreservation (the process of freezing and storing embryos),
(ii) retrieving the topmost quality of sperm,
(iii) minimizing the damage to the reproductive tract, thus preserving the option of future retrieval attempts and testicular function.
The choice of which type of SRP to use will depend upon the nature of azoospermia, which can be obstructive (OA), or non-obstructive (NOA), which is a consequence of spermatogenic failure. Treatment of patients with NOA is only limited to attempting TESA. One important point to note is that, no matter what method is used, not all men will be found with sperm in the testes.
The recovery procedure after sperm retrieval is usually quick. In the case of PESA, patients usually start normal activities on the following day. For the other treatments, patients are usually advised a 48 hour bed rest and application of an ice-pack to the scrotum. They are instructed to resume a normal diet and to get back to their activities within 3-4 days. The patient should keep away from exerting himself with sports activities, lifting weights and sexual intercourse for about 2 weeks.
With the advanced techniques of SRPs, men are now able to overcome the inability to have biological children.
