PESA/MESA
What is it?
They’re both procedures with the purpose of extracting sperm directly from the epididymis (place that stores the sperm, in where it is nourished and through which it is later transported) to use it in IVF / ICSI when it can’t be collected from the ejaculated fluid.
Both PESA (Percutaneous epididymal sperm aspiration) and MESA (Microsurgical Epididymal Sperm Aspiration) are used to aspirate fluid from the epididymis, but the way they are implemented differs.
How is it done?
Although it may technically vary, PESA aims to aspirate epididymal fluid in a percutaneous way (skin puncturing). During the surgery, a thin needle attached to a syringe is inserted in the epididymis, passing through the scrotal skin, allowing fluid extraction. The collected material is then analyzed to see whether the amount of sample is enough and has a satisfactory sperm quality for IVF / ICSI or not.
MESA, unlike PESA, has an open (literally) approach and makes use of microsurgery; therefore, it’s more complex. During the surgery, an incision is made in the scrotum, exposing the semen conducting tubes. With the assistance of a microscope, it’s possible to identify where is the highest concentration of seminal fluid to be extracted. The collected fluid is then analyzed to see if it matches the proper conditions to be used in IVF / ICSI.
Whom should do it?
Both techniques are recommended to non-obstructive azoospermic men, including the ones that passed through vasectomy, since in both situations only the sperm passage is prevented, not its production.
Besides that, there may also be inborn sperm obstructions, such as agenesis (absence) of vas deferens, cysts in the ejaculation ducts and epididymal obstructions. These sperm obstructions can also happen because of epididymis and prostate genital infections, or because of urethra, prostate or bladder surgeries.