Percutaneous epididymal sperm aspiration (PESA) is a sperm retrieval technique used to extract spermatozoa from males with an obstructive azoospermia diagnosis. Azoospermia indicates there is an absence of sperm, or a sub-fertile level of motile sperm in the seminal fluid. In many cases, men with an obstruction still produce sperm in the epididymis.
Located behind the testes, the epididymis is the site of sperm production and storage. In non-obstructive fertile males, the spermatozoa enter the vas deferens, where they travel to the urethra and into the seminal fluid. During PESA, sperm retrieval is possible without putting the patient through the trauma of an open micro-surgical procedure. PESA is commonly used in combination with intracytoplasmic injection (ICSI) techniques, however, it may also be used to aspirate sperm for cryopreservation.
Candidates for PESA
PESA may not be suitable for men diagnosed with non-obstructive azoospermia because the infertility is not caused by structural abnormality. Candidates for PESA include men who are unable or choose not to undergo reconstructive surgery following vasectomy. PESA may also be recommended for patients having reconstructive procedures. Sperm retrieved during reconstruction may be cryopreserved in the event the reconstruction proves unsuccessful.
Additional candidates for PESA include patients diagnosed with congenital bilateral absence of the vas deferens (CBAVD) and those who carry the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Other candidates include men who suffer from structural abnormalities or obstructions caused by birth defect, trauma, surgery or illness.
In the past, PESA procedures were performed using general anesthetic. Today, it is routinely performed with local anesthesia and sedation. After the patient has been properly prepared and anesthetized, the urologist inserts a small gauge butterfly (winged) needle through the scrotum and into the epididymis. The surgeon gently manipulates the fine needle until a small amount of epididymal fluid is aspirated into the syringe.
Once fluid is detected, a smaller syringe containing a culture medium is attached to the tubing of the needle to collect additional fluid. This collected fluid is transferred to another tube, where a specially trained technician prepares a sample for examination. Using a high-powered microscope, the technician records the number of viable sperm found in the sample. If sufficient amounts are not detected, the procedure is repeated until adequate numbers of motile sperm are retrieved. Multiple retrieval procedures are not uncommon.
The aspirated sperm are put into a special solution to wash away any immotile sperm, tissue cells or blood. Additional processing is needed if a female partner is scheduled for ICSI. Collected sperm not used during ICSI may be cryogenically preserved.
Most patients will experience some pain and discomfort for a few days to a week following the procedure, which is usually managed with over-the-counter analgesics. In rare cases, discomfort may persist for up to 2 weeks following surgery. Patients are able to return to work within one to two days if they do not engage in strenuous physical activity or heavy lifting.
PESA Risks and Complications
PESA is the least invasive of sperm retrieval techniques, but there are risks of infection and bleeding. Hematoma caused by a puncture in a vein is also possible. Patients should also be aware there is a chance that no sperm will be retrieved.