TESA or testicular sperm aspiration is performed by inserting a needle in the testis and aspirating fluid and tissue with negative pressure. The aspirated tissue is then processed in the embryology laboratory and the sperm cells extracted are used for ICSI.
PESA or Percutaneous Epididymal Sperm Aspiration (PESA), does not require a surgical incision. A small needle is passed directly into the head of the epididymis through the scrotal skin and fluid is aspirated. The embryologist retrieves the sperm cells from the fluid and prepares them for ICSI.