A fine needle is used with a biopsy gun to remove small lengths of seminiferous tubule (sperm producing tubules). These are then carefully dissected under a microscope by
embryologists
Testicular sperm aspiration is performed by inserting a needle into the testis and aspirating fluid and tissue using negative pressure. The sample is then processed to extract the sperm cells in the embryology laboratory using the ICSI or Intracytoplasmic sperm injection.
The sperm cells need not have to be mature and pass through epididymis to fertilize an egg. Since the testicular sperm is immature, they need ICSI, a technique in which a single sperm is taken from the semen and injected directly into the egg.
TESA can give some discomfort for a few days as it’s a slightly complex procedure. It is done under local anesthesia or sedation as per the patient’s preference in day care no need of any hospital stay. If TESA doesn’t provide enough sperm, testicular biopsy is needed in such cases.
Much speculations and concerns have been raised about the use of genetic material from a developing sperm cell. Also, there can be a chance that the cause of infertility can be transmitted to the progeny.