• TESA: testicular sperm aspiration. This involves placing a needle attached to a syringe through the skin of the scrotum and simply sucking out the fluid inside the testicle.
• PESA: percutaneous epididymal sperm aspiration. This involves the same needle and syringe technique but the needle is placed directly into the epididymis.
• Perc biopsy: percutaneous biopsy of the testis. This is similar to TESA, but a larger needle is used.
• MESA: microsurgical epididymal sperm aspiration. An open surgical sperm retrieval procedure that uses an operating microscopy to locate the tubules of the epididymis precisely, so that large numbers of sperm can be extracted.
Surgical sperm retrieval techniques when there is no obstruction
Men who have no sperm in their semen, despite having clear tubes in their testicles, usually have a problem with the process of sperm production.
It is unlikely that sperm are present in large numbers, so the surgical sperm retrieval techniques required are more invasive.
• TESE: testicular sperm extraction. This involves opening up the scrotum and taking a large volume of testicular tissue, perhaps from several regions of the testicle.
• Microdissection TESE: a microdissecting microscope is used to pinpoint the tissue to be removed. This aims to cause less damage to the structure inside the testicle.