In cases where a diagnosis of azoospermia has been made and there is a blockage of the ducts, microsurgical epididymal sperm aspiration (MESA) and percutaneous testicular sperm aspiration (TESA) techniques are used to retrieve sperm. The MESA procedure involves the retrieval of sperm under a microscope from the coiled channels of the epididymis (the structure located behind the testis that serves to store and transport sperm) under either general or local anaesthesia. The TESA procedure, on the other hand, involves the search for sperm by performing a sperm aspiration from within the testis using a syringe after the testis has been immobilised under local anaesthesia.

The preferred method for azoospermic men in whom sperm production problems are identified in the absence of ductal obstruction is the microdissection testicular sperm extraction (mTESE) method. Under general or local anaesthesia, a small incision is made in the testicular tissue under a microscope, and samples are taken from dilated sperm ducts in an attempt to retrieve sperm.

