The main methods of surgical sperm retrieval available include
MESA (MICRO SURGICAL EPIDIDYMAL SPERM ASPIRATION)
An open surgical retrieval procedure that uses an operating microscopy to locate the tubules of the epididymis precisely, so that large numbers of sperm can be extracted.
PESA (PERCUTANEOUS EPIDIDYMAL SPERM ASPIRATION)
A needle is passed through the scrotal skin and into the epididymis in order to aspirate sperm. Because the epididymal tubule is very delicate and convoluted, the yield with a needle is typically small and usually only sufficient for a single cycle of IVF-ICSI performed on the same day as the PESA.
TESA (TESTICULAR SPERM ASPIRATION)
A needle is passed through the scrotal skin into the testicle with syringe suction and numerous excursions of the needle through the testicular tissue, a very small amount of testicular tissue can be retrieved. In the case of poor sperm production, this technique may be performed through multiple entry points in the testicle in an effort to localize where sperm production may be occurring for subsequent open TESE.
TESE (TESTICULAR SPERM EXTRACTION)
Through a small skin incision, the testicle is explored. Small pieces of tissue are cut directly out of the testicles and sperm is extracted from this tissue by the embryologist. In cases of poor production, multiple excisions may be required to find an area containing sperm. In this situation, the sperm must typically be used within 24 hrs of retrieval .In a patient with a blockage, the sperm are plentiful enough to survive freezing of tissue for later use.
A similar technique but a micro dissecting microscope is used to pinpoint the tissue to be removed. This aims to cause less damage to the structure inside the testicle, and to therefore have fewer after effects such as blood supply problems caused by tiny blood vessels being cut. It also appears to increase the number of sperm that can be retrieved.