MESA

Microsurgical Epididymal Sperm Aspiration (MESA) is a sperm extraction procedure, in which sperm from the patient is obtained from the epididymis, a tube at the back of the testicle that stores and carries sperm. If the epididymis itself is blocked or absent, sperm can be extracted from the testicles. MESA is often used for men with no sperm in their semen due to a blockage or an absence of the vas deferens (the tube which leads from the testes). These men may be producing sperm in large numbers, but due to the blockage or absence of the vas deferens, none is seen in the semen. This condition is similar to men who have had a vasectomy.