MESA or microsurgical epididymal sperm aspiration is a surgical procedure that is used to retrieve immature sperm from the epididymal tubules in men with vasal obstruction leading to absence of sperm in the ejaculate. MESA is a less invasive method of epididymal sperm retrieval compared to TESE (testicular epididymal sperm extraction), both of which involve cutting open the scrotum under general anesthesia in the operating room.
During MESA, a surgeon makes an incision in the scrotal skin to expose the testis and the epididymis. A specialized microscope is used to then open the epididymal tubules and aspirate sperm.
MESA has been shown to cause histomorphometric alterations of the testis and tubules as well as a significant increase in germ cell apoptosis. The ipsilateral testis of MESA patients showed more severe alterations than contralateral testes. TUNEL staining indicated a significant increase in spermatic granuloma formation and apoptosis in the testis after MESA.
A less invasive option of MESA is PESA or percutaneous epididymal sperm aspiration. With this procedure, a physician inserts a needle into the testicles and removes a sample of epididymal fluid, sperm, follicular cells and seminal fluid. The sperm is then washed in HEPES-buffered medium and centrifuged to separate the sperm from other tissue. Usually, the sperm is HOS tested and motile and/or cryopreserved for future IVF or ICSI cycles. IVF treatment using MESA or PESA sperm have success rates comparable to IVF/ICSI with fresh semen. Three couples have had live births after IVF-MESA-ICSI. mesa tesa