MESA
MESA (microsurgical epididymal sperm aspiration) is an open surgical sperm retrieval technique whereby the scrotum is opened up and the epididymis is visualized under an operating microscope. The aim is to achieve optimal selection of individual epididymal tubules in order to retrieve a higher number of sperm cells with better quality. Once an epididymal tubule has been selected under the microscope, it is punctured by a micropuncture pipette (250 to 350 μm tip size) and the sperm inside it is aspirated.