Prior vasectomy, congenital absence of the vas deferens (i.e. no sperm in the ejaculate but normal testicular sperm production, also referred to as obstructive azoospermia): IVF-ICSI with either Microsurgical Epididymal Sperm Aspiration (MESA) or Testicular Sperm Extraction (TESE).
With a MESA procedure, under local anesthesia and general sedation, an incision is made in the scrotum, exposing the epididymus, the tubules immediately adjacent to the testicles that collect the sperm. Using an operating microscope, an incision is made into these tubules and sperm is aspirated. Although millions of motile sperm can often be collected, this sperm has not acquired the ability to penetrate an egg and must be injected into eggs via the IVF-ICSI technique. The advantage of MESA over TESE for men with obstructive azoospermia is that sperm collected in this manner can usually be frozen, and even if his partner has to undergo more than one IVF procedure, the MESA should provide adequate sperm for all subsequent IVF procedures.