Candidates for MESA

Candidates for sperm retrieval include men with acquired or congenital reproductive tract obstruction, and men who elect to undergo sperm retrieval as an alternative to surgical reconstruction. Acquired reproductive tract obstruction can occur as a result of infection, trauma, iatrogenic injury or previous failed vasovasostomy or vasoepididymostomy. Iatrogenic injury can occur during bladder neck, pelvic, abdominal or inguino-scrotal surgery.

Congenital anomalies of the male reproductive tract are relatively uncommon in the general population, but can occur in up to 2 percent of infertile men. Perhaps the best known congenital anomaly of the male reproductive tract is congenital bilateral absence of the vas deferens (CBAVD) which occurs in almost all men with cystic fibrosis. CBAVD is now regarded as most commonly reflecting a mild form of cystic fibrosis in which only the reproductive tract anomalies are manifest without pulmonary or digestive symptoms. CBAVD can also probably occur as a result of Wolffian duct anomalies without evidence of cystic fibrosis gene mutations. Unilateral vasal aplasia occurs in less than one percent of the male population and can also be associated with cystic fibrosis gene mutations.

In all cases of reproductive tract obstruction, the optimal treatment is one that will allow the couple to conceive with minimal intervention . When this is impossible (as in CBAVD) or has already failed (as in previous attempts at vasovasostomy or vasoepididymostomy) consideration must be given to the use of sperm retrieval directly from the epididymis or testis with assisted reproduction. Preferably, sperm should be retrieved and cryopreserved during attempts at reconstruction. Because of the association of CBAVD with cystic fibrosis mutations and Wolffian duct anomalies, all men with CBAVD should have renal ultrasounds and their wives should have cystic fibrosis gene mutation analysis prior to attempts at fertility.