bilateral absence of the vas deferens
The vas deferens is a long, tube-like structure that connects the epididymis (the site of sperm storage) to the urethra (the tube that expels sperm). During ejaculation, the sperm flows out of the testicles, through the vas deferens and into the urethra, which leads outside the body through the penis.
Congenital bilateral absence of the vas deferens (CBAVD) is a condition present from birth in which the vas deferens is missing. This significantly affects a man’s fertility since the sperm are trapped in the testicles, with no way of reaching the urethra to exit the body.
symptoms
A complete lack of sperm in the man’s semen -- azoospermia -- can be a symptom of this condition. The inability to conceive is another indication that a man may have an infertility problem such as bilateral absence of the vas deferens.
cause
This condition is congenital, meaning that it exists at birth. Up to 65% of men with CBAVD are cystic fibrosis carriers. 40% of men with CBAVD may actually have a mild form that only presents itself as CBAVD. It is imperative that both partners are screened for cystic fibrosis, including a test for what is called the 5T polyvariant to be sure they do not pass CF on to their offspring. Genetic counseling is indicated in these cases so the couple understands the risks. If both are found to be carriers, preimplantation genetic diagnosis (PGD)is an option. Preimplantation genetic diagnosis (PGD) can determine which embryos carry the disease so that only healthy embryos are chosen for transfer.
treatment
If the vas deferens are absent surgery cannot correct the problem, however there are surgical options to retrieve sperm from the body. MESA (microsurgical epididymal sperm aspiration) is a procedure that retrieves sperm from the epididymis. A testicular biopsy can also be performed to retrieve sperm for use in IVF and ICSI to assist fertilization. Intracytoplasmic sperm injection (ICSI) is the preferred assisted reproductive treatment.
Couples may opt instead to use donor sperm.