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 greatly affects a man’s fertility since the sperm are essentially stuck in the testicles, with no way of reaching the urethra and exiting out of the body.

Symptoms

A complete lack of sperm in the man’s semen - a condition known as azoospermia - can be a symptom of this condition. The inability to conceive is another indication that a man may have a fertility issue such as bilateral absence of the vas deferens.

Cause

This condition is congenital, meaning that it exists at birth. The presence of CBAVD is strongly associated with cystic fibrosis. In fact, azoospermia and infertility are found in 95% of the males who survive to adulthood and CBAVD is common among these patients. In some cases, CBAVD may be the only feature suggesting an underlying mutation on the gene that causes cystic fibrosis. It is imperative that both partners are screened for cystic fibrosis, including a test for what is called the 5T polyvariant to be sure that they are not passing on CF to their offspring. Genetic counseling can help interpret the results. If both are found to be carriers, preimplantation genetic diagnosis (PGD) is an option.

Treatment

If the vas deferens are absent, surgery cannot correct the problem. However, there are surgical options to retrieve sperm form 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 and then IVF and ICSI can be used to assist fertilization. Intracytoplasmic sperm injection (ICSI) is the most common assisted reproductive treatment for couples where the male partner has CF and CBAVD.

Couples may also opt instead for the use of donor sperm.