Definition - What does Obstructive Azoospermia mean?
Obstructive azoospermia is the absence of sperm in semen due to a blockage in the tubes of the male reproductive system that carries sperm from where they are produced in the testes to the urethra. Conditions such as infection, surgery, injury or developmental abnormalities can lead to obstructions of the tubes, blocking sperm from entering the semen during ejaculation. Patients with obstructive azoospermia is a known cause of male factor infertility.
FertilitySmarts explains Obstructive Azoospermia
Sperm cells that develop in the testes travel through the vas deferens and the ejaculatory duct to come out during ejaculation. The vas deferens begins at the epididymis of the testis and it opens to the urethra through the ejaculatory duct.
A blockage in the male reproductive tract can be caused by an infection, injury or rarely due to abnormalities during the development of the tubes that result in either incomplete or absent vas deferens from birth. Males who undergo a vasectomy, the surgical procedure to achieve sterility, also have type of obstructive azoospermia, and cannot fertilize an egg unless they have vasectomy reversal surgery.
When a male patient who is evaluated for infertility and shows to have low or zero sperm counts, a testicular biopsy is usually done to see if there is a defect in the production of sperm. If the biopsy is normal, obstructive azoospermia is suspected and a vasogram is performed by injecting a dye to the vas deferens to locate the exact place of the blockage in view of corrective surgery.
In some patients, the blockage may be correctable with surgery. If surgery is not appropriate or fails, they can resort to assisted reproductive methods which have a high success rate as their testes produce functionally normal sperm.