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Definition – What is a blocked vas deferens?

The spermatic duct (Ductus deferens) is a tube-shaped organ with strong musculature, 50 to 60 cm long, which is placed on both sides of the male body. It runs from the testicles or epididymis through the spermatic cord (Funiculus spermaticus) and combines with the ductus excretorius in the area of the bladder to form the “spiral canal” (Dutus ejaculatorius), which then opens into the urethra. A closure of the ductus defferens is usually the result of a vasectomy. When talking about the “blocked spermatic duct”, one usually means the closure of the ductus ejaculatorius, also called central closure.


Often the closure of the ductus ejaculatorius is congenital, which is caused by cysts in the so-called ducts. These play a central role in the development of the reproductive organs. Occlusion can also be caused by other congenital diseases, especially cystic fibrosis. However, an acquired obstruction can also be caused by inflammation of the prostate, which is usually caused by chlamydia. Another possible cause is an injury to the ductus ejaculatorius is the injury during an operation, for example during prostate surgery.


If the channel is only closed on one side, a diagnosis can be very difficult, because the other side can often compensate for the loss. However, if both sides are closed, this can be diagnosed primarily with a spermiogram. Here, a so-called azoospermia is noticeable, i.e. a lack of sperm cells in the ejaculate.

In addition, the ejaculate has a smaller volume or is completely missing, which is called aspermia. In the case of complete loss, the ejaculate then consists only of the secretion of the prostate. Procedures such as ultrasound and MRI are also used to confirm the suspicion.


Especially in the case of an incomplete or unilateral closure, patients often only become aware of an unfulfilled desire for a child. In this case, a spermiogram is always carried out, which then shows azoospermia. If the occlusion is more pronounced, a reduced sperm volume is noticeable, sometimes even aspermia, i.e. a “dry orgasm” can occur.

In addition, the occlusion can be shown by pelvic pain, the reasons for this are not yet fully understood. Whether the pain really comes from the Ductus ejaculatorius or another component of the seminal ducts cannot be determined as a patient, because the pain cannot be localized exactly. However, it is being discussed whether the occlusion can be the cause of unexplained pelvic pain, especially if it occurs in combination with infertility.


The closure of the ejaculatory duct can be treated by surgery, among other things. However, this is a relatively invasive method, which can lead to many complications, for example the backflow of urine into the seminal ducts. A more recent approach is balloon dilatation, in which a small balloon is inserted into the injection cannulae via a catheter in order to expand it.

Reproductive medicine is also a central component of the therapy, as there is often an unfulfilled desire for children. If the occlusion causes severe restrictions and pain or if there is an unfulfilled desire to have children, surgery should be considered. Your treating urologist will advise you on the options.