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Believe it or not, there is a twenty-foot-long, thin-walled, tightly coiled duct within the scrotum that collects sperm from the seminiferous tubules, where sperm are manufactured, called the epididymis. It's a crescent-shaped duct that runs longitudinally along the back of the testis and as its walls become thicker and straighter it becomes the vas deferens. While sperm are passing through the epididymis, they mature and gain movement. In some men, the epididymis becomes blocked, preventing sperm from entering the vas deferens and getting into the ejaculate. A blockage can occur on either one side or on both sides. This blockage may be natural or may be caused by a hernia or hydrocele repair.
If a man has an epididymal obstruction on one side, he may suffer a lowered sperm count. If a man has epididymal obstructions on both sides, this will lead to azoospermia (a zero sperm count).
Your doctor can actually feel an epididymal obstruction when he performs a physical exam. During examination of the ductal structures, the epididymis may feel as though it is dilated and hardened. Generally, it is flat in the middle and cannot be felt. What this means is that if you have a dilated and hardened epididymis it may indicate a blockage.
If an epididymal obstruction is suspected in a man with no sperm in the ejaculate, you might have to undergo other tests to try and correct the problem. (Please refer to the section on azoospermia.)
If, after all the testing, your doctor tells you that he suspects an epididymal obstruction, the next step would be a testicular biopsy. A piece of the testis is taken either through an incision in the scrotum and testicle or with a needle. If good sperm production is found, then it is clear that production of sperm is not the issue, but the delivery of it into the ejaculate is. If other blockages are ruled out, a bypass of the blockage can be performed. This is called a vasoepididymostomy (because the vas deferens is reconnected to the epididymis.) As we've discussed in other sections, it's important that a skilled specialist, experienced with this type of surgery, perform this operation.
If the obstruction cannot be repaired, there are still options available. Sperm may be retrieved from the scrotum. This can be done in a number of ways. It can be done with a needle into the testis, or an incision in the testis. Most commonly a Microscopic Epididymal Sperm Aspiration (MESA) is done to get sperm from the epididymis. There are two advantages to this procedure over retrieval of sperm from the testis. The first is that the sperm are more mature, and thus usually have better movement (motility). The second is that there are significantly more sperm in the epididymis than the testis. This is because the ducts within the testis have collected the sperm already and delivered them into the epididymis. Often, the sperm retrieved through MESA can be frozen and used in multiple IVF cycles.
Sperm retrieved from the testis or epididymis may be used to attempt conception for couples using in-vitro fertilization (IVF) combined with intracytoplasmic sperm insertion (ICSI). IVF means that the eggs are retrieved from the woman. ICSI means that the sperm are injected directly in an egg.
A positive note here is that an epididymal obstruction does not mean you have untreatable infertility. There are a number of options available to patients suffering from the blockage. A male infertility specialist will be able to review treatment options with the patient and provide the greatest likelihood of success.