Obstructive Azoospermia

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Obstructive azoospermia (OA) is most commonly caused by vasectomy, with up to 6% (of the 600,000 men undergoing vasectomy yearly in the United States) ultimately choosing surgical reconnection (reconstruction) following vasectomy.  Other causes of obstruction are groin hernia repair (typically done during childhood), history of testicle/epididymis infection, or prior surgery to the testicle, epididymis, scrotum, or groin.  Patients can also be born with genetic abnormality/absence of the epididymis or vas deferens, both of which are part of the genital tract in which sperm mature and then pass through during ejaculation.  Gene mutations such as the cystic fibrosis gene are commonly involved with absence/obstruction of parts of the male reproductive tract.  A patient can have a mutation of the cystic fibrosis gene even if they do not have any symptoms (such as lung or pancreas problems) of cystic fibrosis.  If a man has CF mutation, it is important for his partner to be checked.  Men can also have blockage of the ejaculatory ducts (the last part of the tract where sperm pass before leaving the body) from cysts (which they are born with), prior surgery, or prior infection of the prostate.  Additional rarer causes are Young’s syndrome (normal sperm obstructed by abnormal secretions) and retrograde ejaculation (when ejaculation goes backward into bladder rather than out of the body).


Diagnosis of Obstructive Azoospermia:

At the Center for Male Health and Reproduction, Matthew Wosnitzer, M.D. specializes in diagnosis and treatment of obstructive azoospermia. Physical exam can help to diagnose abnormal anatomy of the testicle, epididymis, and vas (the tube that carries sperm from the testicle), as well as laboratory studies (including testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), semen analysis) and ultrasound of scrotum and/or prostate.  Patients with OA who are blocked typically have normal testicular function, normal testicular size, firmer testes and normal follicle-stimulating hormone (FSH).  NOA patients, by contrast, often have small testes which are soft and with elevated FSH levels.  For more information about the diagnosis and management of obstructive azoospermia, see one of Dr. Wosnitzer’s publications on this topic.


The treatment of choice for patients with obstruction includes vasectomy reversalwhich is microsurgical reconstruction (called “vasovasostomy” which means reconnection of the vas deferens after blockage removed) or “vasoepididymostomy” which means attachment of the vas deferens (with the blocked area removed) to the epididymis.  This allows for the vas deferens to be attached to the “good” part of the epididymis, avoiding a “bad” or obstructed portion of the epididymis.  Vasectomy reversal is the general term used to reconstruct the tract after vasectomy.  While the terms are a bit complicated, both are safe treatments with excellent outcomes to relieve vas or epididymis obstruction and to create “open pipes” without blockage and ultimately successful pregnancy of partner.   These procedures are done under a microscope because of the extremely small size of the channel in vas deferens (1/100 of an inch) and epididymis tubules (half the size of the vas deferens channel). For more detailed information about vasectomy reversal, see our additional posts on this surgical procedure.

An alternative to this would be sperm aspiration (preferably done by the urologic surgeon using a microscope) either from the testicle or epididymis (depending on the patient’s case) and cryopreservation or fresh sperm use in special procedures known as assisted reproductive technology (abbreviated ART).  The decision for surgical reconstruction or sperm retrieval with ART is based on numerous factors including number of children desired, male prior surgical history, prior fertility as a couple, female partner age, female factor infertility, religious beliefs, possibility for natural conception, and financial situation.

ART includes various techniques (in vitro fertilization (IVF)) to promote fertilization of selected sperm with an egg from the female partner (usually done outside the body with or without direct injection of sperm into the egg (intracytoplasmic sperm injection or ICSI first identified in 1992)).  The embryo (union of sperm with egg) is placed into its normal place in the female’s body (the uterus) where pregnancy should continue normally through birth.  The issue with IVF/ICSI is that it has been found to be less cost-effective than microsurgical reconstruction, and may carry an increased risk of birth defects with ICSI and possibly a small risk of mental retardation in children.  The ultimate decision between surgical reconstruction and ART is a personal one that depends on a number of factors that need to be discussed with your physicians.

We are pleased to discuss obstructive azoospermia further with you.  Please contact us for additional information and to schedule a consultation. For general male infertility background beyond obstructive azoospermia, see Male Infertility: All the Background Details.

Key Points
  • Obstructive azoospermia is caused by blockage of the male reproductive tract, most commonly following vasectomy.
  • Vasectomy reversal is an optimal treatment option in some men, while other cases may be treated with surgical sperm aspiration with IVF/ICSI.
Matthew Wosnitzer, M.D.