Following male orgasm, sperm are ejaculated after traveling rapidly in sequence through the vas deferens duct, the prostate gland, and the urethra. The vas deferens must be patent to allow the passage of sperm in the ejaculate.
Causes of total obstruction of the vas deferens:
- Primary occlusion: Congenital (Bilateral) Absence of the Vas Deferens (CBAVD): In some cases men are born with occlusion of the vas deferens, obstructing the free passage of sperm in the ejaculate.
- Acquired blockage of the vas deferens. In this situation, the duct is open at birth but becomes blocked following an acquired insult such as vasectomy, failed vasectomy reversal, blunt trauma, and infection. The condition of total obstruction of these ducts is diagnosed when a man who has hormonally, functioning testes (normal blood FSH/LH levels) has absolutely no detectable sperm in his ejaculate (azoospermia). Physical or ultrasound or laboratory examination will help determine the cause.
About CBAVD and its relationship to Cystic Fibrosis: It is important to be aware that there is a known association between the autosomally recessive inherited genetic condition of cystic fibrosis (CF) and CBAVD. CF is a highly debilitating and life-endangering condition that predominantly affects the lungs and pancreas. Nearly all men with cystic fibrosis have CBAVD, while male carriers for CF, although otherwise seemingly healthy, also have an increased risk compared to those men who carry no abnormal genes.
Treatment: Fertility treatment of total obstruction of the vas deferens, involves egg retrieval with in vitro fertilization (by intracytoplasmic sperm injection-ICSI) using surgically harvested sperm. The sperm is most commonly obtained through two (2) possible procedural approaches:
- Percutaneous Epididymal Sperm Aspiration (PESA), does not require a surgical incision. A small needle is passed directly into the head of the epididymis through the scrotal skin and fluid is aspirated. The embryologist retrieves the sperm cells from the fluid and prepares them for ICSI.
- Microsurgical Epididymal Sperm Aspiration (MESA) is used in conditions like obstructive azoospermia, involves dissection of the epididymis under the operating microscope and incision of a single tubule. Fluid spills from the Epididymal tubule and pools in the Epididymal bed. This pooled fluid is then aspirated. Because the epididymis is richly vascularized, this technique invariably leads to contamination by blood cells that may affect sperm fertilizing capacity in vitro.
- TESA and TESE: TESE or testicular sperm extraction is a surgical biopsy of the testis whereas TESA or testicular sperm aspiration is performed by inserting a needle in the testis and aspirating fluid and tissue with negative pressure. The aspirated tissue is then processed in the embryology laboratory and the sperm cells extracted are used for ICSI.
The use of MESA/TESE with ICSI renders IVF/ET just as successful when applied in cases of sperm duct obstruction as when conventional IVF/ET is done. The procedures are simple to perform, relatively low-cost, safe, and the risk of complications is small. Although not very incapacitating, MESA is a more painful and procedure than TESA which is virtually pain-free. In fact, most men can literally take off a few hours for the TESA procedure and thereupon return to normal activity. One of the advantages of MESA is that unlike percutaneous TESE which needs to be repeated each time IVF is performed, a single MESA allows for the collection, freezing and storage of sperm for subsequent use.