Obstructive azoospermia is an azoospermia that occurs due to obstruction of the vas deferens that impairs the transport of sperm. Obstruction of the vas deferens is one of the important causes of male infertility, and obstructive azoospermia accounts for about 7% to 10% of male infertility patients. The proportion of obstructive causes is also higher in patients with azoospermia, at 42.4% to 48%.
. 1. Intratesticular obstruction accounts for 15% of obstructive azoospermia, with more acquired than congenital factors (causing dysfunction between the testicular network and the testicular output duct), and acquired factors such as inflammatory and traumatic obstruction, often accompanied by obstruction of the epididymis and vas deferens. Epididymal obstruction Epididymal obstruction is the most common cause of obstructive azoospermia. Congenital epididymal obstruction is often associated with congenital bilateral vas deferens (CBAVD), often with partial absence of the distal epididymis and spermatophore dysplasia. Other congenital causes are rare (impaired connection between the collecting ducts of the epididymis and the output ducts of the testis, partial hypoplasia or dysplasia of the epididymis). Congenital epididymal obstruction also includes Young’s syndrome, where the obstruction is mainly caused by fibrosis in the lumen of the proximal epididymal duct. Acquired epididymal obstruction is mainly from acute epididymitis (gonorrhea) and subclinical forms of epididymitis (e.g., chlamydia). Acute and slow trauma can also lead to epididymal injury. It can also be caused by surgical obstruction, such as epididymal cyst removal and surgical operation on the distal epididymis. 3. Vasectomy obstruction The most common cause of vasectomy obstruction is vasectomy due to birth control, and it can also occur after hernia repair. 3.1 Congenital obstruction Obstruction can occur anywhere in the vas deferens tract, from the testicular web, epididymis, and vas deferens up to the ejaculatory duct opening. CBAVD is the most common congenital vas deferens factor and is often a complication of fibrocystic disease. 3.2 Acquired obstruction Mainly genital infections, vasectomy, accidental surgical injury to the vas deferens in the inguinal region and inflammatory reaction around the vas deferens after the application of a patch in hernia repair lead to vas deferens obstruction.
3.3 Functional obstruction Any factor that interferes with nerve conduction in the vas deferens and bladder neck can lead to non-ejaculation or retrograde ejaculation, with common causes such as nerve injury and medications. 4. Ejaculatory duct obstruction Ejaculatory duct obstruction accounts for 1 to 3% of obstructive azoospermia. The two main causes are cystic and inflammatory, and cystic is usually congenital. 5. Functional obstruction of the distal sperm duct may be due to local neurological factors, due to smooth muscle weakness of the vas deferens or hypertonicity of the ejaculatory duct, and these abnormalities are associated with abnormal urinary flow dynamics. They can be observed in juvenile diabetic or polycystic kidney patients, but there is no pathological basis for sperm analysis findings of azoospermia, weak spermatozoa, or severe oligospermia.