Why is azoospermia classified as obstructive or non-obstructive?
Although azoospermia can be due to genital tract obstruction, defective spermatogenesis, ejaculatory duct dysfunction or hypogonadotrophism, it is currently classified as obstructive and non-obstructive. This is because hypogonadotrophic azoospermia and ejaculatory duct dysfunction are rare causes of azoospermia, accounting for about 2% of azoospermia (Hull et al., 1985). Defective spermatogenesis in 60% and genital tract obstruction in 40% of 102 patients with azoospermia evaluated with testicular biopsy and distal vasography were reported (Matsumiya et al., 1994). None of the patients in this series had ejaculatory dysfunction or hypogonadotrophic hypogonadism. Out of the 96 consecutive patients with azoospermia evaluated at Sheffield, 58% had defective spermatogenesis, 31% genital tract obstruction, 7% had features likely to be associated with retrograde ejaculation and 3% were of endocrine origin (unpublished data). Most of the endocrine causes of azoospermia have usually been addr
