Partial obstruction of the male ductal system: fact or fiction?

Andrologists sometimes experience difficulty deciding if a patient is azoospermic because of obstruction or because of testicular failure to produce sperm. When the testicular biopsy reveals that relatively small numbers of mature sperm are being produced, azoospermia may be the clinical manifestation of this condition. However, some patients who have ductal obstruction also have decreased levels of testicular sperm production ("hypospermatogenesis"). This discussion will concern: (a) the evidence that partial ductal obstruction may exist; (b) the clinical manifestations of partial ductal obstruction; (c) methods of diagnosis of partial ductal obstruction; and (d) treatment of partial ductal obstruction.