[Transrectal ultrasonography in the etiological diagnosis of male obstructive azoospermia: analysis of 695 cases].

OBJECTIVE: To assess the role of transrectal ultrasonography (TRUS) in the etiological diagnosis of male obstructive azoospermia. METHODS: We retrospectively analyzed the clinical data and TRUS findings of 695 patients with obstructive azoospermia from January 2007 to May 2009. RESULTS: Concerning the etiology of obstructive azoospermia, the main TRUS findings included ejaculatory duct abnormality (29.2%), seminal vesicle abnormality (25.4%) and prostate midline cyst (18.5%). TRUS revealed 203 cases of ejaculatory duct dilation, 177 cases of seminal vesicle abnormality (including 108 with absence or agenesis and 51 with dilation of the seminal vesicle), and 128 cases of prostate midline cyst (including 75 with ejaculatory duct cyst and 39 with Müllerian cyst). Calcification of the verumontanum or ejaculatory duct was suspected to be the causes of obstructive azoospermia in 34 cases. However, no significant etiological abnormality was found in 153 cases. Obvious etiology was shown by TRUS in 78.0% of the patients. CONCLUSION: TRUS can clearly display the structural abnormality of the ejaculatory duct and seminal vesicle, and provide important information on the etiology of male obstructive azoospermia.