Establishment of predictive variables associated with testicular sperm retrieval in men with non-obstructive azoospermia

Although testicular biopsy for sperm extraction is a procedure with a poten tial for complications, sperm retrieval is successful in 30-70% of patients with non-obstructive azoospermia, In order to predict the probability of r etrieving at least one testicular spermatozoon we conducted a prospective s tudy of a set of variables in 40 patients with non-obstructive azoospermia, Using the receiver operating characteristic curves, we determined the prob ability estimates of testicular volume, plasma follicle stimulating hormone (FSH) concentration, Johnsen score and visualization of testicular spermat ids in discriminating between patients with successful and failed testicula r sperm extraction. Visualization of testicular spermatids provided the bes t estimate of success of testicular sperm extraction. Of the factors studie d using logistic-regression analysis (age, maternal and paternal age at bir th, body mass index, luteinizing hormone, testosterone, FSH, testicular vol ume, the presence of testicular spermatids and Johnsen score), only the pre sence of spermatids and Johnsen score were independent variables able to pr edict the success of testicular sperm extraction, The visualization of the presence of spermatids gave a correct prediction of 77% and Johnsen score o f 71%, The diagnostic model derived from these independent predictors when validated in 40 patients using the Jackknife technique gave a correct overa ll prediction of 87%, The probability of successful testicular sperm extrac tion in patients with non-obstructive azoospermia could be objectively pred icted on the basis of simple histopathological criteria represented by the visualization of testicular spermatids and Johnsen score.