Predictors for successful sperm retrieval of salvage microdissection testicular sperm extraction (TESE) following failed TESE in nonobstructive azoospermia patients

The purpose of this study was to observe the clinical utility and the possible determinants in predicting sperm retrieval of salvage microdissection testicular sperm extraction (mTESE) for nonobstructive azoospermia (NOA) patients with failed conventional TESE at their first attempts. A total of 52 NOA males underwent salvage mTESE were recruited in this study. Related data, including age, BMI, the presence of Klinefelter's syndrome and varicocele, cryptorchidism, mean testicular volume, hormonal profile (total testosterone (TT), follicle-stimulating hormone (FSH), luteinising hormone (LH), inhibin B (INHB)), testicular histology and surgical duration, were collected and analysed. A multivariate logistic regression with likelihood ratio test revealed the following predictors of sperm retrieval: TT and testicular histology (chi-square of likelihood ratio=26.42, df=4, p<.005). A formula was also established using multivariate regression analysis in predicting sperm retrieval probability. A predicted probability of more than 71% was determined of the formula as the cut-off value in predicting sperm retrieval using receiver operating characteristics (ROC) analysis with a sensitivity and specificity 78.0% and 72.4% respectively. In conclusion, salvage mTESE is of clinical value in NOA males with failed TESE attempts, whereas the established formula could be useful in determining the proper salvage mTESE candidates.