Outcomes and predictive factors of successful salvage microdissection testicular sperm extraction (mTESE) after failed classic TESE: results from a multicenter cross-sectional study

Microdissection testicular sperm extraction (mTESE) has been proposed as a salvage treatment option for men with a previously failed classic TESE (cTESE), but data are scarce. We aimed to assess the outcome of and potential predictors of successful salvage mTESE in a cohort of men previously submitted to unfruitful cTESE. Data from 61 men who underwent mTESE after a failed cTESE between 01/2014 and 10/2020, at 6 tertiary-referral centres in Italy were analysed. All men were investigated with semen analyses, testicular ultrasound, hormonal and genetic blood testing. Pathological diagnosis from TESE was collected in every man. Descriptive statistics and logistic regression models were used to investigate potential predictors of positive sperm retrieval (SR+) after salvage mTESE. Baseline serum Follicle-Stimulating hormone (FSH) and total testosterone levels were 17.2 (8.6-30.1) mUI/mL and 4.7 (3.5-6.4) ng/mL, respectively. Sertoli-cell-only syndrome (SCOS), maturation arrest (MA) and hypospermatogenesis were found in 24 (39.3%), 21 (34.4%) and 16 (26.2%) men after cTESE, respectively. At mTESE, SR+ was found in 30 (49.2%) men. Patients with a diagnosis of hypospermatogenesis had a higher rate of SR+ (12/16 (75%)) compared to MA (12/21 (57.1%)) and SCOS (6/24 (25%)) patients at mTESE (p < 0.01). No clinical and laboratory differences were observed between SR+ and SR- patients at mTESE. There were no significant complications after mTESE. At multivariable logistic regression analysis, only hypospermatogenesis (OR 9.5; p < 0.01) was independently associated with SR+ at mTESE, after accounting for age and FSH.In conclusion, salvage mTESE in NOA men with previous negative cTESE was safe and promoted SR+ in almost 50%. A baseline pathology of hypospermatogenesis at cTESE emerged as the only independent predictor of positive outcomes at salvage mTESE.