From histopathology to clinical success: Johnsen score as predictors in micro-TESE outcomes of idiopathic non-obstructive azoospermia

Background

The purpose of our study was to explore the influence of Johnsen score on the sperm retrieval outcome (SRO) in idiopathic non-obstructive azoospermia (iNOA) patients treated with micro-TESE.

Methods

Data were collected and analyzed from a single reproductive center using a retrospective cohort study design, involving 265 male patients with iNOA who underwent microdissection testicular sperm extraction (micro-TESE) between January 2017 and December 2024. The associations between SRO and Johnsen score were investigated through univariate and multivariate logistic regression analyses, supplemented with stratified subgroup assessments. Receiver operating characteristic (ROC) curve analysis and decision curve analysis (DCA) were performed to evaluate the predictive performance of the Johnsen score-based model for successful SRO probability.

Results

Among 265 iNOA patients undergoing micro-TESE, successful SRO were achieved in 108 cases (40.75 %), while 157 patients (59.25 %) showed negative surgical outcomes. Multivariate logistic analyses showed iNOA patients with higher Johnsen scores of testicular tissues obtained during micro-TESE were more likely to have successful SRO, this trend did not change after stratifying by age, body mass index (BMI), testis volume (TV), and testosterone (T). FSH and LH stratification revealed differential predictive capacity: significant association in FSH < 22.29 or LH< 8.55 IU/L subgroups versus null effect in FSH≥ 22.29 or LH≥ 8.55 IU/L cohorts. The predictive performance evaluation demonstrated that the Johnsen score-based nomogram achieved an area under the curve (AUC) of 0.69 in per-patient analysis, with corresponding sensitivity and specificity values of 56.9 % and 74.9 %, respectively. Decision curve analysis further confirmed the clinical superiority of this composite model, showing significantly greater net benefit across threshold probability ranges (30–85 %) compared to isolated Johnsen score assessment.

Conclusion

While Johnsen scoring provides a quantitative histopathological assessment of testicular spermatogenic function and demonstrates significant association with sperm retrieval outcomes (SRO), its standalone predictive capacity for micro-TESE success in idiopathic non-obstructive azoospermia (iNOA) patients remains suboptimal, necessitating integration with clinical parameters to establish a robust prognostic model.