Testicular arterial blood flow volume in predicting semen improvement following microscopic subinguinal varicocelectomy.

Background: Varicocele is a significant but treatable contributor to male infertility. The efficacy of varicocelectomy in improving sperm quality is not consistent, with only 60-80% of patients experiencing improved semen quality. This prospective cohort study aimed to evaluate the effect of microscopic subinguinal varicocelectomy (MSV) on testicular arterial blood flow volume (TABFV) and to determine the value of preoperative TABFV in predicting the outcome of MSV. Methods: Patients with varicocele who underwent MSV at the same clinical center between July 2020 and April 2023 were enrolled. All patients underwent ultrasound assessment and at least one semen analysis before and after MSV. Both univariate and multivariate logistic regression analyses were performed to assess the association between pre-MSV variables and semen improvement after MSV. Subsequently, a diagnostic model was developed. Results: This study enrolled 96 patients with varicocele, including 31 who showed semen improvement after MSV and 65 who did not. The postoperative semen-improved group demonstrated a significant increase in TABFV of the right testis (TABFV-R) and left testis (TABFV-L) (P<0.001). Notably, the postoperative TABFV-L was more than twice the preoperative TABFV-L. Preoperative TABFV-R and a combination of subclinical right-sided varicocele were found to be associated with semen improvement after MSV, and a diagnostic model was developed using these two variables. The diagnostic model exhibited satisfactory performance, with an area under the curve (AUC) of 0.824 [95% confidence interval (CI): 0.735-0.913], which was further validated internally yielding an AUC of 0.824 (95% CI: 0.726-0.900). Additionally, calibration analysis confirmed that the diagnostic model was well calibrated, and the Hosmer-Lemeshow test resulted in a P value of 0.794. The decision curve demonstrated that using this proposed nomogram would yield a net benefit if the threshold probability for semen improvement after MSV exceeded 10%. Conclusions: TABFV-L demonstrated potential utility in clinical practice for assessing outcomes of MSV, and the diagnostic model incorporating TABFV-R and a combination of right-side varicocele performed well in predicting improvements in semen parameters following MSV.