Preoperative Varicocele Severity and Sperm Concentration Are Associated with Absence of Internal Spermatic Vein Reflux in Patients Undergoing Varicocele Embolization: Results from A Cross-Sectional Study

Purpose: To assess the prevalence and predictors of absence of internal spermatic vein (ISV) reflux during varicocele embolization in infertile male. Materials and Methods: Demographic, clinical and laboratory data from 237 infertile males treated with percutaneous varicocele embolization between January 2017 and November 2024 were analyzed. Each patient underwent color Doppler ultrasound (CDUS) and semen analysis, both repeated 6 months post-procedure. Semen analysis values were based on 2021 World Health Organization reference criteria. Descriptive statistics and logistic regression models tested the association between predictors and embolization failure. Results: Median age was 28 (IQR 22-34) years. Median preoperative semen parameters included sperm concentration of 22 (10.0-44.5) x10(6)/mL, progressive motility of 35% (25%-40%), and normal morphology of 3% (2%-5%). Nearly half (48.9%) had CDUS grade >= 4 varicocele. Venous access was achieved via the right internal jugular vein in 46.4% and right common femoral vein in 53.6% of cases. Treatment was not performed in 1.3% of patients due to failure in catheterizing the spermatic vein and in 10.5% due to absence of ISV insufficiency duringValsalva. ISV reflux was more frequently absent in patients with grade III vs. grade IV-V varicocele (72.0% vs. 48.3%, p=0.02). After 2020, expert-driven ultrasound reduced the rate of phlebography-negative varicoceles (40% vs. 60%, p=0.03). Patients with confirmed varicocele had lower sperm concentration (20 x10(6)/mL vs. 26 x10(6)/mL, p=0.02). Grade III varicocele (OR 5.2; p=0.01) and higher sperm concentration (OR 1.1; p=0.03) were independent predictors of absent ISV reflux. Those with grade III varicocele and sperm count >20 x10(6)/mL had a 96% likelihood of reflux absence. Conclusions: Grade III varicocele and higher preoperative sperm concentration independently predicted the absence of ISV reflux, highlighting their role in patient selection. After expert-driven US implementation, the rate of no varicocele at phlebography significantly decreased.