Longitudinal genital growth curves in adolescents and Doppler‐based varicocele risk stratification

OBJECTIVES: To construct longitudinal ultrasound-based growth curves for genital development and to assess the prognostic value of varicocele grade and Doppler features. Varicoceles affect ~20% of adolescent boys and can be associated with impaired fertility. Evidence-based criteria for intervention are lacking due to limited longitudinal data. SUBJECTS, PATIENTS AND METHODS: We conducted a prospective longitudinal cohort study (2015-2021) of 570 boys aged 10.5-18 years (407 controls, 163 with left-sided varicocele; 1352 assessments). The boys underwent Tanner pubic hair staging (TSP), measurement of stretched penile length (SPL), and a scrotal ultrasound. The volumes of the left and right testes and total testicular volume (TTV) were calculated according to the Lambert formula. In varicocele, venous diameter (VD), spontaneous reflux (SR), peak retrograde flow (PRF), and clinical grade were measured. Growth trajectories were analysed using mixed-effects models. RESULTS: Severe subgroups (VD ≥3 mm, SR >20 cm/s, or Grade 3) had attenuated growth slopes and lower TTV at TSP 5 vs controls. Combined risk profiles (e.g., Grade 3 + VD ≥3 mm; SR >20 cm/s + Grade 3) showed the poorest outcomes, with final TTV consistently <30 mL. A PRF >38.4 cm/s alone was not predictive. The SPL differences were minimal. Some subgroups entered puberty earlier but progressed more slowly. Limitations include absence of semen and hormonal data, exclusion of atypical developmental disorders, and limited ethnic diversity. CONCLUSIONS: Most adolescents with a varicocele develop normally. Only those with combined high-risk Doppler and clinical features show impaired testicular growth. Doppler adds prognostic value beyond grade and supports a stratified surveillance strategy, potentially reducing overtreatment.