Semen parameters in adolescents with varicocele: association with testis volume differential and total testis volume

We evaluated the relationship between testicular volume differential, total testis volume and total motile sperm count in adolescents with varicocele. Prior reports have been inconclusive regarding the association of testis volume with semen analysis parameters.

We retrospectively reviewed a single institution database of Tanner 5 adolescents with nonoperated left varicocele with at least 1 semen analysis available. Patients were included in analysis if they had clinical left varicocele, ultrasound measurement of testis volume and no prior inguinal or scrotal surgery.

We analyzed the records of 100 patients. Mean ± SD age at presentation was 15.2 ± 3.5 years. The mean testicular volume differential was 8% ± 23% and 31 patients (31%) had a greater than 20% testicular volume differential. Mean total testis volume was 30.4 ± 13.3 cc. Varicocele was grade 3 in 39 patients, grade 2 in 50, grade 1 in 8 and ungraded in 3. Median total motile sperm count in the cohort was 42.0 (IQR 9.2, 105.8). ROC analysis with the Youden index indicated an optimal total testis volume cutoff of 30 cc to predict the total motile sperm count. In a multivariable logistic model accounting for age and varicocele grade a testicular volume differential of greater than 20% was associated with twice the odds of a total motile sperm count of less than 20 million per cc (OR 2.1, 95% CI 1.02-4.12, p = 0.04). Total testis volume less than 30 cc more than quadrupled the odds of a total motile sperm count of less than 20 million per cc (OR 4.2, 95% CI 1.8-9.7, p <0.001).

Total testis volume and the testicular volume differential are associated with semen analysis outcomes in adolescents with varicocele. A testicular volume differential of greater than 20% doubles the odds of a low total motile sperm count. A total testis volume of less than 30 cc quadruples the odds of a low total motile sperm count.