Adolescent varicocele-is the 20/38 harbinger a durable predictor of testicular asymmetry?

Part of the management of adolescent varicocele is trying to prognosticate who with testicular asymmetry will have catch-up growth with observation and who will have persistent asymmetry. We previously reported that catch-up growth is rare when peak retrograde flow greater than 38 cm per second is associated with 20% or greater asymmetry (ie the 20/38 harbinger). We sought to determine if this 20/38 cutoff held true with a larger series, and what peak retrograde flow value should be used when 15% instead of 20% asymmetry is chosen as the cutoff.

We analyzed patients from our large varicocele registry who had undergone at least 2 duplex Doppler ultrasounds and had been observed for at least 10 months in the interim. Outcomes were determined regarding those who met the 20/38 cutoff and what peak retrograde flow value could be used to recommend surgery when 15% to 19.9% asymmetry was included in the cutoff value.

Of 355 adolescent boys with left varicocele 44 (mean age 14.0 years, range 9 to 20) were followed with observation initially and met the 20/38 cutoff, while 9 additional patients met the 15/38 cutoff (initial asymmetry 15% to 19.9%). When combining both groups, only 3 boys had catch-up growth to less than 15% on followup. Thus, 50 of 53 patients did not demonstrate catch-up growth after a mean followup of 15.5 months (range 10 to 44).

Not only does a peak retrograde flow of greater than 38 cm per second hold up for predicting persistent/worsening asymmetry when combined with a 20% asymmetry cutoff, it also is an excellent predictor of persistent and/or worsening asymmetry when combined with a 15% asymmetry cutoff. Therefore, it might be unnecessary to follow an adolescent boy with observation who is at or above this 15/38 cutoff.