Outcome of Fowler-Stephens operation for undescended testes: an experimental study.

The aim of this study was the outcome of Fowler-Stephens (FS) operations in prepubertal Wistar rats. Thirty-two 30-day-old rats underwent laparoscopic FS procedures on the right testicles (8 of them formed the control group). Nine, 30, 70, and 90 days later we assessed the testes histologically and determined inhibin betaB serum concentrations; 1 day earlier, ultrasonography was also performed. Decreases in central testicular vascularity and heterogeneous parenchymal echogenicity were the initial sonographic evidence of testicular damage, which either regressed in time or extended toward the periphery. Early degenerative changes either remained mild and restricted in the germinative epithelium or became more severe, affecting additional structures. Decreases in the seminiferous tubule area, thickening of the tunica albuginea, and increases in the number of mast cells were changes that reached significance. Significant decreases in the amount of serum inhibin betaB were also found, and the decreases correlated significantly with both the thickening of the tunica albuginea and the increases in the number of mast cells but not with the decreases in the seminiferous tubule area. Division of the spermatic vessels caused severe testicular degeneration as evidenced by changes in ultrasonographic and histologic features combined with drops in the levels of serum inhibin betaB.