Effects of spermatic vascular division for correction of the high undescended testis on testicular function. Orchiopexy with division of the spermatic artery and veins is a commonly used technique for correcting the high undescended testis, although the longterm results have not been clearly defined. The left spermatic artery and veins of 22 adult Wistar albino rats were divided while preserving the vessels associated with the vas and cremaster muscle (DT). A sham operation was performed on the left testicle of six additional rats (ST). At 3 weeks postoperatively, both testes from all rats were removed. All testes were viable and bled when incised, although bleeding was considerably reduced in testes with DT. Mean testicular weights after DT were 1,061 +/- 423 mg compared with 1,634 +/- 125 mg for ST rats (p less than 0.02) and 1,508 +/- 119 mg for contralateral testes. The mean tubular diameter after DT was 220 +/- 37 mu compared with 303.1 +/- 10.7 mu for ST testes (p less than 0.02). The testicular biopsy score based upon the morphology of the spermatic tubules was 4.46 +/- 3.32 for DT testes and 8.65 +/- 0.23 for ST testes (p less than 0.02) compared with 8.38 +/- 0.18 for contralateral testes and an absolute normal value of 10. No morphologic abnormalities were observed in the contralateral unoperated testes from any of the rats. The contralateral testes in 12 additional rats were removed before DT. The mean testosterone values in these rats with one testicle was 1.43 +/- 0.75 ng/mL. Three weeks after DT, testosterone values were 0.19 +/- 0.31 ng/mL (p less than 0.01). It is concluded that division of the main spermatic artery and vein in rats produces testicular atrophy with spermatogenic arrest and interstitial cell dysfunction. Although collateral blood flow to the testis may be demonstrated, tissue perfusion is inadequate for normal spermatogenesis and endocrine function. 