AN EXPERIMENTAL-MODEL OF NEONATAL TESTICULAR TORSION - EVIDENCE AGAINST AN EXCLUSIVELY EXTRAVAGINAL ETIOLOGY

The present study was designed to determine whether extravaginal torsi on of the spermatic cord (EVT) can be distinguished from intravaginal torsion (IVT) on the basis of gross and histologic examination of the testis. It is traditionally believed that EVT, postulated to occur onl y in neonates, can be grossly distinguished from IVT, which occurs in older patients, on the basis of adherence between testis and tunica va ginalis. Such adherence is felt to be present in EVT but not IVT. This concept that the two types of torsion can be distinguished in the ope rating room has important clinical ramifications. In cases of EVT, con tralateral orchidopexy theoretically need not be performed, since adhe sions develop between tunica vaginalis and dartos by a few weeks of ag e. This is in contrast to IVT, in which contralateral orchidopexy is n ecessary due to the bilateral nature of the bell clapper deformity. Us ing a rat model, we first demonstrated that IVT could produce adherenc e of the tunica vaginalis to testis. Then, eight rats were operated on , producing right IVT and left EVT. Animals were then sacrificed at in tervals of up to one month. Gross and histologic examination showed in volvement of the tunica vaginalis in an ischemic and inflammatory resp onse in a majority of testes, regardless of the type of torsion. Attem pts to distinguish EVT from IVT on the basis of grossly evident adhesi ons between tunica vaginalis and testis are of questionable validity. Early contralateral orchidopexy is therefore recommended in all cases of neonatal torsion.