A study of the extent and pathology of experimental avulsion injury in rabbit arteries and veins.

A comparison was made between operating microscope observations and histopathological examination of the ruptured ends of experimentally avulsed rabbit femoral arteries and veins. Under the operating microscope no damage was evident in arteries or veins more than 0.8 cm (on average) from the rupture site, the common lesions being tears, holes, bruising, sleeving and dilatations. In light microscope and electron microscope studies arterial and venous lesions were often noted up to 4 cm from the rupture site both proximally and distally. Severe circumferential skip lesions involving the tunica intima and media in the arteries were noted, and commonly deep clefts also extended through all three tunicae at arterial bifurcations. In avulsed veins complete tears through all tunicae or partial loss of intima and media were observed. The extensive nature of these lesions is the most likely reason for the lower success rate of avulsed digits in replantation surgery.