Acute ischaemic neuropathy in the rabbit.

Ligation of either the common and internal iliac or the internal and external iliac arteries produced ischaemic lesions of the sciatic nerve and its branches, as well as direct muscle damage, in 5 out of 6 rabbits. In one animal, ligation of the aorta and of the internal iliac artery on one side produced a similar mixture of nerve and muscle damage on the side of the double ligation. Ligation of the femoral artery alone in 3 animals failed to produce significant changes. In the 6 affected animals there was paralysis of the hind leg on the side of the iliac ligations, with loss of tendon reflexes. Appreciation of pinprick over the foot and lower leg also appeared to be impaired. Complete ischaemic necrosis with irreversible damage to both neural and connective tissue elements did not occur in the main nerve trunks, but was present in some of the intramuscular nerve bundles as part of generalized coagulative necrosis of the most severely affected muscles. The characteristic pathological changes in the nerve fibres of the main nerve trunks were Wallerin degeneration and paranodal demyelination, the former being more extensive than the latter. In the animals with double iliac ligations, the upper level of ischaemic nerve damage was in the thigh, the tibial portion of the sciatic nerve being more commonly affected than the peroneal. Nerve and muscle damage tended to occur at different levels in the limb, but there was no example of clinical paresis due to neural damage without any ischaemic muscle changes being present. In two of the 3 animals in which the plantar muscles were examined, these muscles appeared to escape direct damage in spite of ischaemic lesions in the more proximal parts of the limb.