Abstract
The correlation between the neurophysiological values of facial nerve paralysis through electroneurography (ENoG) and the pathohistological findings of nerve damage was evaluated using a recently developed animal model for facial paralysis. Every week for four weeks after the onset of paralysis, the pathological levels of nerve damage in the buccal branch were compared with the ENoG values to evaluate the utility of ENoG. A histological study of the horizontal portion of the facial nerve as a primary ischemic lesion in an animal model was also performed. As a result, ENoG reflected the degree of the nerve damage in advance of the pathological changes during the initial week, and then accurately reflected the rate of nerve degeneration in the severe nerve damage two weeks after the onset. The main change one week after the onset of paralysis was edema among the nerve fibers. After the second week, a marked decrease in the number of nerve fibers was noted and macrophages started to absorb the products of degeneration. After the fourth week, and active regenerating process was observed. This study thus showed that a follow-up study using ENoG in patients with facial nerve paralysis can therefore provide valuable information that is both useful and relevant to their treatment.
