Evaluation of diagnostic sensitivity of electroneurography for facial neurotmesis

Abstract

OBJECTIVE: To evaluate diagnostic sensitivity of electroneurography (ENoG) for facial neurotmesis. METHODS: The data of 24 patients suffering from facial neurotmesis on one side, having non-emergency operation, and having preoperative records of ENoG were collected. Among the patients, 18 were men and 6 were women, aged from 3 to 55 years (median 28). The duration of injury before ENoG examination was from 1 to 56 days (mean 23.6 days) for them. The electroneurographic examination was carried out for facial nerves on both sides preoperatively. Percentages of evoked potential amplitude reduction on affected sides were calculated according to the value of normal side. The 90% reduction of amplitude was used as a cutting point. The facial neurotmesis was observed during operation. The sensitivity and false negative proportions of ENoG were analyzed. RESULTS: Among the 24 patients with facial neurotmesis, 22 had ENoG amplitude reduction over 90%, and 2 having this reduction less than 90%. The sensitivity and false negative proportions of ENoG in patients with facial neurotmesis were 91.7% and 8.3% respectively. CONCLUSION: The preoperative ENoG examination is high sensitivity for facial neurotmesis. The patients whose ENoG reduction over 90% should be advised to have a facial neurorrhaphy as soon as possible.