SURGICAL INTERVENTION ON THE FACIAL-NERVE IN THE AGED PATIENT - MORPHOLOGICAL EVIDENCE FOR THE POOR FUNCTIONAL OUTCOME

Nerve sutures such as facial-facial anastomosis are helpful methods fo r recovery of facial movements after peripheral nerve lesions. Most of the results on neuronal regeneration were based on experiments with y oung or young adult animals. In contrary the vast majority of the dise ases (cholesteatoma or tumors of the parotid gland) causing facial ner ve lesions are in aged patients. Method: Therefore, we compared the or iginal data from two recently published articles concerning the axonal outgrowing process after facial-facial-anastomosis in young-adult and aged rats. In additional, we tried to explain the clinically observed postparalytic syndrome (synkinesia, autoparalytic syndrome,...) after surgical interventions on the facial nerve with the experimental resu lts in the rat. Results: As an important result, we could not find spo ntaneous loss of facial motoneurons on the control side in the aged ra ts. On the operated side, two results have to be emphasized. The initi al regeneration (10-42 days after the operation) showed a significant faster reinnervation in the group of young rats. The aged rats showed an apparent hyperinnervation after axonal outgrow to the mimic muscles has been accomplished. Conclusion: Both experimental observations are in agreement with our clinical experiences. After facial nerve surger y, aged patients show a delayed recovery of the mimic functions and a more pronounced postparalytic syndrom. A morphological explanation one can bear is that the delayed reinnervation causes the extreme hyerinn ervation, which leads to a simultaneous innervation of different muscl es by same facial motoneurons.