Outcome of different facial nerve reconstruction techniques

Abstract Introduction: There is no technique of facial nerve reconstruction that guarantees facial function recovery up to grade III. Objective: To evaluate the efficacy and safety of different facial nerve reconstruction techniques. Methods: Facial nerve reconstruction was performed in 22 patients (facial nerve interpositional graft in 11 patients and hypoglossal-facial nerve transfer in another 11 patients). All patients had facial function House-Brackmann (HB) grade VI, either caused by trauma or after resection of a tumor. All patients were submitted to a primary nerve reconstruction except 7 patients, where late reconstruction was performed two weeks to four months after the initial surgery. The follow-up period was at least two years. Results: For facial nerve interpositional graft technique, we achieved facial function HB grade III in eight patients and grade IV in three patients. Synkinesis was found in eight patients, and facial contracture with synkinesis was found in two patients. In regards to hypoglossal-facial nerve transfer using different modifications, we achieved facial function HB grade III in nine patients and grade IV in two patients. Facial contracture, synkinesis and tongue atrophy were found in three patients, and synkinesis was found in five patients. However, those who had primary direct facial-hypoglossal end-to-side anastomosis showed the best result without any neurological deficit. Conclusion: Among various reanimation techniques, when indicated, direct end-to-side facial-hypoglossal anastomosis through epineural suturing is the most effective technique with excellent outcomes for facial reanimation and preservation of tongue movement, particularly when performed as a primary technique

AGE- RELATED CHANGES IN ELECTROPHYSIOLOGICAL PROPERTIES CBA/N MICE UTRICULAR TYPE II HAIR CELLS

Objective This study investigated vestibular functional declination with age, leading to age-related deterioration of balance function. It has been shown that the impaired vestibular function is derived from structural and/or functional degeneration of vestibular hair cells. Methods We quantitatively analyzed the number of hair cells in the utricle of CBA/N mice at 2 different ages (5 weeks old and 26 weeks old) using immunohistochemistry. In addition, electrophysiological properties of type II hair cells were evaluated by the patch clamp method. Results We found a significant difference in the number of hair cells between the two groups, i.e., the number of hair cells was significantly less in the adult group than in the young group. Electrophysiological experiments revealed that the current density of the delayed rectifier K^+ current was significantly lower in adult mice than in young mice, with little change in activation kinetics. Conclusions These findings suggest that not only hair cell loss but also alterations in hair cell functions, resulting from aging, is involved in balance dysfunction