Electrophysiological assessment of a peptide amphiphile nanofiber nerve graft for facial nerve repair.

Facial nerve injury can cause severe long-term physical and psychological morbidity. There are limited repair options for an acutely transected facial nerve not amenable to primary neurorrhaphy. We hypothesize that a peptide amphiphile nanofiber neurograft may provide the nanostructure necessary to guide organized neural regeneration. Five experimental groups were compared, animals with (1) an intact nerve, (2) following resection of a nerve segment, and following resection and immediate repair with either a (3) autograft (using the resected nerve segment), (4) neurograft, or (5) empty conduit. The buccal branch of the rat facial nerve was directly stimulated with charge balanced biphasic electrical current pulses at different current amplitudes whereas nerve compound action potentials (nCAPs) and electromygraphic responses were recorded. After 8 weeks, the proximal buccal branch was surgically reexposed and electrically evoked nCAPs were recorded for groups 1-5. As expected, the intact nerves required significantly lower current amplitudes to evoke an nCAP than those repaired with the neurograft and autograft nerves. For other electrophysiologic parameters such as latency and maximum nCAP, there was no significant difference between the intact, autograft, and neurograft groups. The resected group had variable responses to electrical stimulation, and the empty tube group was electrically silent. Immunohistochemical analysis and transmission electron microscopy confirmed myelinated neural regeneration. This study demonstrates that the neuroregenerative capability of peptide amphiphile nanofiber neurografts is similar to the current clinical gold standard method of repair and holds potential as an off-the-shelf solution for facial reanimation and potentially peripheral nerve repair.

[Does transcranial magnetic stimulation provide improved assessment of "idiopathic" facial paralysis? Initial results]. / Lässt die transkranielle Magnetstimulation eine verbesserte Prognoseeinschätzung der "idiopathischen" Fazialisparese zu? Erste Ergebnisse.

To evaluate transcranial magnetic stimulation (TMS) in patients suffering from idiopathic facial palsy, results from 31 patients were reviewed. TMS was applied to the facial nerve by parieto-occipital, ipsilateral coil placement. At the time of the first examination (2-25 days after the onset of palsy), 11 of 31 nerves on the affected side were excitably by TMS. Patients were classified according to whether magnetic excitability of the facial nerve was possible (group I) or not possible (group II). In general, the percentage of patients with complete or nearly complete recovery of facial function was 97% following either a standard infusion therapy (corticosteroids, hydroxyethylstarch and pentoxifyllin) or orally administered corticoids (equal percentages in each group, respectively). In the first group of patients, 11 had facial nerves that were excitable with TMS and showed complete recovery of motor function within a median period of 7 weeks. In those patients with successful TMS only one experienced "crocodile tears" syndrome one year after Bell's palsy but without any further motor deficit of facial function. In patients with unresponsive nerve function following TMS 17 recovered without sequelae (median, 11 weeks), whereas 3 of 20 (15%) developed deficits of motor function. Two of these latter cases suffered from synkinesias (one that was slight after surgical decompression of the facial nerve and one severe) while one had facial contractures but without motor deficits.(ABSTRACT TRUNCATED AT 250 WORDS)