Changes of blood supply after intracanal decompression of the facial nerve

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There has been contravergy about the value of surgical decompression in cases of peripheral facial palsy. We have been engaged in researches on tasting and management 'of facial palsy. Outcomes of the surgical intervention with cases of severe facial palsy is not excellent as expected. Supported by the grant, we performed series of experimental and clinical studies. Our previous studies showed that interstitial fluid pressure of the facial nerve totally depended on CSF pressure, and that the interstitial pressure could be reduced by administration of mannitol.We extended the studies to improve treatments of facial palsy.We made an animal model of ischemic facial palsy by interrupting blood flow of the great petrosal aretery. Lesar doppler monitoring of blood flow of the facial nerve showed that decreased blood flow in ischemic facial palsy recovered after administration of mannitol. Histopathological studies of the ischemic facial nerve in guinea pigs showed that interstitial edema decreased after administration of mannitol. Mannitol prevented nerve degeneration of the nerve. Our clinical study also showed that mannitol was effective 'in early cases of Bell's palsy to prevent synkinesis after recovery of mimic movement.There are cases with Bell's palsy which need surgical decompression even with the use of mannitol decompression method.Conventional electrophysiological testings, such as ENOG, are not effective for selecting surgical cases. The site, degree, and recovering phase of the ischemic palsy could be monitored by antidromic facial nerve response in guinea pigs.The authors stress that accurate testing of the facial nerve lesion with antidromic response and early intracanal decompression of the nerve with mannitol is important to improve therapeutic results of facial palsy.