Swelling of the intratemporal facial nerve in Ramsay Hunt syndrome

Although Ramsay Hunt syndrome is one of the most important diseases causing peripheral facial palsy, the detailed pathology of the disease in the intratemporal facial nerve remains unclear. The purpose of this study was to increase knowledge of the pathogenesis of the syndrome by means of surgical findings. Between April 1976 and March 1997 we performed subtotal decompression of the facial nerve in 74 patients with severe Ramsay Hunt syndrome. The grade of nerve swelling was assessed using a microscope and recorded in a standardized form. The relationships between nerve swelling, the timing of surgery and the swelling of each segment were analyzed. Pronounced neural swelling, involving the geniculate ganglion and the horizontal segment, was consistent finding in the acute phase. Although the incidence of pronounced swelling of the horizontal segment gradually declined with time after onset, in most cases nerve swelling persisted even beyond the 16th week after onset. These data suggest that diffuse viral neuritis occurs throughout the intratemporal facial nerve. We assume that the viral inflammatory swelling involving the geniculate ganglion and horizontal segment is mostly responsible for the acute facial palsy in the acute phase.