Changes in endoneurial fluid pressure in the crushed facial nerve]

OBJECTIVE: To investigate the changes in endoneurial fluid pressure (EFP) and diameter of the crushed facial nerves in guinea pigs in order to determine whether there is necessity and the opportunity of the facial nerves decompression in different stage after injury. METHODS: EFP were measured using a servo-nulling micropipette system in the normal and crushed facial nerves. RESULTS: The results showed that the EFP in the facial nerve increased significantly after compression. The highest pressure of EFP 12.94 +/- 1.69 mmHg occurred at the end of the first week after injury, which was 4 to 5 times as great as that of normal ones. This change lasted about two weeks, then it returned to normal at the third or the fourth week. The largest diameter of the facial nerve 1.01 +/- 0.08 mm was seen at the end of the first week after crush injury. CONCLUSION: It suggested that the servonulling micropiette system was useful in evaluating the pathogenesis of facial palsy. It could provide the laboratory basis for facial nerve decompression.