A correlation study of endoneurial fluid pressure and electroneurography of the facial nerve.
OBJECTIVE
The relationship between endoneurial fluid pressure (EFP) and electroneurography (ENoG) of the facial nerve was studied in order to evaluate the pathophysilogical basis of ENoG to serve as the criteria for decompression of the facial nerve.


METHODS
While the values of ENoG were recorded by an instrument for physiology on the normal and crushed facial nerves of guinea pigs, EFPs were measured at the same time by a servo-nulling micropipette system. After the elevated EFP was measured, the facial nerves were removed and then fixed properly for examination under the light and electron microscope in order to determine the differences from various periods after injury.


RESULTS
With the change of EFP in the facial nerve during the period from day 3 to the third week after crushed injury, the percentage of degenerated facial nerve fiber increased. There was a positive correlation between ENoG and EFP. The coefficient was 0.88 and 0.51 in the second and third week after crushed injury, respectively. Extensive edema in endoneurial and perivascular spaces of the facial nerve could be found at the early stage of injury, while proliferation of numerous Schwann cells appeared at the later stage.


CONCLUSIONS
The change of ENoG could reflect the value of EFP relatively within 3 weeks after crushed injury. Our data indicate that ENoG could be useful to evaluate the pathogenesis underlying facial palsy.
Chen
Bing
B
Department of Otology and Skull Base Surgery, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, People's Republic of China. chenbingear@hotmail.com
Yuan
Ya-Sheng
YS
Wang
De-Hui
DH
Chi
Fang-Lu
FL
Wang
Zheng-Min
ZM
D000818:Animals; D004487:Edema / Q000378:metabolism*; D004594:Electrophysiology; D005154:Facial Nerve / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D005158:Facial Paralysis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006168:Guinea Pigs; D008866:Microsurgery; D010525:Peripheral Nerves / Q000378:metabolism* / Q000601:surgery; D011312:Pressure