Experimentally induced facial nerve compression in cats.

An experimentally controlled compression of the facial nerve was induced in 32 cats by applying polyethylene tubes of different diameter on its main trunk. The effect of decompression (removal of the compressing tubes) was investigated by clinical evaluation of the eye blinking reflex, by recording the summation potential of the orbicularis oculi muscle and by histological investigation of the nerve specimens. The results obtained demonstrate that even in presence of degenerated nerve fibers, disrupture of the endoneural tubes can be avoided if decompression is performed within 12 days after injury. The release of circumferential pressure over the degenerated facial nerve within the above-mentioned delay is thus beneficial for optimal regeneration. The possible implications of these findings for the treatment of Bell's palsy are discussed.