]Effect of epineurial neurorrhaphy on restoration of facial nerve injuries with different levels of neurotmesis in a rat model-a pilot study.

]Effect of epineurial neurorrhaphy on restoration of facial nerve injuries with different levels of neurotmesis in a rat model-a pilot study.

World Neurosurg. 2017 Dec 15;:

Authors: Shi S, Han Y, Xu L, Li J, Han Y, Cai J, Wang H

Abstract
BACKGROUND: Different degrees of neurotmesis of peripheral facial nerve were frequently encountered in clinic, for which the epineurial neurorrhaphy is a preference selection. However, considering the capability of self-restoration of nerves and side-effects of surgery, neurorrhaphy may not be optimal choice for various degrees of neurotmesis. This study was designed to explore the necessity of epineurial neurorrhaphy for different degrees of neurotmesis, as well to investigate the impact factors on neural functional recovery.
METHODS: The rat models were divided into the following 6 groups: Intact, noninjured controls; A, 1/3 cross-sectional facial nerve disconnected injury following epineurial neurorrhaphy; B, 1/3 cross-sectional facial nerve disconnected injury without epineurial neurorrhaphy; C. 2/3 cross-sectional facial nerve disconnected injury following epineurial neurorrhaphy; D, 2/3 cross-sectional facial nerve disconnected injury without epineurial neurorrhaphy; E, 2/3 cross-sectional facial nerve disconnection followed by complete transection and neurorrhaphy. The facial functional recovery was assessed by behavioral assessments and electrophysiological tests. The morphological changes of trunk of facial nerve (TF) were analyzed by osmium-toluidine blue staining and immunofluorescence. The modification of central nervous system was evaluated by retrograde labeling and Nissl's staining of facial nerve nuclei.
RESULTS: As for the morphological and functional assessment, there were no statistically significant differences among 1/3 facial nerve disconnected injury with or without epineurial neurorrhaphy and the intact model. For 2/3 facial nerve disconnected injury, direct neurorrhaphy was superior to complete transection followed by neurorrhaphy. For 2/3 facial nerve disconnected injury, though without epineurial neurorrhaphy, it can self-restore largely in neural structure and function. For the facial nerve nuclei, the number of neurons decreased in over 2/3 nerve disconnected models, model with 2/3 disconnection and without neurorrhaphy had the least number of neurons. For the distribution of neurons in different facial nerve sub-nuclei, both model with 2/3 nerve disconnection without neurorrhaphy, and model with 2/3 nerve disconnection following complete transection and neurorrhaphy demonstrated disorganization of neurons, in which the latter was more serious.
CONCLUSIONS: For 1/3 disconnected facial nerve injury, there's no need to suture the nerve stump. While for residual 1/3 connected nerve injury, direct suture is preferable if permitted than pre-performing complete transection to trim the stump, and residual 1/3 connected nerve fibers can self-restore largely. The neural functional defect may be attributed to the damage and misdirection of peripheral nerve fibers and central neurons.

PMID: 29253695 [PubMed - as supplied by publisher]

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