The Effect of Baby-Sitter Procedure for Facial Nerve Paralysis in Rat.

【Purpose】In order to prevent atrophy of facial muscles, the “baby-sitter” procedure, which is a reconstruction technique for facial nerve complete paralysis, first the affected facial nerve to the same side hypoglossal nerve end to side neurorrhaphy or the like, the affected facial nerve to the nerve re-dominate the facial muscle, It is a method to change the movement source to the healthy facial nerve by using Cross-nerve graft in the beginning. Despite several reports of good clinical results of this procedure, histological and physiological demonstration using animal experiments has not been done yet. This study tried to establish a rat model of “baby-sitter” procedure for facial nerve complete paralysis.

【Method】The facial nerve trunk of 8-week-old Lewis rats was ligated and detached to prepare a facial nerve complete paralysis model. The affected side marginal mandibular branch was sutured end to side hypoglossal nerve. And Cross-nerve graft from healthy-side was transferred to affected side. 5 weeks later, Cross-nerve graft was sutured marginal mandibular branch end to end (Baby-sitter group). After 13 weeks from the first operation, physiological function evaluation was performed using retrograde tracer, induced electromyogram (CMAP), and mimic muscle and facial nerve branch were collected, and a histologic comparison study with intact group and non treatment group was conducted went.

【Result】 The staining of facial nucleus by retrograde tracer proved re-innervation of affected facial muscle by babysitter method. In CMAP, Babysitter group was also significantly higher than Amplitude, Duration, and Latency compared to non - treatment group. In the histological examination, the number of myelinated fibers, axon diameter and myelin sheath thickness were significantly higher in the Intact group than in the Baby-sitter group.

【Discussion】 In this study, the “baby-sitter” procedure for rat facial nerve palsy was established. Compared to the non-treated group histologically and physiologically, the Baby-sitter group could confirm the effect of shortening the denervation period using the affected hypoglossal nerve prevention effect of mimic muscle atrophy.