Outcome measures of facial nerve regeneration: A review of murine model systems

Variability in the development of synkinesis in a rabbit facial nerve axotomy model

“…Rats are the most widely employed animal model for the study of synkinesis, with whisking and eye closure the most extensively utilized outcome measures. 10 Hadlock et al 11 developed a head fixation device in rats for the quantitative assessment of whisking amplitude, velocity, and acceleration. This also allowed a more accurate study of synkinesis 12 through the comparison of whisking and eye blink frequencies.…”

“…A large number of facial nerve studies subsequently utilized this model. 10 However, the discovery of cross-innervation by other facial nerve branches and innervation by autonomic neurons have reduced the validity of whisking as a direct indicator of facial nerve function. 10 A new model utilizing the interscutularis muscle 13 Figure 5 Composite score using the facial grading system and analysis using the GLLAMM model.…”

“…10 However, the discovery of cross-innervation by other facial nerve branches and innervation by autonomic neurons have reduced the validity of whisking as a direct indicator of facial nerve function. 10 A new model utilizing the interscutularis muscle 13 Figure 5 Composite score using the facial grading system and analysis using the GLLAMM model. The composite score differed according to the treatment groups with the highest score (best overall result) being Group 5 (immediate repair with contralateral temporary paralysis), and worst in the Group (delayed repair at 2 months).…”

“…Although rats, [6][7][8][9][10][11][12][13] mice, 14 , 15 and guinea pigs 16 are widely utilized in facial nerve research, we hypothesize that the larger size of rabbits [17][18][19][20][21] allows easier clinical evaluation of the face, particularly in the context of synkinesis. The rabbit also has constant anatomy with a large zygomatic branch innervating the orbicularis oculi and a large buccal branch innervating the quadratus labii inferioris.…”