Purpose: This study focused on the correlation between the number of motor axons given to CFNGs for smile restoration, correlation with needle EMG's of the subsequently reinnervated mimetic muscle or transplanted free muscle, and aesthetic and functional outcomes as judged by a panel of independent reviewers.

Methods: 186 patients were included in this series, but only in 72 cases of CFNG procedures, adequate nerve biopsies were available. Patient information were collected from chart review from Stages I and II of facial reanimation procedures. Using Terzis' evaluation scale, functional and aesthetic outcomes for smile restoration as depicted in standardized videos were graded by four independent reviewers and data collected for each measurement. Histological slides included tissues, slides, or nerve biopsies embedded in plastic. Digital images of nerve specimens in stage I and II were processed using a high power microscope with a digital camera attachment. Using Meta Morph software, the numbers of motor axons were calculated except for the nerve specimens of the distal ends of nerve grafts in stage II that were quantitated manually by the investigator. All the data was analyzed buy SA 9.1.3 (Cary, NC) and the significance level was set as P<=0.05.

Results: The donor axonal input correlated with postoperative evaluation, and the number of distal end of nerve graft, but the latter didn't correlate with postoperative evaluation. CFNG procedure can help patient get better postoperative aesthetic recovery. Furthermore, 900 axons was found to be the cutoff point. If the count of donor nerve was above 900, having higher probability of good recovery would be possible.

Conclusion: The donor nerve influenced the final outcome more than the distal end of the cross-facial nerve graft. Though the counts of donor nerve correlated with the final outcome, some other factors, such as etiology of facial palsy, age of patient, denervation time, would influence the final results.