Does supercharging with cross-face nerve graft enhance smile in non-flaccid facial paralysis patients undergoing selective neurectomy?

Background: Cross face nerve grafting (CFNG) is a well-established nerve transfer technique in facial reanimation; however, no study has assessed outcome of supercharging the smile with CFNG in patients with synkinesis. The goal of this study was to examine the smile outcome in non-flaccid facial paralysis (NFFP) patients after supercharging with CFNG during selective neurectomy.Methods: NFFP patients who underwent CFNG with end-to-side coaptation to a smile branch on the paralyzed side during selective neurectomy were retrospectively identified and their charts were reviewed. Pre-operative and post-operative facial function was assessed with the electronic clinician-graded facial function tool (eFACE), and an automated computer-aided facial assessment tool (Emotrics). Smile metrics were compared pre-operatively, in early post-operative time (EPO, <6 months), and late post-operative time (LPO, >9 months) when CFNG contribution would be expected.Results: Thirteen cases were performed between June 2019 and December 2021. No objective smile metrics improved following supercharging with CFNG. Oral commissure excursion improved by 1.23 points in eFACE (p = .812), and by 0.84 in Emotrtics (p = .187) from EPO to LPO. EFACE dynamic score was improved by 0.08 points from EPO to LPO (p = .969).Conclusions: Using CFNG for supercharging the smile during selective neurectomy in NFFP patients may not enhance smile. Longer term results following supercharging and long term natural history of selective neurectomy should be assessed.