The Tinel Sign and Myelinated Axons in the Cross-Face Nerve Graft: Predictors of Smile Reanimation Outcome for Free Gracilis Muscle Transfer?

Introduction

During a two-stage free gracilis muscle transfer (FGMT) to restore smile to patients with facial paralysis, some surgeons assess nerve regeneration through the cross-face nerve graft (CFNG) with the Tinel sign and a nerve biopsy.

Objective

To test whether ultimate smile reanimation outcomes are correlated with (1) the Tinel sign or (2) myelinated axons of the biopsied CFNG at the time of FGMT.

Methods

Retrospective case series was performed at a tertiary care facial nerve center. Dynamic smile outcomes were quantified with Emotrics analysis of pre- and postoperative photographs.

Results

Of the 113 FGMT surgeries by CFNG performed since 2002, 92 patients had pre- and postoperative photo-documentation. Most patients (89%, N = 82) had a positive Tinel sign at the time of FGMT; however, 14 patients with positive Tinel signs were deemed failures. Interestingly, 4 patients with a negative Tinel sign went on to have successful dynamic outcomes and 16 patients lacking myelinated axons in their CFNG biopsy ultimately achieved successful smile outcomes.

Conclusion

Although the majority of patients had a positive Tinel sign and myelinated axons in the CFNG at the time of FGMT, the presence or absence of either factor did not predict ultimate smile outcome in this series.