Combining an end to side nerve to masseter transfer with cross face nerve graft for functional upgrade in partial facial paralysis–an observational cohort study

Abstract

Results of a single stage technique combining cross facial nerve graft(s) (CFNG) with an ipsilateral end to side nerve to masseter transfer (NTM) in incomplete facial paralysis are assessed in a retrospective cohort study. The hypothesis is that the technique can safely improve the quality of smile in these patients. End to side coaptations for the recipient facial nerve minimise the risk of iatrogenic function loss, contrasting with the end to end neurorrhaphies used in conventional babysitting procedures. A series of 27 patients was studied through case note review and standardised assessments. Surgical technique involves extensive exposure of the facial nerve and the NTM on the affected side and access is by bilateral preauricular incisions. End to end coaptations are made to the facial nerve on the donor side and on the recipient a standard CFNG is combined with an end to side NTM coaptation. Follow up was a minimum of 9 months from surgery. Overall improvement in the Sunnybrook scale averaged 33, from a pre-operative score of 40 (p < 0.05). Average upgrade of 4.7 mm of increased movement at the modiolus was achieved (p < 0.05), 43% improvement compared to the normal side. An improved resting symmetry of 3.8 mm was achieved in relevant cases. Where eye closure was strengthened the average improvement was 5 mm of increased lid closure. The smile achieved was spontaneous in 22 of 27 cases. The study confirms the hypothesis that CFNG with NTM transfer offers a physiological upgrade of facial movement in partial facial paralysis, applicable in both early and longstanding cases.