Differential Reanimation of the Upper and Lower Face Using 2 Interpositional Nerve Grafts in Total Facial Nerve Reconstruction

Radical parotidectomy often results in complex facial nerve defects involving the main nerve trunk and multiple distal nerve branches. Although cable nerve grafting often leads to good nerve regeneration, severe synkinesis due to aberrant axonal regrowth is inevitable. In such situations, the use of 2 motor sources to differentially reanimate the upper and lower face could minimize synkinesis. Here we describe a method of total facial nerve reconstruction in which the upper and lower face are differentially reconstructed with the hypoglossal nerve and facial nerve, respectively, using 2 interpositional nerve grafts. Reconstruction of the lower face with the facial nerve restored voluntary and coordinated animation, and reconstruction of the upper face with the hypoglossal nerve restored frontalis muscle tone and eye closure. These results suggest that our method could serve as an alternative to conventional techniques that use only the facial or hypoglossal nerve.