CROSS-FACIAL NERVE GRAFTING FOR FACIAL REANIMATION - EFFECT ON NORMALHEMIFACE MOTION

Reinnervation of the paralyzed hemiface with a cross-facial nerve graf t (CFNG) requires division of facial nerve branches on the normal hemi face to serve as axon donors. There is therefore concern about whether any impairment of normal hemiface motion occurs in the postoperative period. To minimize the likelihood of do nor-side impairment, donor br anches are chosen from the bucco-zygomatic region which has extensive cross branching, as opposed to the single temporal or marginal mandibu lar branches. This study chose to determine quantitatively if this pra ctice does, in fact, adversely affect the normal side hemiface motion governed by these branches, viz., eye closure, pucker, and smile. Sinc e surgical procedures near the facial nerve (such as superficial parot idectomy) may leave the patient with transient facial weakness, even i n the absence of nerve transection, the hypothesis was that hemiface m otion would be impaired on the donor side during the early postoperati ve period (first month) secondary to edema and/or neuropraxia. However , based on the clinical observation that donor-side facial motion is n ot demonstrably impaired late after surgery, a further hypothesis was that any early Facial motion impairment would return to normal by 3 mo nths postoperatively. Seven patients underwent sural CFNG as a primary or secondary component of their facial animation procedure. Their fac ial motion was quantified preoperatively and in serial postoperative e xaminations using the Maximal Static Response Assay (MSRA) of facial m otion. Careful selection of redundant bucco-zygomatic branches of the facial nerve on the normal side for CFNG did not ultimately (greater t han or equal to 3 months postoperative) impair the important motions o f eye closure, smile, or pucker. Early postoperative (less than or equ al to 1 month) weakness of the smile was seen on both X and Y axes, in dicating that both the risorius and zygomatic muscles were transiently weakened. The ability to elevate the lower eyelid was unaffected at a ny postoperative time point. Movement of the normal hemiface did not a ppear to be permanently affected by CFNG when a careful choice of redu ndant bucco-zygomatic donor branches was made.