Selective marginal mandibular neurectomy for treatment of the marginal mandibular lip deformity in patients with chronic unilateral facial palsies.

Background: For unilateral facial palsies, reanimation techniques such as cross-facial nerve grafting with free muscle transfer have been very successful at improving symmetrical lip elevation when smiling. However, these procedures do not address the residual asymmetry with respect to lip depression resulting from an uncorrected marginal mandibular nerve palsy. Techniques that do address this residual lip asymmetry have had variable results. Selective neurectomy of the unaffected marginal mandibular nerve has largely been abandoned as a treatment since it has been reported to result in severe oral functional and cosmetic deficiencies. The authors argue that selective marginal mandibular neurectomy is a reliable technique for treatment of the marginal mandibular lip deformity that does not compromise oral functionality. Methods: Thirteen patients with unilateral facial palsies underwent selective marginal mandibular neurectomy of the unaffected side; the procedure was performed by the principal investigator. These patients were then evaluated on the basis of symmetry with smiling and oral functionality. Twelve of the patients were contacted and questioned with a standardized questionnaire. Twelve of the patients were evaluated independently for symmetry with smiling using randomized preoperative and postoperative photographs. Results: Eleven of the 12 patients reported either improvement or no change in oral competence. Ten of the 12 patients reported either improvement or great improvement in symmetry with smiling. Improvement in symmetry with smiling was independently observed 77.2 percent of the time. Conclusion: These results support selective marginal mandibular neurectomy of the unaffected side in patients with unilateral facial palsies as a means of improving symmetry with smiling without compromising functionality.