The use of local anesthetic motor block to demonstrate the potential outcome of depressor labii inferioris resection in patients with facial paralysis

Background: If a patient with unilateral facial paralysis has marked depressor activity on the normal side, the appearance of the lower lip when smiling is asymmetrical. Defunctioning the muscle on the contralateral side to the palsy can restore balance. This can be achieved by resccting a portion of the depressor labii inferioris muscle on the nonparalyzed side. However, the decision to resect normal muscle may be difficult for many patients. This article presents the role of a local anesthetic motor block in temporarily paralyzing the muscle before patients decide whether permanent resection will meet their needs. Method: A phone questionnaire with 15 patients who received motor muscle blockage before deciding to have depressor labii inferioris muscle resection was conducted. Results: Ninety-three percent of the patients who underwent the local anesthetic motor block stated that it gave them valuable information regarding the outcome of their surgery and influenced their decision to undertake definitive depressor muscle resection. Conclusion: A trial by local anesthetic before depressor inferioris muscle resection provides patients with valuable insight into the likely outcome of the surgery. Patients with unilateral facial paralysis have marked depressor activity on the normal side, causing an asymmetrical appearance of the lower lip when smiling. Defunctioning the muscle on the nonparalyzed side by resecting a portion of the depressor labii inferioris muscle can correct this asymmetry. However, the decision to resect normal muscle may be difficult for many patients. A local anesthetic motor block to temporarily paralyze the depressor labii inferioris muscle can help patients decide whether permanent muscle resection will meet their needs.