Facial nerve reconstruction using a split hypoglossal nerve with preservation of tongue function.

A prospective study conducted on 13 patients suffering from complete facial nerve injury (for 4 months up to 2 years) aimed to show that using the split hypoglossal nerve allows for reconstruction of the facial nerve with preservation of tongue function. The hypoglossal nerve was split longitudinally. For each half, a split of the hypoglossal nerve's response was measured intraoperatively by recording the compound muscle action potential of the tongue muscle. The half that showed the least response was selected for anastomosis. The facial nerve was transected at the stylomastoid foramen, and its distal part underwent a direct anastomosis with the selected half of the hypoglossal nerve. The six grades of the House-Brackman grading system were used to analyze the results. The average postoperative follow-up period was 3 years. Before surgery, 12 patients in this study were graded VI, with total paralysis, and 1 was graded V. After surgery, 2 of the 13 patients showed mild dysfunction (grade II), 7 patients showed moderate dysfunction (grade III), 3 patients showed moderately severe dysfunction (grade IV), and 1 patient showed a severe dysfunction (grade V). Microsurgical facial nerve reconstruction using a split hypoglossal nerve results in functional facial nerve improvement with preservation of tongue function.