Abstract
Functional preservation of the marginal mandibular branch of the facial nerve is crucial in head and neck surgeries. It is important not only for the postoperative QOL of the operated patients, but also for improving the surgical skills of the surgeons. Appropriate evaluation of postoperative facial paralysis is necessary for utilizing feedback information. In this study, we retrospectively analyzed the postoperative status of marginal mandibular branch function.
Patients with non-malignant disease who underwent parotidectomy were selected. One hundred consecutive patients who were operated from 2013 were included. None had preoperative facial paralysis. Mean and standard deviation of age were 54.8 and 16.4. Fifty males and 50 females were included. Postoperative mobility of the lip was evaluated in depressing and everting the lip. In addition, the function of the mentalis muscle was scored by inspection and palpation; no paralysis as score 0, complete paralysis as score 2, and incomplete paralysis as score 1. This was assessed at day 2, 1 month, 2 months and 3 months after surgery.
Asymmetric depressing of the lip occurred in 36 of the 100 patients. In these, the number of patients with each score (0 to 2) of the mentalis muscle paralysis was 22, 9, and 5, respectively. Residual rates of asymmetric depressing in patients with score 0 were 31.8% in 1 month, 22.7% in 2 months, 4.5% in 3 months after surgery. Those incidences were 77.7%, 55.5%, 55.5% in patients with score 1. There were no patients with score 2 whose asymmetric depressing of the lip was cured within 3 months after surgery.
Prognosis of asymmetrical depressing of the lip could be predicted by assessing contraction of the mentalis muscle in protrusion of the lip after surgery, which might indicate the postoperative condition of the marginal mandibular branch of the facial nerve.
