Prospective Study of Facial Nerve Function After Surgical Procedures for the Treatment of Temporomandibular Pathology

Abstract

The aim of this prospective study was to report facial nerve injury following surgical procedures for the treatment of temporomandibular pathology, using the House-Brackmann facial nerve grading system (HBFNGS) as a means of classifying and measuring the degree and type of injury. The sample consisted of 32 patients who underwent temporomandibular joint (TMJ) surgery. A total of 50 approaches were carried out. Surgical procedures consisted of TMJ reconstruction, gap arthroplasty, eminectomy, bone plates for the treatment of chronic mandibular luxation, and disc plication. Facial nerve function of all patients was evaluated preoperatively and 24 hours after surgery. Patients who presented postoperative facial nerve injury were likewise examined using the HBFNGS at 24 hours, 1 week, 1 month, and 3 months. Of the 32 patients, 12.5% (ie, 8% of the 50 approaches) showed signs of facial nerve injury after TMJ surgery. The prevalence of postoperative facial nerve injury was significantly greater in the patients who had ankylosis (P = .014) and in those submitted to gap arthroplasty (P = .011). At 24 hours, none of the patients showed total nerve paralysis or severe dysfunction, only a moderately severe dysfunction (50%), or moderate dysfunction (50%). The forehead was the most affected area measured. At 3 months, all patients had recovered their normal facial nerve function. The overall improvement in facial nerve function was 40% for the patients classified initially with moderately severe dysfunction and 60% for those with moderate dysfunction. The frequency of facial nerve injury was related to the diagnosis of the temporomandibular pathology and surgical procedures. Facial nerve impairment was shown to be of a temporary nature. Moreover, there is a need to standardize the reporting of facial nerve recovery.