Dynamic Reconstruction of Facial Paralysis in Craniofacial Microsomia

Background: Craniofacial microsomia is associated with maxillomandibular hypoplasia, microtia, soft-tissue deficiency, and variable severity of cranial nerve dysfunction, most often of the facial nerve. This study evaluated the incidence of facial paralysis in patients with craniofacial microsomia and outcomes after free functioning muscle transfer for dynamic smile reconstruction. Methods: A single-center, retrospective, cross-sectional study was performed from 1985 to 2018 to identify pediatric patients with craniofacial microsomia and severe facial nerve dysfunction who underwent dynamic smile reconstruction with free functioning muscle transfer. Preoperative and postoperative facial symmetry and oral commissure excursion during maximal smile were measured using photogrammetric facial analysis software. Results: This study included 186 patients with craniofacial microsomia; 41 patients (21 male patients, 20 female patients) had documented facial nerve dysfunction (22 percent) affecting all branches (51 percent) or the mandibular branch only (24 percent). Patients with severe facial paralysis (n = 8) underwent smile reconstruction with a free functioning muscle transfer neurotized either with a crossface nerve graft (n = 7) or with the ipsilateral motor nerve to masseter (n =1). All patients achieved volitional muscle contraction with improvement in lip symmetry and oral commissure excursion (median, 8 mm; interquartile range, 3 to 10 mm). The timing of orthognathic surgery and facial paralysis reconstruction was an important consideration in optimizing patient outcomes. Conclusions: The authors' institution's incidence of facial nerve dysfunction in children with craniofacial microsomia is 22 percent. Free functioning muscle transfer is a reliable option for smile reconstruction in children with craniofacial microsomia. To optimize outcomes, a novel treatment algorithm is proposed for craniofacial microsomia patients likely to require both orthognathic surgery and facial paralysis reconstruction.