Characterization of facial paresis in hemifacial microsomia

Objective. To provide an overview of the incidence, characteristics, and proposed etiologic mechanisms of facial paresis in patients with manifestations of hemifacial microsomia. Data Sources. PubMed database for English-language studies with no date restrictions. Review Methods. A comprehensive literature review was performed identifying all studies that discussed incidence, characterization, or etiologic mechanisms for facial paresis in hemifacial microsomia/oculo-auriculo-vertebral spectrum. Conclusions. This review supports that the prevalence of facial weakness in the spectrum of hemifacial microsomia/ oculo-auriculo-vertebral spectrum ranges from 10% to 45%. Most of these patients have involvement of all facial nerve branches or lower branches only. The most commonly involved single nerve branch has yet to be described. The 2 most common associated anomalies involve the mandible and auricle. Dysmorphogeneisis of the temporal bone and its effects on the facial nerve are most likely implicated in the cause of facial weakness. Implications for Practice. There is a wide variety of facial nerve presentations seen within oculo-auriculo-vertebral spectrum for which the exact etiologic mechanism is unclear. Through a better understanding of the presentation and etiology surrounding facial paresis in hemifacial microsomia, improved treatment options may be offered in the management of the facial weakness.