Developmental unilateral facial palsy in a newborn: six cases and literature review.

Unilateral facial palsy in a newborn is rarely caused by a developmental defect. It occurs either isolated or in the context of a syndrome. This article describes a multidisciplinary approach towards unilateral, isolated congenital facial palsy along with a literature review. We report six patients, three boys and three girls, who presented with a unilateral facial palsy at birth. Clinical assessment was performed by an ear-nose-throat (ENT) surgeon, a pediatric neurologist, and an ophthalmologist. Magnetic resonance imaging (MRI) of the posterior fossa and computerized tomography (CT) of the temporal bone were requested to exclude structural anomalies of the facial nerve. Imaging revealed the underlying cause in five patients out of six (80%), showing an ipsilateral facial nerve aplasia or hypoplasia. These findings point towards an underlying developmental defect and underscore the importance of MRI in the diagnostic work-up. Surgical and non-surgical therapies were discussed with the parents.Conclusion: Congenital unilateral facial palsy caused by a developmental defect outside the context of a syndrome is rare. A multidisciplinary approach is recommended to differentiate between various causes and to initiate timely treatment.What is Known:• Congenital facial palsy is mostly caused by environmental/external fcators.• However in rare cases it can be developmental defect.What is New:• This paper describes 6 cases of isolated congenital facial palsy related to a developmental defect and presents the largest case series in the literature caused by aplasia/hypoplasia of the facial nerve.• MRI and CT-imaging allow for an assessment of the facial nerve at the root entry zone of the brainstem and along its course through the middle ear or the face. Moreover, they proved to be helpful in differentiating between several causes of congenital facial palsy.