Depressor Anguli Oris Function in Oral Macrostomia

Unilateral oral macrostomia can present in isolation or conjunction with other craniofacial abnormalities. Common associations include cartilaginous tags and accessory tragi, while the facial nerve is rarely involved. Our work is the first of its kind to report depressor anguli oris paralysis in the setting of oral macrostomia. The authors present 2 cases of unilateral oral macrostomia, with and without contralateral pre-operative depressor anguli oris paralysis, to highlight this often overlooked finding. Furthermore, these cases illustrate the impact of depressor anguli oris paralysis on postoperative outcomes and patient expectations. Depressor anguli oris function can be detected preoperatively and therefore should be weaved into surgical decision-making and used to manage expectations for symmetric facial animation following repair. Further work is required to evaluate the long-term benefits of electromyography and botulinum toxin injections as diagnostic and therapeutic modalities for DAO paralysis.