Craniofacial endotype of obstructive sleep apnea: Spatial matrix hypothesis.

This overview examines the craniofacial and myopathic endotypes of obstructive sleep apnea in relation to the spatial matrix hypothesis. Recently, attention has been drawn to the phenotype of obstructive sleep apnea since this condition includes neurologic, metabolic, craniofacial and myopathic endotypes. Most often, practitioners of dental sleep medicine focus their attention on the manipulation of the mandible for therapeutic purposes, but the etiology of the craniofacial endotype may reside elsewhere. Specifically, in line with the cranio-caudal gradient of development, consideration needs to be given to cranial base morphology during diagnostic assessment and treatment planning. In addition, the nasomaxillary complex needs to be examined since, empirically, the floor of the nose is the roof of the mouth and midfacial developmental compensation is not uncommon. Indeed, mandibular morphology needs to be evaluated since its clinical variation ranges from mandibular retrognathia to prognathism, and mandibular advancement may not be the treatment of choice in certain cases. Apart from skeletal considerations, soft tissue contributors to the upper airway, such as tongue position and pharyngeal muscle tone, need to be studied to hone case selection and targeted treatment planning. Therefore, the developmental dynamics of the upper airway are integrated, using the spatial matrix hypothesis, to help elucidate the patho-etiology in the clinical presentation of the craniofacial and myopathic endotypes of obstructive sleep apnea.