Influence of the facial nerve on facial bone growth and development in patients with congenital or acquired facial paralysis during childhood: A tomographic study.

Facial growth results from a complex combination of genetic and acquired factors. A number of studies indicate that the quality of mechanical stimuli generated during functional activities could significantly influence craniofacial morphology. We aimed to investigate whether congenital or acquired facial paralysis affects facial growth, given that muscular function may be impaired in patients with facial movement loss. To this end, facial computed tomography (CT) scans of 17 patients diagnosed with congenital or acquired facial paralysis during childhood from the Facial Nerve outpatient clinic at the Federal University of São Paulo were evaluated. Measurements on both paralyzed and unaffected sides were carefully performed to facilitate comparison. Through this comprehensive analysis, we observed that all the samples presented deviation toward the paralyzed side. In addition to that, when comparing the measurements between the two sides, eight variables showed statistical significance (p<0.05), including one that was related to the midface: the distance from the jugal point to the Frankfurt plane (p=0.003). The remaining seven were mandibular measurements: gonial angle (p=0.017), mandibular ramus length (p=0.019), distance from the mental foramen to Camper's plane (p<0.001), distance from the mental foramen to midsagittal plane (p=0.028), distance from the gonion to Camper's plane (p=0.025), condylar axis (p=0.002), and the position of the gonion in relation to the midsagittal plane (p=0.006). Thus, our findings strongly suggest that periosteal matrices under altered muscular stimuli due to paralysis may be associated with alterations in the facial skeletal framework.