Craniofacial Asymmetry in Adults With Neglected Congenital Muscular Torticollis

OBJECTIVE To evaluate the craniofacial asymmetry in adults with neglected congenital muscular torticollis (CMT) by quantitative assessment based on craniofacial three-dimensional computed tomography (3D-CT). METHODS Preoperative craniofacial asymmetry was measured by 3D-CT for 31 CMT subjects ≥18 years of age who visited a tertiary medical center and underwent 3D-CT between January 2009 and December 2013. The relationship between the age and the severity of craniofacial asymmetry was analyzed in reference to anteroposterior length asymmetry of the frontal bone and zygomatic arch, vertical and lateral displacements of the facial landmarks, and mandibular axis rotation. RESULTS The age at CT was 27.71±7.02 years (range, 18-44 years). All intra-class correlation coefficients were higher than 0.7, suggesting good inter-rater reliability (p<0.05) of all the measurements. The frontal and the zygomatic length ratio (i.e., the anteroposterior length asymmetry on the axial plane) was 1.06±0.03 and 1.07±0.03, respectively, which was increased significantly with age in the linear regression analysis (r(2)=0.176, p=0.019 and r(2)=0.188, p=0.015, respectively). The vertical or lateral displacement of the facial landmarks and rotation of the mandibular axis did not significantly correlate with age (p>0.05). CONCLUSION Craniofacial asymmetry of neglected CMT became more severe with age in terms of anteroposterior length asymmetry of the ipsilateral frontal bone and zygomatic arch on the axial plane even after growth cessation. This finding may enhance the understanding of therapeutic strategies for craniofacial asymmetry in adults with neglected CMT.