Comparison of different midsagittal plane configurations for evaluating craniofacial asymmetry by expert preference

Introduction In this study, we aimed to compare 8 candidate midsagittal planes (MSPs) constructed from different median landmarks to determine the most appropriate one for evaluating craniofacial asymmetry. Methods We included 30 patients (18 men, 12 women; mean age, 25.7 ± 6.03 years) who visited the National Health Insurance Service Ilsan Hospital in Gyeonggi-do, Korea, with a complaint of facial asymmetry. Four MSPs passing through 2 median landmarks perpendicular to the Frankfort horizontal plane and 4 other MSPs passing through 3 median landmarks were constructed. Menton, anterior nasal spine, and anterior nasal spine-to-posterior nasal spine line deviations were evaluated using these 8 MSPs. Eight MSPs from 30 subjects were shown to 6 experts, who selected the planes that they considered the most appropriate. Results Experts most frequently selected the plane passing through nasion and basion perpendicular to the Frankfort horizontal plane (66 of 180 times; P <0.05). In evaluating craniofacial asymmetry, using MSPs passing through 3 median landmarks in the cranial base can lead to underestimation of the asymmetry of the menton, anterior nasal spine, and anterior nasal spine-to-posterior nasal spine line. Conclusions We suggest using MSPs perpendicular to the Frankfort horizontal plane or a plane passing through anterior nasal spine in clinical practice.