A Physician-Centered Craniofacial Asymmetry Index for the Severity of Plagiocephaly: A Comparative Study of Assessment Methods

Background Plagiocephaly, wherein infants' head exhibits a diagonal asymmetry, is currently diagnosed based on physicians' subjective judgment. Discrepancies between physician and parent perspectives may result in dissatisfaction with treatment outcomes. This problem highlights the need for an objective assessment system aligning with physician-made clinical diagnoses. Methods Infant heads were modeled using 3-dimensional scanning techniques. We developed a craniofacial asymmetric index (CAI) based on 10 height planes of heads with varying weight. CAI and traditional craniofacial vault asymmetry index (CVAI) of 10 infants undergoing helmet therapy were compared with 11 craniofacial surgeons' judgment. The Pearson correlation coefficient and Bland-Altman plot were used to determine the correlations and agreement between physicians' judgment and the aforementioned assessment methods. The adjusted intraclass correlation coefficient was calculated to evaluate the reliability of between-physician agreement. Results All 10 infants were divided into the following 3 severity groups: severe, moderate, and mild groups based on craniofacial surgeons' judgment. Notably in CAI, front/back halves of skull and multiangular weighting factors were evaluated. The evaluation revealed perfect alignment in severity classification between the CAI and physicians' judgment, whereas both the CVAI score and MATLAB analysis show varying degrees of difference, 6 and 4 distinct results, respectively. Coefficients of the correlations of physician-assigned scores with the MATLAB analysis, CVAI score, and CAI score were 0.500, 0.833, and 1.000, respectively. Furthermore, Bland-Altman plots revealed the best agreement between CAI and physician-assigned scores. Conclusions CAI closely aligns with the subjective judgment of craniofacial surgeons' assessing the severity of plagiocephaly in infants.