Three-Dimensional Composite Heatmaps of Unilateral Lambdoid Synostosis and Deformational Plagiocephaly

Background: The differentiation of unilateral lambdoid synostosis (ULS) and deformational plagiocephaly (DP) is vital to provide appropriate treatment intervention. Three-dimensional (3D) photo grammetry provides rapid, reproducible image capture without radiation exposure. Advanced analytical methods can help identify distinctive features to differentiate the two craniofacial conditions. This study uses 3D photogrammetry of ULS and DP patients to analyze the global cranial morphology for diagnostic differentiation. Methods: A retrospective review of 3D photogrammetry of 19 ULS and 25 DP patients were analyzed. Cranial vault asymmetry index, oblique cranial length ratio, and diagonal difference were measured. 3D photogrammetry-based composites were created and overlaid on age and gender-matched controls to generate heat maps representing morphologic differences in contour. Results: Cranial vault asymmetry index and oblique cranial length ratio were significantly different between ULS and DP (0.019; 0.022). 3D photogrammetry ULS composite showed retrusion in the ipsilateral occipitoparietal area, contralateral posterior parietal projection, contralateral frontal projection, relative ipsilateral mastoid bulge, and facial projection. DP composite showed unilateral occipital projection and contralateral anterior projection. The contralateral occipital regions in the occipital and anterior areas remained equivocal to control patients. Conclusions: Diagnostic differentiation of ULS and DP has previously relied on observation and linear measurements of cranial asymmetry in a single plane. 3D photogrammetry composites provide a global contour evaluation for diagnosis and longitudinal outcome analysis.