Using a 3D asymmetry index as a novel form for capturing complex three-dimensionality in positional plagiocephaly

Area of Science:

• Craniofacial development
• Pediatric orthopedics
• Medical imaging analysis

Background:

• Positional plagiocephaly (PP) is a common infant skull deformity.
• Current classification systems rely on limited 2D parameters, inadequately representing 3D head shape.
• This necessitates improved methods for accurate PP assessment and classification.

Purpose of the Study:

• To evaluate existing positional plagiocephaly (PP) measurement parameters.
• To validate a newly developed 3D parameter for quantifying PP.
• To introduce a novel 3D-based classification system for PP.

Main Methods:

• Validation of existing 2D and 3D parameters and a new 3D volume parameter using ROC curves.
• Utilized 3D stereophotogrammetry scans from 210 patients with PP and 50 controls.
• Assessed thresholds for the novel 3D asymmetry index parameter.

Main Results:

• The 3D asymmetry index demonstrates comparable quantification of PP to the 30° diagonal difference (gold standard).
• This 3D parameter enables a robust, 3D-based classification of positional plagiocephaly.
• The 3D asymmetry index is easily applicable and ensures intra- and inter-individual comparability.

Conclusions:

• The 3D asymmetry index provides a validated and accurate method for quantifying positional plagiocephaly.
• This new parameter facilitates a more precise, 3D-based classification of PP severity.
• The 3D asymmetry index enhances scientific analysis and clinical comparability in PP assessment.