Accuracy and Reliability of a System for the Digital Capture of Infant Head Shapes in the Treatment of Cranial Deformities

In Brief Deformational plagiocephaly (DP) is a multiplanar nonsynostotic cranial flattening that can occur either pre- or postnatally in infants secondary to prolonged application of external forces. Diagnosis and treatment of DP relies on accurate and consistent measurement and documentation of cranial anthropometrics. This investigation assessed the accuracy and reliability of measurement of the three-dimensional shape of a model of a plagiocephalic infant head using a noninvasive laser shape digitizer. Multiple scans were conducted by two certified and trained practitioners on two separate testing days in a repeated measures design. Digitized shapes were used to determine head diameters along diagonal lines ±30° from the anterior-posterior axis and circumference along a plane defined by landmarks on the sellion and the left and right tragion. These dimensions were also recorded with hand tools for comparison. No statistically significant differences occurred for any of the three dimensions when comparing results of digitally captured shapes between subjects and between testing sessions, indicating consistency of scanner use by different individuals and on different days. Differences versus results of hand tool measurement were larger than those noted between subjects or sessions for scanner data, on the order of 1 mm for linear measurements and 4 mm for circumference. These differences seemed to be caused by differences in hand tool measurement technique and software measurement algorithms. The results showed that the scanner investigated may be used consistently by different practitioners on different days, and that the consistency of the measuring sites selected by the scanner may suggest its favorability to hand tool measurement for common clinical use. Diagnosis and treatment of deformational plagiocephaly relies on accurate and consistent measurement and documentation of cranial anthropometrics. This investigation assesses the accuracy and reliability of measurement of the three-dimensional shape of a model of a plagiocephalic infant head using a non-invasive laser shape digitizer. Dimensions were also recorded with hand tools for comparison. The results showed that the scanner investigated may be used consistently by different practitioners on different days, and that the consistency of the measuring sites selected by the scanner may suggest its favorability to hand tool measurement for common clinical use.