UCSQ Method Applied on 3D Photogrammetry: Non-Invasive Objective Differentiation Between Synostotic and Positional Plagiocephaly.

Objective: Objective differentiation between unilateral coronal synostosis (UCS) and positional posterior plagiocephaly (PPP) based on 3D photogrammetry according to Utrecht Cranial Shape Quantificator (UCSQ).
Design: Retrospective study.
Setting: Primary craniofacial center.
Patients, Participants: Thirty-two unoperated patients (17 UCS; 15 PPP) (age < 1 year).
Interventions: Extraction of variables from sinusoid curves derived using UCSQ: asymmetry ratio forehead and occiput peak, ratio of gradient forehead and occiput peak, location forehead and occiput peak.
Main Outcome Measure(s): Variables, derived using 3D photogrammetry, were analyzed for differentiation between UCS and PPP.
Results: Frontal peak was shifted to the right side of the head in left-sided UCS (mean x -value 207 [192-220]), and right-sided PPP (mean x -value 210 [200-216]), and to the left in right-sided UCS (mean x -value 161 [156-166]), and left-sided PPP (mean x -value 150 [144-154]). Occipital peak was significantly shifted to the right side of the head in left-sided PPP (mean x -value 338 [336-340]) and to the left in right-sided PPP (mean x -value 23 [14-32]). Mean x -value of occipital peak was 9 (354-30) in left- and 2 (350-12) in right-sided UCS. Calculated ratio of gradient of the frontal peak is, in combination with the calculated asymmetry ratio of the frontal peak, a distinctive finding.
Conclusions: UCSQ objectively captures shape of synostotic and positional plagiocephaly using 3D photogrammetry, we therefore developed a suitable method to objectively differentiate UCS from PPP using radiation-free methods.