Analysis of cranial type characteristics in term infants: a multi-center study

Background Positional head deformity (PHD) is defined as a change in the shape of an infant’s skull due to an external force. In certain cases, it can lead to cosmetic deformities or even neurological issues due to its impact on the developing nervous system. Therefore, we conducted this study to investigate the incidence and characteristics of PHD in term infants in China and preliminarily establish a localized diagnostic reference standard. Methods Overall, 4456 term infants from three medical institutions in Chongqing were and divided and analyzed according to their age. Cranial vault asymmetry (CVA) and cephalic index (CI) were calculated in all infants. The current international diagnostic criteria were used to understand PHD incidence and analyze the CVA and CI distribution. Results According to the current international standards, the total detection rate of PHD in Chongqing’s term infants was 81.5%, with brachycephaly alone being the most frequent (39.4%), followed by brachycephaly with plagiocephaly (34.8%) and plagiocephaly alone (6.2%). The detection rates of dolichocephaly were low: alone, 0.9% and combined with plagiocephaly, 0.2%. According to age, plagiocephaly (44.5%) and brachycephaly (82.0%) were the most frequent in the 2-3-month group. The 75th/90th/97th and 3rd/10th/25th/75th/90th/97th percentiles of CVA and CIs were 0.4/0.7/1.0 and 76.4/78.8/82.3/91.1/94.6/99.2%, respectively. Conclusions According to the current international standards, the PHD detection rate among term infants in Chongqing was high. Therefore, a new diagnostic standard for Chinese infants was proposed where CVA ≥ 0.4 cm indicates plagiocephaly, CI ≥ 91% indicates brachycephaly, and CI ≤ 82% indicates dolichocephaly.