Deformational brachycephaly: the clinical utility of the cranial index.

Objective: The incidence of deformational brachycephaly has risen since the "Back to Sleep" movement in 1992 by the American Academy of Pediatrics. Brachycephaly prevalence and understanding the dynamic nature of the pediatric skull have not been explored in relation to the cranial index (CI). The objective of the study was to determine the prevalence of brachycephaly, via the CI, with respect to time.

Methods: The authors conducted a retrospective review of 1499 patients ≤ 19 years of age who presented for trauma evaluation with a negative CT scan for trauma (absence of bleed) in 2018. The CI was calculated using CT at the lateral-most point of the parietal bone (cephalic width), and the distance from the glabella to the opisthocranion (cephalic length). Brachycephaly was defined as a CI ≥ 90%.

Results: The mean CI was 82.6, with an average patient age of 6.8 years. The prevalence of deformational brachycephaly steadily decreased from 27% to 4% from birth to > 2 years of life. The mean CI was statistically different between ages < 12 months, 12-24 months, and > 24 months (F[2,1496] = 124.058, p < 0.0005). A simple linear regression was calculated to predict the CI based on age; the CI was found to decrease by 0.038 each month. A significant regression equation was found (F[1,1497] = 296.846, p < 0.0005), with an R2 of 0.140.

Conclusions: The incidence of deformational brachycephaly is common in infants but decreases as the child progresses through early childhood. Clinicians can expect a significant decrease in mean CI at 12 and 24 months. Additionally, these regression models show that clinicians can expect continued improvement throughout childhood.