Differences between the anterior fontanelle surface area of term versus premature pediatric patients based on head CT

While studies have investigated normative ranges of anterior fontanelle (AF) closure and surface area (SA), they have focused on full-term children born without significant comorbidities that may impact the AF SA. Understanding the trends of AF SA and closure in patients with common pediatric conditions can help inform guidelines for screening the size of the AF and determining when to intervene. This study aimed to investigate the AF SA in pediatric patients between 0 and 24 months of age born either at term or prematurely.

A retrospective chart review investigated 346 pediatric patients between the ages of 0 and 24 months who underwent head CT imaging between January 2012 and December 2021. Patients with craniosynostosis and hydrocephalus were excluded. Mann-Whitney U-tests and Fisher's exact tests were used to compare the distribution of demographic variables between the term and premature patient cohorts. The length of the AF was measured in the coronal and sagittal planes to calculate SA. Mann-Whitney U-tests were used to compare median AF SA in the premature versus term cohorts of each age group.

A total of 346 patients were identified, with an average patient age of 156 days (5.2 months). Most patients were male (53.2%) and White (66.2%). Fifty-six patients (16.2%) in the study cohort were premature, and 290 (83.8%) were born at term. The most common indication for CT of the head/brain was trauma (51.2%). Overall, the median AF SA for children born at term increased until age 2 months, then decreased until closure, while the AF SA for premature children peaked at 5-6 months. The median AF SA was significantly larger in premature compared with term patients at 5-6 and 7-9 months (p < 0.05). With corrected ages for the premature cohort, there were no statistically significant differences in median AF SA between the patients born prematurely and at term.

This study provides insight into the hypothesis that AF SA varies, and specifically is larger, in premature children compared with children born at term. An enlarged AF in premature pediatric patients might signify normal development and may not necessitate neurosurgical referral.