The unseen third dimension: a novel approach for assessing head shape severity in infants with isolated sagittal synostosis.

Abstract

This study aimed to develop a novel approach to assess the severity of skull dysmorphology in infants with isolated sagittal synostosis (ISS) and its relationship with the surgical results. We divided 66 infants with ISS into three groups by combining the scaphocephalic (SSI-A) and platycephalic (VLI) indices as descriptors of the relation between length, width, and height. We evaluated each skull for morphology as hyperdolichocephalic (< 66%) versus dolichocephalic (66-77%) and as hyperplatycephalic (< 78%) versus platycephalic skull (78-85%). A score system was developed as follows: 2 points for values < 66% and < 78% and 1 point for values between 66 and 77% and 78 and 85% in SSI-A and VLI, respectively. The overall score was calculated and it was used to classify our patients on a 4-point ordinal scale, according to the severity of head shape (2 = mild, 3 = moderate, 4 = severe). Thirty-two infants resulted in mild group, 17 in moderate group, and 17 in severe group. SSI-A and VLI were reduced according to the severity of ISS. We demonstrated a positive correlation between SSA-A and VLI in mild subgroup of patients while we found a negative correlation between SSA-A and VLI in moderate and in severe subgroups. Moreover, a positive correlation was found between severe subgroup and Sloan III class of surgical results. This study describes a simple tool to better classify infants with ISS, considering the three-dimensional morphology of the skull, because it evaluates both the dolichocephalic and platycephalic component.