The validation of morphometric outcomes and stratification system for nonsyndromic sagittal craniosynostosis following total calvarial remodeling

Abstract

This study aimed to provide an external validation of morphometric outcomes, including recently developed parameters — vertico-longitudinal index (VLI) and vertex-nasion-opisthocranion (VNO) angle — along with a proposed stratification system for nonsyndromic sagittal craniosynostosis (NSC). Thin-cut CT scans performed before and after total calvarial remodeling in 70 NSC children (mean preoperative age, 7.0 months; mean postoperative age 23.8 months) were evaluated. The parameters, including linear dimensions, morphometry-based indices, and cranial angles, were measured at the cranial vault and base. Each patient was also assigned a scaphocephaly severity score (SSS). The obtained data were compared with an age-matched control group of 80 normocephalic children.

After surgery, all dimensions of the cranial vault increased, but did not normalize (p < 0.0001). Contrarily, some normalization was noted in the skull base, within the anterior and posterior cranial fossae. Postoperative results confirmed the diagnostic cut-off level for VNO at 50°; however, the proposed VLI cut-offs skewed the accuracy of SSS in the control group.

To the best of our knowledge, this study was the first to discuss the value of an NSC stratification system in relation to underlying components. The SSS has a relevant background, but its accuracy would increase with a redefinition of normative VLI ranges.