Craniometric and Volumetric Analyses of Cranial Base and Cranial Vault Differences in Patients With Nonsyndromic Single-Suture Sagittal Craniosynostosis

Abstract

Purpose: How different from “normal” are the cranial base and vault of infants with nonsyndromic, single-suture sagittal synostosis (NSSS)? This study quantitatively addresses this question utilizing computed tomography (CT) analytic technology. Method: Head CT scans of infants with NSSS and normocephalic controls were analyzed using Mimics to calculate craniometric angles, distances, and segmented volumes. Craniometric measurements and asymmetry indices were compared between NSSS and control groups using linear regressions controlling for age. Ratios of anterior-, middle-, and posterior-to-total cranial vault volume were compared between groups using beta regressions controlling for age. Results: Seventeen patients with NSSS and 19 controls were identified. Cranial index and interoccipital angle were significantly smaller in NSSS compared with controls (P = 0.003 and <0.001, respectively). Right—but not left—external acoustic meatus angle and internal acoustic meatus-to-midline distance were significantly greater in NSSS than in controls (P = 0.021 and 0.016, respectively). NSSS patients and controls did not significantly differ in any asymmetry indices, except for the articular fossa angle asymmetry index (P = 0.016). Anterior vault volume proportion was greater in NSSS relative to controls (proportion ratio = 1.63, P < 0.001). NSSS trended toward a smaller posterior vault volume proportion (P = 0.068) yet did not differ in middle vault volume proportion compared with controls. Conclusion: In this small study, patients with nonsyndromic, single-suture sagittal craniosynostosis had relatively similar cranial base measurements, and larger anterior vault volumes, when compared with controls. Further work is needed to confirm the possibility of rightward asymmetry of the anterior cranial base.

A New Measure of Posterior Morphology in Sagittal Craniosynostosis: The Occipital Bullet Index

“…Vu et al hypothesized that the postero-inferior expansion observed in patients with SC is not su cient to compensate for transverse constriction. 10 As a result, posterior volumetric differences have been statistically insigni cant. [10][11][12] We therefore posit that volume-based measure may be insu cient for characterizing the atypia of the posterior cranium in this population.…”

“…10 As a result, posterior volumetric differences have been statistically insigni cant. [10][11][12] We therefore posit that volume-based measure may be insu cient for characterizing the atypia of the posterior cranium in this population.…”

“…6 Posterior cranial analysis has been largely limited to volumetric study. [10][11][12] While volume is a 3D measure, it lacks dimensional speci cation. For example, an increase in protrusion coupled with decrease in width yields minimal volumetric change.…”

“…[2][3][4][5][6][7] However, few attempts have been made to quantify the posterior prominence despite literature indicating the high frequency of individuals with sagittal craniosynostosis developing a posterior prominence. 8,9 Posterior cranial shape evaluation in patients with SC have been volumetric [10][11][12] or dependent upon computed tomographic (CT)based measures. 13,14 However, non-invasive surface laser-or 3D photographic modalities have been used to create 3D surface models without the use of radiation, 15 providing a safe option for tracking growth in a pediatric population allowing for serial preand post-operative evaluation.…”

Improved cephalic index following early cranial vault remodeling in patients with isolated nonsyndromic sagittal synostosis

“…However, recent studies have suggested the value of using 3D CT to assess patient head shape because it may more accurately reflect cosmetic outcomes. 30,31…”