“Craniometric and Volumetric Analyses of Normocephalic and Scaphocephalic Patients with Nonsyndromic Single-Suture Sagittal Craniosynostosis”

Purpose: Non-syndromic single-suture sagittal craniosynostosis presentation spans scaphocephalic and normocephalic head shapes. Herein, we studied craniometric differences between scaphocephalic and normocephalic patients with sagittal synostosis. Methods: Head CT scans of 20 scaphocephalic and 20 normocephalic sagittal synostosis patients and their age- and sex-matched controls were analyzed, including cranial base angles, distances-from-midline, and intracranial volumes. Results: Cranial index was significantly decreased in index groups compared to controls (p<0.001, respectively). Right external acoustic meatus angle (EAMA) was significantly larger in scaphocephalic (p<0.001) and left EAMA was significantly smaller in normocephalic patients (p=0.002) when compared with controls. Midline angular analysis showed that bifrontal angle was significantly smaller amongst scaphocephalic patients versus controls (p=0.026). Cranial base distances-from-midline were longer to the right and left internal acoustic meatus and shorter to the euryon-to-zygomaticofrontal suture for both groups of cases than their controls (p<0.05). Scaphocephalic patients had a larger anterior cranial volume ratio (18% vs 13%, p<0.001) and normocephalic patients had a larger posterior volume ratio (42% vs 33%, p<0.001) than controls. Scaphocephalic patients had larger anterior volume ratios than normocephalic patients (1.66 vs 1.16, p=0.025, but smaller posterior compartment volume ratios (0.90 vs 1.53, p<0.001). Conclusion: There are rightward asymmetries of the linear and angle cranial base measurements in both index groups. Intracranial volume distribution lies anteriorly in scaphocephalic patients but posteriorly in normocephalic patients. These data show craniometric evidence that although normocephalic and scaphocephalic patients share the diagnosis of “sagittal synostosis,” they are morphometrically different than each other and controls.