Morphology of the Occipital Bones and Foramen Magnum Resulting From Premature Minor Suture Fusion in Crouzon Syndrome

Abstract

To identify skull-base growth patterns in Crouzon syndrome, we hypothesized premature minor suture fusion restricts occipital bone development, secondarily limiting foramen magnum expansion. Skull-base suture closure degree and cephalometric measurements were retrospectively studied using preoperative computed tomography (CT) scans and multiple linear regression analysis. Evaluation of multi-institutional CT images and 3D reconstructions from Wake Forest’s Craniofacial Imaging Database (WFCID). Sixty preoperative patients with Crouzon syndrome under 12 years-old were selected from WFCID. The control group included 60 age- and sex-matched patients without craniosynostosis or prior craniofacial surgery. None 2D and 3D cephalometric measurements. 3D volumetric evaluation of the basioccipital, exo-occipital, and supraoccipital bones revealed decreased growth in Crouzon syndrome, attributed solely to premature minor suture fusion. Spheno-occipital (β = −398.75; P < .05) and petrous-occipital (β = −727.5; P < .001) suture fusion reduced growth of the basioccipital bone; lambdoid suture (β = −14 723.1; P < .001) and occipitomastoid synchondrosis (β = −16 419.3; P < .001) fusion reduced growth of the supraoccipital bone; and petrous-occipital suture (β = −673.3; P < .001), anterior intraoccipital synchondrosis (β = −368.47; P < .05), and posterior intraoccipital synchondrosis (β = −6261.42; P < .01) fusion reduced growth of the exo-occipital bone. Foramen magnum morphology is restricted in Crouzon syndrome but not directly caused by early suture fusion. Premature minor suture fusion restricts the volume of developing occipital bones providing a plausible mechanism for observed foramen magnum anomalies.