The digital model process illustrated in Figure 1 A began with a preoperation spiral CT scan (Siemens Somatom Definition Flash). DICOM (Digital Imaging and Communications in Medicine) images from the scanner were imported into Mimics (Research v 21.0, Materialise, Leuven, Belgium) for segmentation of the skull. A mask created using the “Bone CT” threshold (226-3071 HU) was used to isolate the bone material from the surrounding soft tissue based on variations in Hounsfield units. The mask was manually edited to remove artifacts. A 3D object of the bone mask was generated and exported as a standard tessellation (STL) file. This STL file was imported into Geomagic (2014, 3D Systems, Rock Hill, S.C.), in which a smoothing operation was performed. A coordinate system was manually established and defined using the X-Y-Z axes as shown in Figure 1 B. This also established the medial, sagittal, and coronal planes. The anterior (A)-posterior (P) axis was defined as the x-axis, the superior (S)-inferior (I) axis was defined as the y-axis, and the lateral (L)-medial (M) axis was defined as the z-axis.
The intact nontrauma side was isolated and a mirror function across the mid-sagittal plane was performed. The skull model was further isolated approximately 30 mm superiorly of the orbit, inferiorly to include a portion of the upper dentition, and posteriorly to include the full zygomatic arch.
The intact nontrauma side was isolated and a mirror function across the mid-sagittal plane was performed. The skull model was further isolated approximately 30 mm superiorly of the orbit, inferiorly to include a portion of the upper dentition, and posteriorly to include the full zygomatic arch.