Three‐dimensional cephalometry using individual skeletal laser technology models

Abstract

When planning operations on the facial skull, transversal asymmetries of the maxillo-mandibular complex cannot be adequately assessed using conventional two-dimensional (2D) x-ray cephalometry. On eight patients who presented with facial skull asymmetries, a three-dimensional (3D) laser technology model (LTM) using CT data was fabricated. Five sagittal plane points and six symmetry points were marked on the LTM, measured with the FlashPoint 3-D Digitizer and then geometrically converted, such that using the sagittal plane points, sella, basion, and nasion, a method could be developed that allowed the localization of each spatial point in the three symmetry planes. Thus one could quantitatively record a patient's specific facial skull asymmetry in all three planes and a 3D measurement became feasible. Based on the measurements, the asymmetry could be assessed with respect to the sagittal, vertical, and horizontal planes. With the 3-D LTM Digitizer measuring system, the surgeon now had precise numerical information regarding the symmetry ratios of the skull at his disposal, information that would have been difficult to evaluate solely using a model analysis. The results from this study show that our measuring system is applicable and useful for complex maxillofacial asymmetries. The planning of surgical interventions was optimized because precise numerical values regarding the degree of the asymmetry were available. With the 3-D LTM Digitizer measuring system, cephalometric analysis of complex asymmetries in the three spatial planes can be pragmatically supported.

Accuracy of using computer-aided rapid prototyping templates for mandible reconstruction with an iliac crest graft

“…Using the software we performed a virtual osteotomy of the affected mandible (Figure 2 ). Then a middle sagittal plane was determined by the sella, nasion, and subspinale points [ 3 ]. Upon this plane the image of unaffected side of mandible was reflected onto the resected side to restore the original mandibular contours (Figure 3 ).…”

Surgical Engineering in Cranio‐Maxillofacial Surgery: A Literature Review

“…CAS [45] was introduced in orthognathic surgery as one of the technologies (Table 2) to resolve multiple weaknesses and pitfalls of standard procedures (Table 1) [46]. The stages of the CAS workflow process for routine 3D virtual treatment planning of orthognathic surgery are the following: (1) image acquisition for 3D virtual orthognathic surgery, (2) processing of the acquired image data to construct a 3D virtual augmented model of the patient's head [47], (3) 3D virtual diagnosis of the patient [48], (4) 3D virtual treatment planning for the orthognathic surgery, (5) 3D virtual treatment planning communication, (6) 3D splint manufacturing, (7) 3D virtual treatment planning transfer to the OR, and (8) 3D virtual treatment outcome evaluation [49]. The image acquisition and processing of data for the 3D virtual treatment planning can merge information from bone (computed tomography (CT) scan, cone beam CT) [50,51], soft tissues [24,52], external facial appearance [53][54][55][56][57][58][59], 3D photographic system [57], and dental occlusion [47,[60][61][62][63] to provide the most complete 3D virtual model of each patient [64].…”