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A review of the literature revealed 91 cases of massive osteolysis since the first report by Jackson in 1838, including 31 in the maxillofacial region meeting the Heffez criteria. In seven cases, early irradiation was performed, after which no further progression of bone lysis was observed. The young female patient reported here has been followed up clinically and radiologically for 7 years after radiotherapy, during which time she has remained stable, with no progression of the osteolysis. Our experience with this patient appears to confirm that early radiotherapy with a dose of 30-40 Gy prevents further progression of the disease and can even lead to recalcification. On this basis, and provided the patient remains symptom-free, reconstructive surgery appears a viable treatment option.

Oral and maxillofacial surgery has long needed a methodology for accurate definition of the third dimension. The introduction of computer-aided tomography in the 1970s provided surgeons with multiple 2-D maps which they themselves had to conceptualize into a third dimension. The later advent of computerized summation of these data made it possible to display a perspective view of the third dimension on a TV monitor. CT, and more recently MRI, with the further analytical refinement afforded by software processing (interactive data presentation, contour detection and summation, hypothetical 3-D construction and interactive visualization) now provide the basic information that is needed for the fabrication of an individual model. Such models can be milled from a variety of materials. More recently, laser-hardened acrylic resins have been shown to be a useful alternative. Both systems are described and their advantages and disadvantages in the planning and performance of oral and maxillofacial surgical procedures are discussed.

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.

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