We introduced a surgical protocol to achieve accurate maxillary multidirectional movement in Le Fort I osteotomies. This comprised a way of controlling precision and a guiding device together with prebent titanium plates. We evaluated the protocol using a semiautomated 3-dimensional assessment in 22 patients with maxillary multidirectional movement (movement in three or more of six directions). Operations were all done between October 2015 and April 2017 by the same surgeon, who followed the protocol strictly. To evaluate the accuracy, we measured the deviation of the orientation of landmarks and of the upper dentition. All cases were followed up for at least a year. They all involved maxillary movement in at least three directions, and nine involved movement in six. The guiding device was used intraoperatively in all cases. Vertical deviation of the segments of bone was often detected during removal of bone, and sagittal deviation in three cases, but we found no transverse deviations. The assessment of accuracy showed that the mediolateral, anteroposterior, and superoinferior translations of landmarks were all less than 1mm, with mean values of 0.29, 0.43, and 0.39mm, respectively. The pitch, roll, and yaw of the upper dentition were also less than 1°, with mean values of 0.60°, 0.35°, 0.36°, respectively. The proposed protocol allowed accurate reposition of the maxilla with multidirectional movement during Le Fort I osteotomy.
Keywords: CAD/CAM; Le Fort I osteotomy; Orthognathic surgery; Titanium plate.
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