OF USING FIXATION SCREWS WIRES AS ALTERNATIVE LANDMARKS FOR CEPHALOMETRIC EVALUATION AFTER LEFORT-I OSTEOTOMY/

The most widely used method to measure postoperative stability of a su rgically repositioned bony segment is based on skeletal landmarks, Unf ortunately, orthognathic surgery may alter the skeletal landmarks and bony configurations that are commonly used for cephalometric analysis. Intraosseous wires, plates, and screws are routinely used in orthogna thic surgery, and postoperatively they are easier to identify than ske letal landmarks, Cephalometric radiographs from 25 adult patients, who had undergone LeFort I one piece osteotomy, were used to analyze the validity of fixation wires/screws used as landmarks to evaluate postop erative stability of the maxilla. The positional changes of maxillary skeletal landmarks (A point and anterior and posterior nasal spines) a nd intraosseous fixation wires/screws were measured relative to the cr anial base, The fixation screws/wires were also measured relative to t he invariant maxillary trabecular patterns and palatal plane from 1 to 6 weeks (T1-T2) and 6 weeks to 1 year postoperatively. The reproducib ility of fixation wires/screws was found to be higher than that of ske letal landmarks, The fixation wires/screws remained stable in the maxi lla; their postoperative positional changes were not significantly dif ferent from those of the skeletal landmarks. When the skeletal landmar ks are altered or no longer exist after LeFort I osteotomy, fixation w ires/screws could be used as alternative landmarks to measure the maxi llary postoperative stability.