Abstract: Abstract objectives: To study the possibility of Le FortⅠosteotomy correction for old maxillary fracture and to evaluate the clinical efficacy. Methods: Twenty-seven patients with old maxilla fracture were treated by Le Fort I osteotomy based on pre- and postoperative cephalometric and preoperative simulation and prediction （STO）analysis with RIF. Model surgery was performed on dental casts preoperatively. The pre-and postoperative measurements were compared with each other. Results: All cases healed well and had satisfactory occlusal function and facial form. The values of maxillary protrusion (SNA)，upper jaw protrusion distance (sn-g)and the cutting edge of central incisor to the palatal plane points (U1-pp) were decreased after operation than those of before operation (P<0.05)，but the value of N-ANS was increased(P<0.05). The values of G-Sn (//HP) and Ls-EP(⊥EP) were significantly decreased(P<0.05) after operation than those of before operation, but Cm-Sn-Ls and G-Sn(⊥HP) were increased compared with those of before operation (P<0.05). There was no recurrence after 3 - 6 months follow-up. Conclusion: Reconstruction of the maxillary with Le Fort I osteotomy is an effective method to treat delayed panfacial fractures.

Key words: old fracture, Le FortⅠOsteotomy, Rigid Internal Fixation, STO analysis