Impact of the Distance of Maxillary Advancement on Horizontal Relapse After Orthognathic Surgery.

BACKGROUND

The maxillary horizontal relapse following Le Fort I advancement has been estimated to be 10% to 50%. This retrospective review examines the direct association between the amounts of maxillary advancement and relapse. We hypothesize that the greater the advancement, the greater the relapse amount.

METHOD

Patients with class III skeletal malocclusion underwent maxillary advancement with either a Le Fort I or a Le Fort I with simultaneous mandibular setback (bimaxillary surgery) from 2008 to 2015. Patients were assessed for a history of cleft lip or cleft palate. Patients with known syndromes were excluded. Cephalometric analysis was performed to compare surgical and postsurgical changes.

RESULTS

Of 136 patients, 47.1% were males and 61.8% had a history of cleft. The mean surgery age was 18.9 (13.8-23) years and 53.7% underwent a bimaxillary procedure. A representative subgroup of 35 patients had preoperative, immediate postoperative, and an average of 1-year postoperative lateral cephalograms taken. The mean maxillary advancement was 6.3 mm and the horizontal relapse was 1.8 mm, indicating a 28.6% relapse. A history of cleft and amount of maxillary advancement were directly correlated, whereas bone grafting of the maxillary osteotomy sites was inversely correlated with the amount of relapse ( P < .05).

CONCLUSIONS

Our data suggest positive correlation between amount of maxillary advancement and horizontal relapse as well as a positive correlation between history of cleft and horizontal relapse. Bone grafting of the maxillary osteotomy sites has a protective effect on the relapse.