Long-term Stability Over 2 Years After Isolated Maxillary Orthognathic Surgery Combined With Mandibular Autorotation in Risk Patients for Condylar Resorption.

OBJECTIVE

Counterclockwise rotation of mandible can cause condylar resorption and condylar displacement posteroinferiorly after maxillary orthognathic surgery with mandibular in patients with high-angle mandibular retrognathism. This study was aimed to evaluate long-term stability >2 years and postoperative changes of condylar displacement.

MATERIALS AND METHODS

In 15 patients who underwent Le Fort I osteotomy with mandibular autorotation, postoperative stability was cephalometrically investigated until 2 years. Condylar changes were analyzed with transcranial temporomandibular joint projection. Correlation between condylar displacement and surgical movement was analyzed.

RESULTS

Significant clockwise relapse of mandible ( P <0.01 for SNB reduction and backward movement of point B) was observed between 6 months and >2 years after surgery, even though the values were small (0.5±0.1 degrees and 1.14±0.13 mm, respectively). The condyle was displaced posteroinferiorly immediately after surgery; however, it achieved a stable position at postoperative 6 weeks. The amount of vertical condylar displacement was significantly correlated with surgical change in mandibular posterior border sagittal angle, palatal plane angle, facial height ratio, and point B in the horizontal dimension. Greater mandibular rotation prompted more vertical condylar displacement.

CONCLUSIONS

Small mandibular relapse in long term should be considered after maxillary orthognathic surgery with mandibular autorotation, although it is regarded as a surgical maneuver to minimize mandibular instability in patients susceptible to postoperative condylar resorption.