Objective: To describe a case of mandibular distraction osteogenesis (DO) combined with sliding genioplasty, using skeletal anchorage, for treating micrognathia with temporomandibular joint (TMJ) ankylosis and obstructive sleep apnea in a 16-year-old female patient.
Cases: The patient presented with severely restricted mouth opening, difficulty in chewing, snoring. Her facial profile was convex with severe micrognathia. Cephalometric analysis indicated a severe skeletal Class II malocclusion with high mandibular plane angle. Computed tomography images showed hypoplasia and ankylosis on both sides of the condyle. The patient underwent standard polysomnography, which revealed a high apnea-hypopnea index (AHI), frequent arousals, and depression of lowest oxygen saturation (SaO₂) during sleep. The authors first performed mobilization of the TMJ, increasing the maximum mouth opening from 5.0 mm to 32.0 mm. Subsequently, orthodontic treatment and advancement of the mandible were carried out by mandibular DO, using miniscrews and miniplates. Finally, sliding genioplasty was performed to bring the tip of the mandible forward. An improved facial appearance and good occlusion were eventually achieved, and AHI decreased from 37.1 to 8.7. The change of the pogonion in the anteroposterior direction and the amount of downward rotation of the mandible during advancement at 24 months post-treatment were negligible.
Discussion and Summary: Using skeletal anchorage with intermaxillary elastics after mandibular DO is useful for preventing extrusion of the upper and lower anterior teeth, thereby preventing rotation of the mandible. In addition, mandibular DO combined with sliding genioplasty is effective in improving both dentofacial deformities and impaired respiratory function.