ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of distraction osteogenesis (DO) in the treatment of severe mandibular micrognathia with severe obstructive sleep apnea and hypopnea syndrome (OSAHS).</p><p><b>METHODS</b>19 cases of severe mandibular micrognathia with OSAHS were treated by DO. All the patients received PSG and MSCT examination before and after DO to evaluate the therapeutic effect and changes in the upper airway.</p><p><b>RESULTS</b>According to the evaluation standard, 17 cases were cured and 2 cases improved markedly. The sagittal distance and area, transverse distance and area of the upper airway increased markedly after DO. The volume of upper airway increased from (15 572.03 +/- 3 370.11) mm3 to (21 182.69 +/- 4 533.15) mm3.The airway change happened mainly in velopharyngeal region and the lingopharyngeal region, but not in the laryngopharyngeal region.</p><p><b>CONCLUSIONS</b>DO can treat severe mandibular micrognathia patients with OSAHS effectively by enlarging the volume of upper airway,especially in the velopharynx and glossopharyngeum region. The MSCT plays an effective and important role.</p>