Changing of facial skeleton for treatment of obstructive sleep apnoea syndrome.

Obstructive sleep apnoea syndrome (OSAS) is a potentially life-threatening disorder. It is characterized by at least five episodes of apnoea or hypopnoea during sleep lasting for more than 10 seconds. Apnoea or hypopnoea are accompanied by respiratory efforts. Changes of the facial skeleton by mandibular or maxillo-mandibular advancement belong to surgical techniques which might affect moderate and severe OSAS. In the surgical procedure mandible alone or the upper and lower jaws are moved forward by at least 10 mm. Thus also muscles fixed to the facial skeleton and upper airway dilatators are moved forward. The discussion also mentions possible complications and limitations of this surgical technique.

The impact of Le Fort I advancement and bilateral sagittal split osteotomy setback on ventilation during sleep.

The impact of orthognathic surgery for class III malocclusion on ventilation during sleep was examined using a comparison of pre- and post-surgical respiratory parameters. 21 patients with both maxillary hypoplasia and mandibular excess underwent Le Fort I osteotomy and advancement together with bilateral sagittal split osteotomy (BSSO) setback. Respiratory parameters, ECG and position of the body were monitored before surgery and postoperatively after the fixation removal (mean 8.5 months). Average Le Fort I advancement was 4.44 mm, BSSO setback was 4.96 mm. Generally, the orthognathic procedure worsened breathing function during sleep, as reflected in significant increase of index of flow limitations and decrease in oxygen saturation. The posterior airways space decreased to 75% of its original volume, the distance between mandibular plane and hyoid bone increased to 133%. The results indicate that bimaxillary surgery for class III malocclusion increased upper airway resistance. A young person would probably be able to balance such a decline in respiratory function using different adaptive mechanisms, but the potential impact of orthognathic surgery on the upper airways should be incorporated in a treatment plan.