Effects of mandibular setback surgery on upper airway dimensions and their influence on obstructive sleep apnoea - a systematic review.

Background: Mandibular setback used to be the traditional treatment of choice for correcting mandibular prognathism. Nowadays, bimaxillary surgery is preferred. Several authors have asserted that mandibular setback causes a relative narrowing of the upper airway (UA) that could trigger obstructive sleep apnoea (OSA); however, its potential role in OSA development is still much debated. Another controversial subject is whether changes in airway space caused by the procedure are permanent.

Objectives: To ascertain the consequences for UA size and shape of mandibular setback surgery in comparison with bimaxillary surgery (maxillary advancement with Le Fort I and mandibular setback), and to analyse the changes in oximetric indices and their relationship with OSA.

Search Methods: A systematic review was made of the bibliography in 4 databases: Medline, Scopus, Embase and Cochrane.

Selection Criteria: Systematic reviews, meta-analyses, clinical trials and cohort and case-control studies of adults published in the past 15 years were included.

Data Collection And Analysis: The initial search yielded 668 articles, of which 498 were eliminated because of duplication and 123 on the basis of their titles and abstracts or summaries. The remaining 47 papers were read in their entirety, and 14 were included in the final selection.

Results: According to our observations, the nasopharyngeal space does not undergo significant changes after either of the two surgical procedures. In the oropharynx and hypopharynx, none of the measurements changed significantly with maxillary advancement; however, persistent and significant decreases in the area, horizontal linear dimensions, and volume of these spaces are encountered after mandibular setback alone. No long-term changes in oximetric indices were found.

Conclusions: Morphological changes are more pronounced following exclusively mandibular surgery. A decrease in the UA does take place but appears not to affect the patient's sleep quality. This study found no evidence to confirm that bimaxillary or mandibular orthognathic surgery predisposes to obstructive sleep apnoea development.