Efficiency of bimaxillary advancement surgery in increasing the volume of the upper airways: a systematic review of observational studies and meta-analysis.

Postsurgical changes of the airways have become a great point of interest because it has been reported that maxillomandibular advancement surgery can improve or eliminate obstructive sleep apnea; however, its treatment effectiveness is still controversial. The purpose of this systematic review and meta-analysis was to assess the effectiveness of maxillomandibular advancement surgery to increase upper airway volume in adults, comparing before and after treatment. Bibliographic searches of observational studies with no restriction of year or language were performed in the electronic databases PubMed, Scopus, ScienceDirect and SciELO for articles published up to April 2015. After verification of duplicate records, 1860 articles were examined. Of these, ten met the eligibility criteria, of which three were excluded for having poor methodological quality. The other seven articles were included in the systematic review and six in the meta-analysis, representing 83 patients. One study whose data were not given in absolute values was excluded from the meta-analysis. The meta-analysis showed a statistically significant difference between the averages of upper airway volume before and after surgery {7.86 cm [95 % CI (6.22, 9.49), p = 1.00)}. Clinical evidence suggests that the upper airway volume is increased after maxillomandibular advancement surgery.