Limitations
Several factors must be understood when interpreting the results of this study. While the largest study included 168 patients the majority had less than 15 subjects. Additionally, all but one of these studies were retrospective reviews. There was also heterogeneity among the studies with some measuring a more obese and medically complex patients, multilevel airway surgery, and PSG results as secondary outcomes. This was accounted for in our statistical process described above. Within each study, demographic data and multi-level surgical targets were not always clearly linked to PSG data, presenting a source of confounding bias and potential selection bias. Finally, postoperative PSG data was collected on average 2.1 months postoperatively which may not be enough time to permit healing leading to possible under or over-estimation of OSA.2