Objectives: The purpose of this study was to evaluate the changes of position during sleep as determined by polysomnography before and after upper airway surgery for obstructive sleep apnea syndrome in patients with no response to surgery ("nonresponse group") and in those who did have a response to surgery ("response group").
Methods: We analyzed a total of 106 polysomnograms from 53 subjects and compared the preoperative-postoperative differences in the frequency of positional changes during sleep and the distribution of sleep positions between the nonresponse group (n = 25) and the response group (n = 28). Surgical response was defined as a greater than 50% decrease in the postoperative apnea-hypopnea index.
Results: The positional change index in the response group was significantly reduced (from 4.2 +/- 3.8 to 2.6 +/- 1.6; p = 0.038), whereas the positional change index in the nonresponse group did not significantly change (from 3.4 +/- 2.0 to 3.4 +/- 2.1; p = 0.861). The proportion of sleep time spent in the supine position did not significantly change in the nonresponse group (from 62.4% +/- 18.1% to 60.5% +/- 21.3%; p = 0.904) or the response group (from 55.5% +/- 23.9% to 60.1% +/- 23.1%; p = 0.412).
Conclusions: The frequency of positional changes during sleep was significantly decreased with the improvement of respiratory disturbances and arousals in the response group after upper airway surgery.