Change in position dependency in non-responders after multilevel surgery for obstructive sleep apnea: analysis of polysomnographic parameters.

This study was aimed to evaluate the change in positional dependency by analyzing polysomnographic data in non-responders who previously underwent multilevel surgery for obstructive sleep apnea. A total of 48 consecutive patients who had a <50% reduction of apnea/hypopnea index (AHI) and a postoperative AHI of ≤20 after multilevel surgery were enrolled in this study. Postoperative polysomnography (PSG) was carried out at least 6 months after surgical treatment, and both pre- and postoperative PSG data were analyzed. No significant differences were found in any of the measured polysomnographic parameters before and after multilevel surgery in non-responders. In position-dependent patients, supine AHI, non-supine AHI, supine oxygen desaturation index (ODI) and non -supine ODI did not significantly improve after surgery. However, non-supine AHI and non-supine ODI in non-position-dependent patients (NPPs) improved significantly. Ten of 15 initially NPPs had position dependency after surgery, increasing the proportion of PPs from 68.8% (33/48) to 83.3% (40/48). These results suggest that positional therapy may be a useful adjuvant therapy in non-responders with position dependency.