The influence of position-dependency on surgical success in sleep apnea surgery — a systematic review

Purpose To evaluate the influence of position-dependency on surgical success of upper airway (UA) surgery in obstructive sleep apnea (OSA) patients. Methods Systematic review. Results Two prospective cohort studies and seven retrospective cohort studies were included in this review. Despite the importance of the subject, it remains unclear whether position-dependency is a predictor for surgical success. No differences were found in surgical success rate between non-positional (NPP) and positional (PP) OSA patients undergoing uvulopalatopharyngoplasty/Z-palatoplasty with or without radiofrequent thermotherapy of the tongue, isolated tongue base or multilevel surgery and hypoglossal nerve stimulation. In one study PP undergoing relocation pharyngoplasty had a greater chance of surgical success. In the majority of the remaining studies, surgical success was in favor of NPP. Furthermore, in the vast part of included studies, the effect of UA surgery was suggested to be greater in the lateral position than supine position. Conclusion Although preoperative characteristics in PP (e.g., lower BMI and AHI) seem to be in favor for higher surgical success compared to NPP, it remains unclear whether position-dependency is a predictor for surgical outcome. It is suggested that the largest differences and expected preoperative and postoperative changes occur in non-supine AHI. In PP, the preoperative non-supine AHI is already lower compared to NPP suggesting a lower chance of surgical success in PP.