Study Objectives The Sleep Apnea Multilevel Surgery (SAMS) trial found that modified uvulopalatopharyngoplasty with tonsillectomy (if tonsils present) combined with radiofrequency tongue ablation reduced obstructive sleep apnea (OSA) severity and daytime sleepiness in moderate-severe OSA. This study aimed to investigate mechanisms of effect on apnea-hypopnea index (AHI) reduction by assessing changes in upper airway volumes (airway space, soft palate, tongue, and intra-tongue fat). Methods This is a case series analysis of 43 participants of 51 randomized to the surgical arm of the SAMS trial who underwent repeat magnetic resonance imaging (MRI). Upper airway volume, length, and cross-sectional area, soft palate and tongue volumes, and tongue fat were measured. Relationships between changes in anatomical structures and AHI were assessed. Results The participant sample was predominantly male (79%); mean ± SD age 42.7 ± 13.3 years, body mass index 30.8 ± 4.1 kg/m2, and AHI 47.0 ± 22.3 events/hour. There were no, or minor, overall volumetric changes in the airway, soft palate, total tongue, or tongue fat volume. Post-surgery there was an increase in the minimum cross-sectional area by 0.1 cm2 (95% confidence interval 0.04–0.2 cm2) in the pharyngeal airway, but not statistically significant on corrected analysis. There was no association between anatomical changes and AHI improvement. Conclusions This contemporary multilevel upper airway surgery has been shown to be an effective OSA treatment. The current anatomical investigation suggests there are not significant post-operative volumetric changes associated with OSA improvement 6-month post-surgery. This suggests that effect on OSA improvement is achieved without notable deformation of airway volume. Reduced need for neuromuscular compensation during wake following anatomical improvement via surgery could explain the lack of measurable volume change. Further research to understand the mechanisms of action of multilevel surgery is required. Clinical Trial This manuscript presents a planned image analysis of participants randomized to the surgical arm or the clinical trial multilevel airway surgery in patients with moderate-severe obstructive sleep apnea (OSA) who have failed medical management to assess change in OSA events and daytime sleepiness. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=266019&isReview=true%20Australian%20New%20Zealand%20Clinical%20Trials%20Registry%20ACTRN12514000338662, prospectively registered on March 31, 2014.

中文翻译：

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多层次上气道手术对咽部结构影响的容积磁共振成像分析

研究目标 睡眠呼吸暂停多层次手术 (SAMS) 试验发现，改良悬雍垂腭咽成形术联合扁桃体切除术（如果存在扁桃体）联合射频消融术可降低中重度 OSA 的阻塞性睡眠呼吸暂停 (OSA) 严重程度和白天嗜睡。本研究旨在通过评估上气道容积（气道空间、软腭、舌头和舌内脂肪）的变化来研究对呼吸暂停低通气指数 (AHI) 降低的影响机制。方法 这是对 51 名随机分配到 SAMS 试验的手术组并接受重复磁共振成像 (MRI) 的 43 名参与者的病例系列分析。测量上气道体积、长度和横截面积、软腭和舌头体积以及舌头脂肪。评估了解剖结构变化与 AHI 之间的关系。结果 参与者样本以男性为主（79%）；平均 ± SD 年龄 42.7 ± 13.3 岁，体重指数 30.8 ± 4.1 kg/m2，和 AHI 47.0 ± 22.3 事件/小时。气道、软腭、总舌或舌脂肪体积没有或轻微的总体体积变化。手术后，咽气道的最小横截面积增加了 0.1 cm2（95% 置信区间 0.04-0.2 cm2），但在校正分析中没有统计学意义。解剖变化与 AHI 改善之间没有关联。结论 这种当代多级上气道手术已被证明是一种有效的 OSA 治疗方法。目前的解剖学研究表明，术后 6 个月的 OSA 改善没有显着的术后体积变化。这表明在没有显着气道体积变形的情况下实现了对 OSA 改善的影响。通过手术改善解剖结构后，清醒期间对神经肌肉代偿的需求减少可以解释缺乏可测量的体积变化。需要进一步研究以了解多级手术的作用机制。临床试验 本手稿对随机分配到手术组或临床试验多级气道手术的中重度阻塞性睡眠呼吸暂停 (OSA) 患者的参与者进行了计划的图像分析，这些患者的医疗管理未能评估 OSA 事件和白天嗜睡的变化。https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=266019&isReview=true%20Australian%20New%20Zealand%20Clinical%20Trials%20Registry%20ACTRN12514000338662,