Study Design

This was a retrospective study that analyzed all DISE exams performed on OSA patients at the Stanford Sleep Surgery Clinic between June 1, 2013, and July 31, 2017, and was approved by the Institutional Review Board and Hospital Research Ethics Committee of Stanford Hospital and Clinics (Protocol 35054).

Individuals with an apnea-hypopnea index (AHI) ≥5 events/hour, recorded by overnight polysomnography (PSG) in the laboratory or through a home sleep test (HST), and also with continuous positive airway pressure (CPAP) intolerance, were included in the study. Individuals with a previous invasive treatment for OSA, such as UPPP, tongue base surgery (transoral robotic surgery, radiofrequency, or coblation), genioglossus advancement, or maxillomandibular advancement, were excluded.

The sample characteristics, including age, sex, body mass index (BMI), tonsil size (TS) grading, FTP grading, Epworth Sleepiness Scale (ESS) score, sleep study data such as AHI and oxygen desaturation index (ODI), lowest oxygen saturation (LSAT), and DISE findings were extracted from the Stanford Hospitals and Clinics electronic health record system (REDCap [Research Electronic Data Capture] and Epic) databases. The above-mentioned clinical features were compared between groups. The associations of UA collapse characteristics (sites, patterns and degree) and FTP grades I to IV were analyzed.