[Mechanism analysis of the site, pattern, and degree of upper airway multiple plane collapse during drug-induced sleep endoscopy in patients with obstructive sleep apnea].
Objective: To assess the anatomical and genioglossus electromyography (ggEMG) indicators in obstruction patterns classified by the VOTE system. Methods: This prospective study was conducted from September 2019 to April 2023, with a total of 107 adult patients (101 males and 6 females) aged 20-59 (38.8±8.0) years old (AHI≥15 times/hour) diagnosed with moderate to severe obstructive sleep apnea (OSA) at Beijing Tsinghua Changgung Hospital. Each subject underwent 3-D upper airway computed tomography (UACT), drug-induced sleep endoscopy and intraoral surface ggEMG monitoring. Based on VOTE system, the characteristics of UA collapses were classified and compared. Statistical analysis was conducted by SPSS 21.0. Results: All 107 patients with moderate to severe OSA had complete collapse of the velopharynx airway (including 47 cases in anteroposterior collapse group, 10 cases in the lateral collapse group, and 50 cases in the concentric collapse group). Comparing patient data from three different collapse modes, it was found that the velum pattern groups showed no statistical ggEMG differences (P>0.05); however, the lateral group exhibited the narrowest velopharynx mLAT [AP: 14.45(12.0, 16.2) mm, Lat: 11.40(9.6, 14.4) mm, Con: 12.70(11.0, 15.8) mm,H=6.41, P=0.041], and largest glossopharynx mAP[AP: 11.90(9.0, 15.7) mm, Lat: 14.30(11.8, 20.3) mm, Con: 14.10(11.8, 16.9) mm,H=8.40, P=0.015]. We found that patients with complete oropharynx lateral walls and partial tongue base collapse tended to have a higher BMI [(29.43±3.35)kg/m2 vs.(26.70±2.53) kg/m2,t=-2.83, P=0.007], longer glossopharynx length [(25.94±5.80) mm vs. (20.90±5.48)mm, t=-2.60,P=0.014], narrower glossopharynx mLAT [(15.59±3.87) mm vs. (21.10±8.07) mm, t=2.59, P=0.017], and were more likely to combine ggEMG dysfunction during obstructive apnea events [R4,(0.02±0.01)vs.(0.01±0.01), t=2.08, P=0.045)]. Moreover, all patients were classified according to the degree of epiglottic collapse (including 31 cases of no collapse, 33 cases of patial collapse, and 43 cases of complete collapse). The complete epiglottic collapse group exhibited the narrowest velopharynx minimal cross-sectional airway area (H=11.01, P=0.004) and the narrowest glossopharynx anteroposterior airway dimensions (H=7.06, P=0.029) and the longest glossopharynx length (H=9.65,P=0.008), whereas, the group of no epiglottic collapse showed the lowest ggEMG activation while awake (R1,H=8.59,P=0.014) and during sleep-onset (R2,H=9.79,P=0.007). Conclusions: The multiple plane collapse of the UA under DISE is the result of the combined effects of anatomical and functional factors, while the VOTE system cannot accurately describe the impact of different anatomical and functional causes. Among them, the degree of oropharynx lateral walls, tongue base and epiglottic collapse can all be affected by the function of the genioglossus muscle. This study can provide a theoretical basis for the comprehensive etiological treatment of OSA patients with multiple plane collapse.