Abstract: Objective To analyze the risk factors of difficult laryngeal exposure (DLE) in laryngeal surgery and the application of adjustable support laryngoscope. Methods The data of patients who were diagnosed with benign vocal cord lesions in our hospital from December 2020 to December 2021 and ordered minimally invasive laryngeal surgery with support laryngoscope were collected. Univariate and multivariate analyses were conducted to identify risk factors for DLE. An adjustable support laryngoscope was applied for DLE patients. Results Of the 48 patients with DLE, 45 (93.75%) were successful operations via adjustable support laryngoscopy, and 3 were converted to electronic laryngoscopy for the procedure. Univariate analysis showed that body mass index (BMI), neck circumference, sternomental distance (SMD), hyoid-mental distance (HMD), thyromental distance (TMD), tongue thickness, condyle range of motion, Yamamoto grade, and MMT grade were associated with DLE (P<0.05). Multiple logistic regression analysis showed that BMI≥25 kg/m², neck circumference≥40 cm, TMD<7 cm, tongue thickness≥60 mm, and condyle range of motion≥10 mm were the influencing factors of DLE. The ROC curve of the influencing factors showed that the areas under the ROC curve of the condyle range of motion and tongue thickness were 0.881 and 0.845 respectively. Conclusion BMI, neck circumference, TMD, tongue thickness, and condyle range of motion can be used as predictors of DLE, and tongue thickness and condyle range of motion can be independent predictors of DLE. For DLE patients, most surgeries can be done with an adjustable support laryngoscope.

Key words: Adjustable support laryngoscope, Difficult laryngeal exposure, Risk factor