Background Outcomes of surgical management of obstructive sleep apnea-hypopnea syndrome (OSAHS) can be difficult to predict preoperatively. Aims/objectives To study the effect of applying traction to the velum during drug-induced sleep endoscopy (DISE) in OSAHS patients, and to describe the use of traction velum in predicting surgical success. Materials and methods 41 adult surgical patients with OSA (Friedman tongue position II and III) were evaluated by DISE. All patients subsequently underwent velopharyngeal surgery in the form of uvulopalatopharyngoplasty with tonsillectomy plus barbed reposition pharyngoplasty. Results Surgical responders (n = 26, 63.4%) and nonresponders (n = 15, 36.6%) demonstrated no significant differences with regard to preoperative AHI, age, sex, body mass index, and mean/lowest O2 saturation. Responders had a marked decrease in desaturation events (2.96 vs 0.03,p < 0.001) and percentage change in number of desaturation events before/after traction velum (56.7 vs 4.5,p < 0.001). Regression analysis revealed that reduction in mean desaturation events, with traction velum, by a percentage > 26.8% (odds ratio [OR] 1.046; 95% confidence interval [CI] 1.018-1.075;p = 0.001) was the only independent predictor of surgery success. Conclusions and significance OSAHS patients' velopharyngeal surgical outcome can be predicted by measuring the percentage change in the number of oxygen desaturation events before and after traction velum in DISE.