The purpose of this study was to investigate the relationship between various polysomnographic variables and the success of modified tongue base suspension combined with uvulopharyngopalatoplasty in patients with severe obstructive sleep apnea (OSA). A total of 90 patients who had apnea hypopnea index (AHI) >30 and had both oropharyngeal and hypopharyngeal obstruction were included in this prospective case series with planned data collection. All patients were assessed preoperatively and at the sixth postoperative month by polysomnography. The surgery was considered to be successful when a ≥50% reduction in the mean AHI to a final AHI of <20/h was obtained. Multiple logistic regression analyses were performed to determine the impact of variables on the surgical success. A total of 67 patients (74.4%) met the surgical success criteria. The univariate analysis revealed a relationship between success and AHI (P = 0.001), obstructive apnea duration (P = 0.001), sleep time with oxygen saturation below 90% (ST90) (P = 0.004), minimum O2 saturation (P = 0.0001), mean O2 saturation (P = 0.011), mean O2 desaturation (P = 0.0001), and oxygen desaturation index (P = 0.001). However, ST90 [OR (95% CI) = 1.40 (1.04-1.89), P = 0.023] was the only independent parameter predicting the surgical success in multivariate analysis. The ROC analysis revealed that the ST90 value of ≤36 min was the best cutoff value with 96.97% sensitivity (CI 89.5-99.6), 95.83% specificity (CI 78.9-99.9), 98.5% PPV (CI 91.6-100.0), and 92.0% NPV (CI 74.0-99.0). The stratification of patients with severe OSA according to the ST90 may allow better identification of patients in whom surgical success is probable.