RESULTS: Total number of patients with OSA was 123. Forty-one (33.3%) patients had documentation of functional nasal obstruction (cases). The mean age of the patients was 55.5±11.5 years, and 50% were males. There was no statistically significant difference for age and sex between the two groups. Body mass index (BMI) was significantly lower in cases (28±4.6 vs 30.4±5.3 kg/m2), and Epworth Sleepiness score (ESS) significantly higher (10±5 vs 8±4, p-value <0.05). There were no differences in the baseline results of overnight oximetry, PSG, continuous positive airway pressure (CPAP) intolerance, and pressure requirement between the 2 groups. Repeat PSG was performed in 7 cases and 9 controls while utilizing MRA. The overnight oximetry did not correlate with severity of residual disease on PSG. The cases had higher overall and supine apnea-hypopnea index, and respiratory disturbance index as compared to controls with median and interquartile range of 14(0-31) vs 3(0.75-8.5), 42(1-77) vs 7(0.5-28), and 18(7-30) vs 7(3.5-27) respectively. Statistically significant difference could not be derived due to small numbers of the patients in each group.