Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 1 4 2017 04 09 148 150 EN Amin Amali Otorhinolaryngology Research Center AND Department of Otolaryngology, Head and Neck Surgery, School of Medicine AND Occupational Sleep Research Center, Baharloo Hospital, Tehran University of Medical Sciences, Tehran, Iran Behrooz Amirzargar Otorhinolaryngology Research Center AND Department of Otolaryngology, Head and Neck Surgery, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Mohammad Sadeghi Otorhinolaryngology Research Center AND Department of Otolaryngology, Head and Neck Surgery, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Babak Saedi Otorhinolaryngology Research Center AND Department of Otolaryngology, Head and Neck Surgery, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2016 09 16 2016 11 15 Background and Objective: Numerous anatomical abnormalities or pathological conditions can cause upper airway obstruction in obstructive sleep apnea syndrome (OSAS). Muller’s maneuver (MM) is one of diagnostic modalities investigating the obstruction site in patients with OSAS. This study aimed to investigate the obstruction sites of patients with OSAS based on MM. Materials and Methods: This was a case-series study. A total of 145 patients were enrolled in this study. The awake MM (a flexible fiberoptic endoscopy of the upper airway while patients perform forced inspiration against a closed oral and nasal airway) was performed by a single surgeon with the patient in a supine position. Endoscopic findings were classified using the modified velum, oropharyngeal lateral walls, tongue base, and epiglottis (VOTE) classification criteria. Results: Mean ± standard deviation age of patients was 41.5 ± 10.1 years old. Mean respiratory disturbance index was 29.7 ± 24.3/hours. The most common site of obstruction in all patients was velum. About 72% of the patients had more than 75% obstruction in the velum area while most patients had < 50% obstruction in oropharyngeal lateral walls (41.4%) and tongue base (55.2%). 69% of the patients had no obstruction in epiglottis according to the modified VOTE classification. Conclusion: Simple awake diagnostic test before surgery would help physicians to identify obstruction sites of OSAS patients. https://jss.tums.ac.ir/index.php/jss/article/view/44 https://jss.tums.ac.ir/index.php/jss/article/download/44/51