In this validity two-arm study, a total (n) patients will be included; all are diagnosed with OSA and will undergo surgical treatment after appropriate planning. Patients will be classified into two equal groups with allocation ratio (1:1). Patients of the study group will be examined after scanning with CBCT at both ends of expiration and inspiration and DISE. Control group patients will be examined by DISE only. After discussing the treatment plan with the patient and educating the patient with all the data needed, an arabic consent form will be signed by the willing participants.
These (n) patients will be selected by the ENT specialist according to the following;
* A multidisciplinary approach will be performed to diagnose OSA patients who are indicated for surgery. Firstly, a comprehensive assessment of patients' history will be performed; including evaluation of all risk factors and complete sleep history.
* Epworth Sleepiness Scale (ESS) which consists of eight section questionnaire that defines the frequency of an individual to fall asleep during regular daily activities will be obtained from the patients.
* Afterward, a proper physical examination will be performed including a thorough clinical examination of the oropharynx, nasopharynx, and hypopharynx to evaluate any anatomical abnormalities as impotency of the nasal airway, elongated soft palate or uvula, enlarged lingual tonsils, and any other pathological conditions of tongue, palate, and tonsils.
* Then, Polysomnography (PSG) (sleep study) will be performed to allow proper evaluation of normal and abnormal physiological sleep episodes. Apnea/Hypoapnea Index (AHI) will be reported to detect the severity of OSA and patients were classified into mild (AHI = 5-14/ hour), moderate (AHI = 15-30 / hour) and severe (AHI \>30 / hour).
* All patients in both groups will undergo upper airway surgery, DISE will be performed by the same ENT surgeon to detect the level of collapse in the upper airway which will be assessed by LwPTL and VOTE classifications, emphasizing on the primary structures contributing at upper airway collapse, either alone or in combination: the larynx, palate, tongue and pharyngeal lateral walls.
* Study group participants only will be scanned by CBCT twice; once at the end of inspiration and the other at the end of expiration while they are gently holding their breath for as long as possible.
* In the study group, surgical procedures decision will be taken after appropriate assessment to sites of collapse in CBCT views at both ends of expiration and inspiration vies in combination to DISE.
* Finally, strict post-operative instructions will be given to patients of both group and a 3 months follow up would be done.
