Will surgery be performed on multiple sites? Is sleep apnea usually a multi-location blockage or a single-location blockage? Will surgery be performed on multiple sites? The pharyngeal cavity is surrounded by soft tissues on three sides, and only the posterior pharyngeal wall is a bony structure. When a person falls asleep, the muscles relax and the soft tissues collapse downward, blocking the airway. The core of the palatopharynx can be blocked from the top to the bottom, with a shorter blockage in light cases and a longer blockage in heavy cases. Multiple structures can be involved in airway obstruction, including the uvula, soft palate, tongue, and even structures below the tongue root. In terms of the cause of airway obstruction, hypertrophy of the soft palate can lead to obstruction, and if the bony structure is not good, the attachment point of the soft palate can also lead to obstruction. The same is true for the tongue, which also has both hypertrophy and a posterior point of attachment. Therefore, the causes of sleep apnea include soft airway blockage and bony airway blockage. Some patients have to address the soft palate, while others have to address both the soft palate and the tongue, and different procedures address different degrees and characteristics of apnea. What tests are done before surgery? The first is polysomnography. The second is an upper airway CT to evaluate the entire upper airway structure, including the soft tissue and bony structures, to help select the surgical approach. The upper airway CT scans the nasal cavity, pharyngeal cavity, and soft palate, and then performs a three-dimensional reconstruction of the scans to see where the reconstructed airway is narrow and where the surgery should be targeted: whether it is the soft palate or the tongue, whether the jaw should be moved, whether the bony structures of the hard palate are narrow, whether the tonsils should be removed, etc. The third is a fiberoptic laryngoscopy, which looks at the cross-sectional area of the pharyngeal cavity through a mirror. Another commonly done test is esophageal manometry, which assesses the plane of airflow obstruction, whether it is upper or lower airway obstruction, nasopharyngeal plane obstruction or soft palate plane obstruction, to help choose the surgical approach. Do I still need to do this esophageal manometry after having an upper airway CT? Prof. Jing-Ying Ye: The role of esophageal manometry is different from that of upper airway CT, in that esophageal manometry can determine more clearly which plane is obstructed, while CT can visualize which area is narrowed.