Upper airway obstruction source factor – nasal obstruction – After more than 20 years of clinical practice and related research: chronic sinusitis nasal polyps, allergic rhinitis and obstructive sleep apnea hypoventilation syndrome – are upper airway (upper airway) obstructive diseases characterized by nasal ventilation dysfunction as the source factor In addition to causing metabolic disorders in the body, they can complicate or aggravate the risk of developing chronic diseases such as hypertension, stroke, coronary heart disease and diabetes mellitus. Adenoid hyperplasia in childhood can cause recurrent infections of the nasal cavity and sinuses and obstruction of nasal airflow. Without timely diagnosis and treatment, it can cause open-mouth breathing in children, inducing acquired nasal and pharyngeal structural compliance narrowing changes, causing disuse narrowing of the nasal cavity, disproportionate ventilation, rapid cranial development after puberty, with the floor of the maxillary sinus significantly lower than the bottom of the nasal cavity, disproportionate maxillary sinus volume to nasal ventilation volume, narrow nasal ventilation cross-sectional area, resulting in hypoventilation, long-term open-mouth breathing, causing pharyngeal mucosa hypertrophy, tonsillar This can cause pharyngeal mucosa hypertrophy, tonsillar hyperplasia, posterior lingual tonsillar fall, etc. In addition, it can also cause the typical pathological changes of abnormal development of craniofacial structures such as misalignment of the mandibular joint bite and narrow jaw. Long-term presence can cause intermittent hypoxemia during sleep, leading to reduced cerebral cortex responsiveness to CO2 retention, causing or aggravating neuromuscular regulatory dysfunction, and worsening upper airway ventilation function. Thus, it is essential that the timing of preventive interventions targeting source factors begins in childhood. It is important to maintain a uniform symmetry of the nasal ventilation function on both sides of the structure while maintaining normal physiological requirements. The spacious lateral nasal sinuses of patients with deviated nasal septum are more prone to the phenomenon of obstructive inflammation, which may be related to the compliance hyperplasia of one side of the structure triggered by bilateral nasal airflow asymmetry. To reduce hyperventilation, structures such as the ipsilateral septum, inferior turbinate, and middle turbinate, become progressively hyperplastic or hypertrophic. And the nasal ventilation on the deviated side decreases, causing obstruction and gradual atrophy of the structures. Long-term nasal airflow deviation can also cause dryness and discomfort symptoms in the pharyngeal cavity, followed by asymmetric compliance changes on both sides of the pharyngeal cavity, which can also further lead to laryngeal node deviation, asymmetric vocal fold development, thickening on one side and thinning on the other, perhaps the cause of hoarseness, precipitating vocal fold polyps or the phenomenon of pronunciation fatigue. Nasal dilation technique 1. Nasal dilation surgery: It is the main method to solve the source factor of upper airway obstruction at present. It mainly targets nasal obstruction caused by abnormalities in the nasal septum and lateral wall structure of the nasal cavity. The choice of nasal dilation surgery should fully consider the relationship between structure, function and clinical symptoms, correct pathological changes in the nasal cavity and adjust the symmetrical distribution of airflow on both sides to maintain normal ventilation function. The nasal endoscopic techniques are applied to carry out correction of deviated septum, opening of septal sinus, maxillary sinus and frontal sinus, correction of structural abnormalities of the lateral wall of nasal cavity, such as pneumatization of middle turbinate, paradoxical curvature of middle turbinate, hyperplasia and hypertrophy of inferior turbinate, adenoidectomy, etc. Nasal septum correction surgery should follow the treatment principles of preserving the integrity of the bony scaffold as much as possible and focusing on releasing the abnormal tension generated during the growth of the nasal septum, so as to maintain the proper biomechanical supportiveness of the septum and avoid subsequent nasal dorsal collapse. For example, the nasal septum trilinear subtension method [15]. Features: most of the nasal septal cartilage and normal bony scaffold are preserved, and only cartilage and bony parts in the area of the three tension lines are linearly removed. The first tension line: between the caudal end of the septal cartilage and the caudal end of the greater pterygoid cartilage of the nasal columella; the second tension line: where the septal cartilage joins the vertical plate of the sieve bone; and the third tension line: where the septal cartilage meets the plow bone, the nasal crest of the maxilla and the nasal crest of the jaw bone. If the cartilage of the preserved square is obviously deviated, grid-shaped scoring can be performed on the depressed side; for the septal vertical plate with severe high deviation, it can be clamped with occlusal forceps to keep the fracture in the midline position without resection. 2, maintain bilateral nasal ventilation symmetry principle: In the past, in the surgical treatment of rhinosinusitis, often ignore the symmetry of bilateral structures should be maintained when opening the sinus cavity, resulting in asymmetric ventilation on both sides, postoperative patients often show a reflex headache caused by hyperventilation on one side, requiring re-operation to solve the symmetry problem is not a few. The principle of symmetry is even more important in nasal dilation for correction of nasal obstruction in sleep disorders. Of the many factors that cause narrowing and obstruction of the upper airway, the first element often originates first in the nasal cavity. Therefore, it is important to focus on upper airway obstruction from the source and to carry out nasal dilation for early interventional treatment of patients with mild to moderate sleep airway obstruction, which has important clinical applications.