Evaluation of the clinical efficacy of nasal surgery in the treatment of obstructive sleep apnoea

Abstract

Study objectives

The aim of the study was to evaluate the clinical efficacy of nasal surgery in the treatment of obstructive sleep apnoea (OSA) by comparing the improvement of subjective symptoms and objective metrics before surgery and after 6 months of surgery.

Methods

Patients with the main complaint of nasal congestion combined with habitual snoring who were hospitalized and treated were selected. Patients underwent subjective symptom tests and objective indicator monitoring both before surgery and 6 months after surgery. Comparisons between groups were performed using the independent samples t-test.

Results

Subjective scale evaluations demonstrated that nasal congestion, daytime sleepiness, snoring, nose-related symptoms, and sleep symptoms in patients with simple snoring or with OSA were improved after nasal surgery. Additionally, vitality was improved in all groups except for the patients with simple snoring and emotional consequence was improved in patients with simple snoring and mild OSA. Objective evaluations indicated the apnoea-hypopnoea index (AHI), the thickness of the soft palate, and the maximum cross-sectional area of the sagittal plane of the soft palate decreased after surgery in patients with mild OSA. The lowest blood oxygen concentration (LSaO₂) and anteroposterior diameter of the soft palate increased after surgery in patients with mild OSA. The arousal index also significantly decreased in patients with mild and moderate OSA. The nasal cavity volumes (NCVs) and the nasal minimal cross-sectional areas (NMCAs) of all groups showed significant differences after surgery.

Conclusions

Nasal surgery can effectively improve nose and sleep symptoms in patients with simple snoring or with OSA. It can significantly reduce the nasal resistance and increase the ventilation volume.

Statement of significance

Obstructive sleep apnoea (OSA) is becoming a global health problem. OSA is associated with several coexisting conditions, reduced health-related quality of life, and impaired work productivity. This study performed nasal surgery on OSA patients with the main complaint of nasal congestion combined with snoring and patients with simple snoring to compare the improvement of subjective symptoms and objective metrics before and after surgery. We found that: (1) symptoms such as nasal congestion, daytime sleepiness or snoring were improved after nasal surgery; (2) the apnoea-hypopnoea index (AHI) and arousal index decreased after surgery in patients with OSA; (3) the nasal and oropharyngeal cavity volumes increased after surgery. These findings suggest that patients with OSA or with simple snoring could benefit from nasal surgery.

Introduction

Obstructive sleep apnoea (OSA) is the general term for a group of diseases characterized by repeated episodes of partial or complete collapse of the upper airway (apnoea and hypopnoea) and chronic intermittent hypoxia during sleep; it is usually accompanied by symptoms such as snoring, sleep structure disorder, daytime sleepiness, and trouble concentrating [1]. Epidemiological studies in other countries have shown that the prevalence of this disease is approximately 2%–4% [2]. In China, the overall prevalence of OSA in adults is 3.93% [3]. Studies have suggested that OSA is an independent risk factor for cardiovascular and cerebrovascular diseases, cognitive impairment, and metabolic syndrome. As a source of upper airway diseases, OSA treatment has great importance in the comprehensive prevention and control system of chronic diseases [4], [5].

The pathogenesis of OSA involves many factors, including anatomical abnormalities of multiple planes of the airway, neuromuscular dysfunction, and abnormal stability of ventilation control. Stenosis or obstruction of any part of the upper airway can cause the occurrence and development of OSA [6]. Therefore, many methods, including surgery, positive pressure ventilation, and oral conformity correction have been used to relieve multiplanar airway stenosis and obstruction in OSA.

Impaired nasal breathing can cause the occurrence and development of OSA. The possible mechanisms are unstable open-mouth breathing, reduced nasopharyngeal reflex, and increased airway resistance [7]. Because of the important roles of the anatomical structure and physical function of the nasal cavity in disease progression in OSA, many studies have focused on the effectiveness rate and action mechanism of nasal surgery in the treatment of OSA. Researches have considered that nasal surgery can help to improve the disease condition in OSA; however, the underlying mechanism is still not clear [8].

Currently, evaluations of surgical efficacy in OSA patients are mainly divided into subjective and objective evaluations. Subjective evaluation mainly uses scale evaluations. The scales provide a hierarchical stratification of the severity of symptoms perceived by patients and subdivide and quantify them to form a series of scientific and objective tables. The subjective scales include the Sino-Nasal Outcome Test (SNOT-20) [9], the Epworth Sleepiness Scale (ESS) [10], the Snore Outcomes Survey (SOS) and Spouse/Bed Partner Survey (SBPS) [11], and the nasal congestion visual analogue scale (VAS), which evaluates patients' degree of nasal congestion along with OSA. Objective evaluations mainly use polysomnography (PSG). In addition, acoustic rhinometry and nasal resistance are also used to measure nasal volume and nasal resistance. Upper airway 3-dimensional computed tomography (3D-CT) scans and aerodynamics studies are also used to measure relevant data and parameters.

Scholars have tried to perform nasal surgery on OSA patients in order to understand the effect of relieving nasal congestion using nasal surgery on the disease condition of OSA [12], [13], [14], [15], [16], [17]. However, the opinions of different scholars are not consistent. Some researchers considered that nasal surgery could relieve both the subjective and objective conditions of patients (including the apnoea-hypopnoea index (AHI) and ESS scores) [13], [14], [15], [16]. However, others reported that nasal surgery did not relieve the objective conditions of patients and might even aggravate objective indicators of disease [12], [17]. There were also various explanations for the separation of subjective and objective conditions. First, the demographic characteristics, upper airway anatomical conditions, and sleep apnoea index of the patients enrolled in each study were different. Next, nasal surgery performed on patients used different methods and had different ranges. Finally, the methods used to evaluate the subjective and objective conditions of patients were not consistent.

This study performed nasal surgery on OSA patients with the main complaint of nasal congestion combined with snoring and patients with simple snoring to compare the improvement of subjective and objective symptoms before surgery and after 6 months of surgery. The study further evaluated the clinical efficacy of nasal surgery.