Abstract
The aim of this study was to study the prevalence of obstructive sleep apnea syndrome in patients with nasal and nasopharyngeal pathologies. A total of 60 consenting patients between the age of 14 to 60 years with primary nasal and nasopharyngeal pathologies were taken up for the study. These patients underwent history taking, detailed clinical examination including BMI, diagnostic nasal endoscopy and overnight polysomnography. The polysomnography results of people with different pathologies were compared and analysed. Based on the analysis it was arrived that isolated pathologies like septal deviation, nasal polypi and adenoid hypertrophy provided a statistically significant association with occurrence and severity of OSA. Also, that patients with combined pathologies were more proportionately affected by OSA than those with isolated pathologies. Nasal and nasopharyngeal pathologies have significant association with obstructive sleep apnea syndrome and all patients with these pathologies need to undergo polysomnography along with other routine investigations.
Keywords: Polysomnography, Obstructive sleep apnoea, Snoring, Septal deviation, Nasal Polyps
Introduction
Snoring and sleep apnea has become common disorders in the recent times, affecting both men and women. It is also linked to an increased risk of motor vehicle accidents, impaired daytime performance and quality of life and increased mortality independent of comorbidities [1].
Risk factors include obesity, adenoid hyperplasia, inflammatory-airway disease, and craniofacial abnormalities [2]. Multilevel anatomical obstruction such as nasal, nasopharyngeal, oropharyngeal and hypopharyngeal levels may play a role in the pathogenesis of OSA [3–6]. Nasal obstruction leads to mouth breathing that might in turn destabilise the upper airway [7–9] and lead to or aggravate OSA. Various authors have supported the theory that nasal obstruction is a contributing factor in the pathogenesis of OSA despite numerous controversies [7–9].
Structural abnormalities of the nose (such as septum deviation, hypertrophy of the inferior turbinate and polypi in the nasal cavity) and nasopharynx (such as adenoid hypertrophy) can cause Obstructive sleep apnoea apart from other sino-nasal conditions like chronic rhinosinusitis. The effect of anatomical abnormalities of the nose on the sleep disorders has been analysed by different authors, who confirm an improvement in the number of apnoea/ hypopnoea episodes following surgical correction of nasal abnormalities (septoplasty or turbinoplasty) [7–9]. Hence this study aimed at determining the prevalence of obstructive sleep apnoea in patients with structural abnormalities of nose and nasopharynx.
Materials and Methods
This study was conducted in our institution from May 2021 to May 2022. Patients who attended our department during the study period and diagnosed with conditions such as septal deviation, inferior turbinate hypertrophy, nasal polypi, adenoid hypertrophy and combined pathologies and who were willing to give informed consent were included in the study and were subjected to detailed history taking, general examination, anthropometric examinations such as weight, height, neck, chest and abdominal circumference, BMI calculation and ENT examination. Patients were also subjected to diagnostic nasal endoscopy, video laryngoscopy, epworth’s sleepiness scoring and STOP BANG questionnaire. The study population was 60 and all the individuals were subjected to an overnight 8-hour polysomnography. Patients were made aware that their sleep will be monitored continuously.
Patients refusing to give consent for the above investigations, age below 14 years and above 60 years, with history of prior nasal surgeries, with lower airway diseases, with co morbid conditions and other diseases contributing to obstructive sleep apnoea syndrome were excluded from the study.
Methodology
For analysis, patients were grouped based on the nature of their pathology.
Group A consists of patients with isolated septal deviation. They were further divided using Mladina classification system of septal deviation [10].
Type I - Presence of a unilateral crest which does not disturb the function of the nasal valve.
Type II - Disturbance of the valve function is caused by the unilateral crest.
Type III - One unilateral crest at the level of the head of the middle nasal concha.
Type IV- S shaped deviation with two crests – one at the level of the head of the middle nasal concha, and the other on the opposite side in the valve area,
Type V - unilateral ridge on the base of the septum.
Type VI - unilateral sulcus running through the caudal-ventral part of the septum, while on the other side there is a ridge and accompanying asymmetry of the nasal cavity.
Type VII - A mix of types from I to VI.
Group B consists of patients with isolated inferior turbinate hypertrophy. They were further classified based on Hol and Huizing classification of inferior turbinate hypertrophy [11].
Type (1) Compensatory hypertrophy.
Type (2) Protruded turbinate.
Type (3) Hyperplasia of the turbinate head.
Type (4) Hyperplasia of the whole turbinate.
Type (5) Hyperplasia of the turbinate tail.
Group C consists of patients with isolated nasal polyposis. The Meltzer Clinical Scoring System was used to grade the polyp [12].
Grade 0 = no polyps,
Grade 1 = polyps confined to the middle meatus,
Grade 2 = multiple polyps occupying the middle meatus,
Grade 3 = polyps extending beyond middle meatus,
Grade 4 = polyps completely obstructing the nasal cavity)
Group D consists of patients with isolated adenoid hypertrophy. Adenoid hypertrophy classification was done as followed.
grade 1, adenoid occupying less than 25% of the choanal area.
grade 2, adenoid occupying 25–50% of the choanal area.
grade 3, adenoid occupying 50–75% of the choanal area.
grade 4, adenoid occupying 75–100% of the choanal area.
Group E consists of patients with combined pathologies.
The polysomnography assesses wakefulness and sleep stages, respiration, cardiopulmonary function, and body movements. Electroencephalography (EEG), electro-oculography (EOG), and chin muscle electromyography (EMG) channels were used to stage sleep. Airflow and respiratory effort channels were used to score sleep disordered breathing patterns, if any. The finger pulse oximetry channel provides additional data on sleep disordered breathing patterns and also in identifying sleep hypoxemia independent of apnoeic and hypopnea events.
Results and Analysis
Age distribution in our study group was 14 to 60 years and majority of them were in 31 to 40 years age group (36.67%). In our study population, 33(57%) were males and 27(33%) were females and 20(33%) were normal weight and 40 (67%) were in overweight category. Upon analysis, 40 patients (66.67%) had OSA. Mild OSA was more prevalent when compared to other forms. 27 (45%) patients had mild OSA, 7 (11.6%) had moderate OSA and 6 (10%) patients had severe OSA. 20 patients (33.37%) had no OSA.
Among the study population, 21 (35%) have isolated septal deviation. Septal deviation was further classified into types based on Mladina Classification system into seven types. Type II deviated septum was found to be the most common type among them and was seen in 5 patients.
Among the study population, 6 (10%) have isolated inferior turbinate hypertrophy. Inferior turbinate hypertrophy was further divided into 5 types. Type II and Type III were the commonest among with 2 patients each.
Among study population, 7 (11.67%) have isolated nasal polyp. Isolated nasal polypi were further divided into four types. All isolated nasal polypi in this study group were unilateral. Grade III forms the majority (6.67%).
In the study population, 6 patients (10%) have isolated adenoid hypertrophy. Adenoid hypertrophy was further classified into 4 grades. Grade II and IV were more common (3.33% each).
In our study population, 20 patients (33.33%) presented with combined pathology and 40 patients (66.67%) presented with isolated pathologies. Combination of the pathologies noted in the study population are distributed accordingly in the table above.
Among patients with combined pathologies, Type IV DNS and Type IV Inferior turbinate Hypertrophy forms the majority (8.33%).
Analysis of Distribution of Obstructive Sleep Apnoea among Various age Groups
In this study population, OSA was found to be more prevalent among the 31 to 40 age group and mild form was more common in this age group as noted in Table 1. On applying Chi square test there was no significant difference among different age group and severity of OSA.
Table 1.
Prevalence of OSA among different age groups
| Age Group | Obstructive Sleep Apnoea | |||
|---|---|---|---|---|
| Nil | Mild | Mod | Severe | |
| 14 to 20 | 4 | 3 | 2 | 0 |
| 21 to 30 | 10 | 7 | 1 | 1 |
| 31 to 40 | 4 | 13 | 2 | 3 |
| 41 to 50 | 0 | 3 | 2 | 2 |
| 51 to 60 | 2 | 1 | 0 | 0 |
Among the 27 females in the study population, OSA was prevalent in 16 females. Among the 33 males, OSA was prevalent in 24 patients. From this analysis, it is arrived that OSA was more prevalent in males and mild OSA was more common among them. On applying Chi square test there was no significant difference among different gender and severity of OSA. In this study, 20 patients were in the normal weight category and 40 were in overweight. Among them, OSA was more prevalent in the overweight population (48.33%).
Group A: Analysis of Prevalence of Obstructive Sleep Apnoea among Patients with Various Types of Isolated Deviated Nasal Septum
Among the 21 patients with isolated septal deviation, OSA was prevalent in 11 patients and mild form was more common in them as noted in Table 2. Three had moderate OSA and one patient had severe OSA. On applying Chi square test there was significant difference among different grades of septal deviation and severity of OSA.
Table 2.
prevalence of obstructive sleep apnoea among patients with various types of Isolated deviated nasal septum
| Septal deviation types | Obstructive sleep apnea | |||
|---|---|---|---|---|
| Normal | Mild | Moderate | Severe | |
| Type I | 3 | - | - | - |
| Type II | 5 | - | - | - |
| Type III | 1 | 3 | - | - |
| Type IV | - | 3 | 1 | - |
| Type V | - | - | 1 | 1 |
| Type VI | 1 | - | - | - |
| Type VII | - | 1 | 1 | - |
| Total | 10 | 7 | 3 | 1 |
Group B: Analysis of Prevalence of Obstructive Sleep Apnoea Among Various Types of Isolated Inferior Turbinate Hypertrophy
Among 6 patients with isolated inferior turbinate hypertrophy, none had OSA. On applying Chi square test there was no significant difference among different grades of turbinate hypertrophy and severity of OSA as discussed in Table 3.
Table 3.
Prevalence of obstructive sleep apnoea among various types of isolated inferior turbinate hypertrophy
| Inferior turbinate hypertrophy - types | Obstructive sleep apnea | |||
|---|---|---|---|---|
| Non OSA | Mild | Moderate | Severe | |
| Type 1 | - | - | - | - |
| Type 2 | 2 | - | - | - |
| Type 3 | 2 | - | - | - |
| Type 4 | 1 | - | - | - |
| Type 5 | 1 | - | - | - |
| Total | 6 | 0 | 0 | 0 |
Group C: Prevalence of Obstructive Sleep Apnoea among Various Grades of Isolated Nasal Polyposis
Among 7 patients with isolated unilateral nasal polypi, all had varying forms of OSA. Three patients had mild OSA, two had moderate and one had severe OSA. On applying Chi square test there was significant difference among different grades of polyps and severity of OSA, higher grade polyps have more severe OSA as discussed in Table 4.
Table 4.
Prevalence of obstructive sleep apnoea among various grades of isolated nasal polyposis
| Nasal polyposis | Obstructive sleep apnoea | |||
|---|---|---|---|---|
| Nil | Mild | Mod | Severe | |
| POLYP – I | 0 | 0 | 0 | 0 |
| POLYP - II | 0 | 1 | 0 | 0 |
| POLYP - III | 0 | 2 | 2 | 0 |
| POLYP - IV | 0 | 0 | 0 | 2 |
| TOTAL | 0 | 3 | 2 | 2 |
Group D: Prevalence of Obstructive Sleep Apnoea among Various Grades of Isolated Adenoid Hypertrophy
Among the 6 patients with adenoid hypertrophy of various grades, OSA was prevalent in 3 patients had and 3 had no OSA. On applying Chi square test there was significant difference among different grades of adenoids and severity of OSA in that higher grade of adenoid hypertrophy has more severe OSA as discussed in Table 5.
Table 5.
Prevalence of obstructive sleep apnoea among various grades of isolated adenoid hypertrophy
| Adenoid hypertrophy | Obstructive sleep apnoea | |||
|---|---|---|---|---|
| Nil | Mild | Mod | Severe | |
| Adenoid-I | 1 | 0 | 0 | 0 |
| Adenoid-II | 2 | 0 | 0 | 0 |
| Adenoid-III | 0 | 1 | 0 | 0 |
| Adenoid-IV | 0 | 0 | 2 | 0 |
| Total | 3 | 1 | 2 | 0 |
Group E: Distribution of Obstructive Sleep Apnoea and its Various Severity Among Isolated and Combined Pathologies
Among the 20 patients with combined pathologies, OSA was prevalent in 19 patients and 1 patient was normal. Among the 40 patients with isolated pathologies, OSA was prevalent in 21 patients and 19 patients were normal which can be noted in Fig. 1. On applying Chi square test there was significant difference among different pathologies and severity of OSA. In patients with isolated pathology, majority does not have OSA and in patients with combined pathology, majority have mild OSA.
Fig. 1.
Obstructive sleep apnoea among isolated vs combined patholgie
Among patients with combined pathologies, septal deviation with inferior turbinate hypertrophy of various grades had the highest prevalence of mild OSA as noted in Table 6; Fig. 2.
Table 6.
Prevalence of OSA among various combined and isolated pathologies
| Findings | Obstructive Sleep apnoea | |||
|---|---|---|---|---|
| Nil | Mild | Mod | Severe | |
| DNS-I/ITH-I | 1 | 0 | 0 | 0 |
| DNS-III/ITH-IV | 0 | 4 | 0 | 0 |
| DNS-IV/ITH-IV | 0 | 5 | 0 | 0 |
| DNS-V/ITH-III | 0 | 3 | 0 | 0 |
| DNS-V/POLYP-IV | 0 | 0 | 0 | 2 |
| DNS-VII/ITH-III | 0 | 4 | 0 | 0 |
| DNS-VII/ITH-IV | 0 | 0 | 0 | 1 |
| Single | 19 | 11 | 7 | 3 |
Fig. 2.
Severity of OSA among single/combined pathology
Discussion
Among the study population, OSA was prevalent in 80% and mild OSA was the commonest among them (45%).
It has been demonstrated in many studies that gender plays an important role in influencing the variables involved in pathogenesis of OSA. In this study, OSA was present in both males and females and there is no statistically significant difference among gender and severity of OSA. In a literature review conducted by Christine.M Lin et al. [13], OSA was found to be more common in men than women. Men and women often differed in their presenting complaints of OSA with women mainly complaining of insomnia and depression. This leads to the possibility that women are underdiagnosed when it comes to OSA. Even though this literature review is in contrast to our study, the possibility of women being underdiagnosed might account for the contradiction.
In this study, even though the majority of the age groups were affected with mild OSA, on applying Chi square test there was no significant difference among different age group and severity of OSA.
In a study conducted by Deng X et al. [14] among males the severity of OSA increased in those aged ≤ 40 years and in their female population, age was associated with OSA severity in three age groups with a positive correlation in the age group of 45– 53 years.
In this study, in order to exclude other contributing factors of OSA such as obesity, patients with BMI greater than or equal to 30 were excluded. It was observed that OSA is more prevalent in people with overweight BMI.
Group A – Discussion on OSA in Patients with Isolated Septal Deviation
As per the update on the subject matter by Georgalas C [15], septal deviation causes two main changes in the air airway. It increases the nasal resistance that leads to increase in the negative suction force in the oropharyngeal airway. It also causes mouth breathing leading to breathing through the unstable oral airway that causes increased total airway resistance. In our study population, it was noted that Type IV septal deviation was more associated with OSA. The mean value of AHI observed in patients with isolated septal deviation was 9.39 that lies in the mild OSA category.
Sang Woo Yeom et al. [16] investigated the prevalence of OSA in patients with septal deviation using a 9-year large-scale cohort study. It was concluded from a long-term follow-up, that the prevalence of OSA was found to be 4.39 times higher in the septal deviation group when compared with the control group.
In a study conducted by Lavie. P et al. [17], it was observed that unilateral or bilateral nasal occlusion contributes to increased apnoea during sleep. In acceptance with the above study, the mean value of AHI in our study population with septal deviation was 9.39 and ranged from 2.35 to 27.08 with majority of the values lying in the mild and then moderate AHI range, suggesting that septal deviation could be a cause for the increase in AHI.
Group B – Discussion on OSA in Patients with Isolated Inferior Turbinate Hypertrophy
The head of the inferior turbinate forms the inferior part of the internal nasal valve which is the narrowest portion of the nasal cavity offering high nasal resistance [18]. Any anatomical or dynamic obstruction occurring at the internal nasal valve causes a further more increase in the nasal resistance and is proposed to cause oropharyngeal airway collapse as per the Starlings resistor model. In patients with isolated inferior turbinate hypertrophy, no patients have Obstructive sleep apnoea. The mean value of AHI in patients with isolated inferior turbinate hypertrophy was 2.51 that also lies in the normal range.
The above findings are in correlation with the study conducted by H Lenders et al. [19] in which nasal resistance was calculated using Acoustic rhinometry in patients with turbinate hypertrophy. It was observed that even though nasal resistance was found to be increased in patients with snoring and OSAS, there was no positive correlation between the nasal resistance and RDI.
Group C – Discussion on OSA in Patients with Isolated Nasal Polyposis
Bilateral or unilateral polypi of varying grades causes nasal obstruction and decreased activation of nasal receptors. This leads to inhibition of muscle tone, respiratory rate and minute ventilation. It also causes decreased concentration of Nitric oxide with reduced ventilation perfusion ratio [20]. This also may lead to Obstructive sleep apnoea.
In our study, 7 (11.6%) of the population have isolated nasal polyposis. All 7 patients presented with unilateral polypi. Among them, Obstructive sleep apnoea was prevalent in all patients (100%). Mild OSA had a prevalence of 42.85% (3 patients), moderate OSA had a prevalence of 28.57% (2 patients) and severe OSA had a prevalence of 28.57% (2 patients). And grade III polyposis was more associated with OSA in this study population. The mean value of AHI in patients with isolated nasal polypi was 25.97, lying in the moderate range.
Migueis D.P et al. [21] conducted a cross sectional study that included 47 male patients with chronic rhinosinusitis with sinonasal polyposis and subjected them to level 1 polysomnography. It was observed that OSA in these individuals were frequent. These findings are in correlation with the observation made in our study.
Group D – Discussion on OSA in Patients with Isolated Adenoid Hypertrophy
In our study population, 6 (10%) have adenoid hypertrophy. Among them, OSA was prevalent in 3 (50%) patients. The mean value of AHI in this population was 8.98, lying in the mild range.
Kang KT et al. [22] conducted a study to investigate the association of adenoid and tonsil size to childhood obstructive sleep apnea (OSA) among other aims. It was noted that there was a positive correlation between adenoid size and AHI in the age groups of toddlers, preschool and school group children but not in the adolescent group.
A similar study by Taluker DC et al. [23] arrived at a similar conclusion as the above study, that AHI was positively correlated to tonsil and adenoid grade in all children. Tonsil grade was positively related to AHI in all four age groups. Adenoid grade was positively related to AHI in the toddler, preschool, school groups, but not in the adolescent group. These observations are similar to the one made in our study.
Group E - Discussion on OSA in Patients with Isolated and Combined Pathologies
The prevalence of OSA in patients with combined pathology were found to be more than that found in the patients with single pathology and majority with combined pathology had mild OSA. Even though the prevalence of OSA in patients with isolated inferior turbinate hypertrophy was nil, OSA was more prevalent when inferior turbinate hypertrophy was presented together with septal deviation and this could possibly be due to the combined nasal obstruction caused by the two pathologies.
In a study conducted by Magliulo et al. [24], assessing the nasal pathologies in patients with Obstructive sleep apnoea, it was concluded that one or more pathological rhino-sinusal conditions were present in almost 80% of patients with OSA and this finding is in correlation with our study. In a meta-analysis conducted by Wu et al. [25], studies involving isolated nasal surgeries for the treatment of OSA were considered and their results analysed. It was concluded that isolated nasal surgeries significantly improve the ESS and AHI scores of patients with OSA, thereby ruling out the misconception of nasal surgeries not playing a major role in OSA treatment. It is inferred from our study that the prevalence of OSA in patients with nasal pathologies were significantly more. These patients may be subjected to nasal surgeries in the future and the improvement in various OSA indices can be measured.
Other observations made in this study are,
The mean value of REM, N1, N2 and N3 stages of sleep in the study population are 1.5, 17.88, 26.13 and 16.12 respectively. These observations were compared with the study conducted by Svanborg E et al. [26].
Conclusion
It is concluded from this study that obstructive sleep apnoea syndrome is significantly prevalent in patients with primary nasal and nasopharyngeal pathologies. Isolated pathologies like septal deviation, nasal polypi and adenoid hypertrophy provided a statistically significant association with occurrence and severity of OSA. Patients with combined pathologies were more proportionately affected by OSA than those with isolated nasal or nasopharyngeal pathologies. Though there is no snoring and symptoms of OSA in these patients, there was subtle sleep apnoea. Hence all patients with nasal and nasopharyngeal pathologies need to undergo polysomnography along with other routine investigations and appropriate surgical or medical management can be performed in those with OSA to prevent them from developing complications of OSA. Studies can further be directed to treat patients with nasal and nasopharyngeal pathologies and an attempt to identify any significant changes in the indices of PSG can be made, that would eventually establish diagnosis and treatment of nasal and nasopharyngeal pathologies as an important factor in the treatment of Obstructive sleep apnoea syndrome.
Author Contribution
All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Dr. B. Shankameswaran and Dr. G. Viveknarayan. The first draft of the manuscript was written by Dr. B. Shankameswaran and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.
Funding
The authors did not receive support from any organization for the submitted work. Financial interests: The authors declare they have no financial interests. Non-financial interests: none.
Declarations
Ethical Approval
Institutional ethical committee approval was obtained and the study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.
Consent
Informed consent was obtained from the patients before the study.
Competing Interests
The authors have no competing interests to declare that are relevant to the content of this article.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Friedman’s sleep apnea and snoring: surgical and non-surgical therapy Chap. 2 pg. 3
- 2.Ballenger’s textbook of Otolaryngology Chap. 98, pg. 1279–1282
- 3.Friedman’s sleep apnea And snoring: surgical and non-surgical therapy chap. 2 pg. 4,5,6,7.
- 4.Scott-Brown’s Otorhinolaryngology Head & Neck surgery; 8th edition, volume 3, Chap. 73
- 5.Cummings textbook of Otorhinolaryngology 7th edition, Chap. 15
- 6.Ganong’s medical physiology 26th edition, Chap. 14
- 7.Obstructive sleep apnea Diagnosis and treatment. Clete A Kushida. Chapter 4, pg61–63
- 8.Mannarino MR, Di Filippo F, Pirro M (2012) Obstructive sleep apnea syndrome. Eur J Intern Med 23(7):586–593 [DOI] [PubMed] [Google Scholar]
- 9.Scott brown 8th edition, volume 1, Chap. 103, page 1137
- 10.Mladina R (1987) The role of maxillar morphology in the development of pathological septal deformities. Rhinology 25(3):199–205 [PubMed] [Google Scholar]
- 11.Huizing EZ, de Groot JAM, Sect. (2003) 8: Surgery of the Nasal Cavity: Turbinate Surgery. Functional Reconstructive Nasal Surgery, 2nd edition, Thieme, Stuttgart, pg. 276–282
- 12.Meltzer EO, Hamilos DL, Hadley JA, Lanza DC, Marple BF, Nicklas RA et al (2006) Rhinosinusitis Initiative. Rhinosinusitis: developing guidance for clinical trials. J Allergy Clin Immunol 118(5 Suppl):S17–61 [DOI] [PubMed] [Google Scholar]
- 13.Lin CM, Davidson TM, Ancoli-Israel S (2008) Gender differences in obstructive sleep apnea and treatment implications. Sleep Med Rev 12(6):481–496 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Deng X, Gu W, Li Y, Liu M, Li Y, Gao X (2014) Age-group-specific associations between the severity of obstructive sleep apnea and relevant risk factors in male and female patients. PLoS ONE 9(9):e107380 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Georgalas C (2011) The role of the nose in snoring and obstructive sleep apnoea: an update. Eur Arch Otorhinolaryngol 268(9):1365–1373 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Yeom SW, Kim MG, Lee EJ, Chung SK, Kim DH, Noh SJ, Lee MH, Yang YN, Lee CM, Kim JS (2021) Association between septal deviation and OSA diagnoses: a nationwide 9-year follow-up cohort study. J Clin Sleep Med 17(10):2099–2106 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Lavie P, Fischel N, Zomer J, Eliaschar I (1983) The effects of partial and complete mechanical occlusion of the nasal passages on Sleep structure and breathing in Sleep. Acta Otolaryngol 95(1–4):161–166 [DOI] [PubMed] [Google Scholar]
- 18.Patel B, Virk JS, Randhawa PS, Andrews PJ (2018) The internal nasal valve: a validated grading system and operative guide. Eur Arch Otorhinolaryngol 275(11):2739–2744 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Lenders H, Schaefer J, Pirsig W (1991) Turbinate hypertrophy in habitual snorers and patients with obstructive sleep apnea: findings of acoustic rhinometry. Laryngoscope 101(6 Pt 1):614–618 [DOI] [PubMed] [Google Scholar]
- 20.Michels Dde S, Rodrigues Ada M, Nakanishi M, Sampaio AL, Venosa AR (2014) Nasal involvement in obstructive sleep apnea syndrome. Int J Otolaryngol. ; 2014:717419 [DOI] [PMC free article] [PubMed]
- 21.Migueis DP, Lacerda GCB, Lopes MC, Azevedo-Soster LMSF, Thuler LCS, Lemes LNA, Araujo-Melo MH (2019) Obstructive sleep apnea in patients with chronic rhinosinusitis with nasal polyps: a cross-sectional study. Sleep Med 64:43–47 [DOI] [PubMed] [Google Scholar]
- 22.Kang KT, Chou CH, Weng WC, Lee PL, Hsu WC (2013) Associations between adenotonsillar hypertrophy, age, and obesity in children with obstructive sleep apnea. PLoS ONE 8(10):e78666 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Talukder Dc1, Aich Ml2, Alam Mr3, Islam Ms4, Mahmud S5, Biswas D6, Saha K7, Rahman F8. Associations between adenotonsillar hypertrophy, age, and obesity in children with obstructive sleep apnea J Dhaka Med Coll (2017) ; 26(2): 167–172
- 24.Magliulo G, Iannella G, Ciofalo A, Polimeni A, De Vincentiis M, Pasquariello B, Montevecchi F, Vicini C (2019) Nasal pathologies in patients with obstructive sleep apnoea. Acta Otorhinolaryngol Ital 39(4):250–256 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Wu J, Zhao G, Li Y, Zang H, Wang T, Wang D, Han D (2017) Apnea-hypopnea index decreased significantly after nasal surgery for obstructive sleep apnea: a meta-analysis. Med (Baltim) 96(5):e6008 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Svanborg E, Guilleminault C (1996) EEG frequency changes during sleep apneas. Sleep 19(3):248–254 [PubMed] [Google Scholar]