Key points

Overview of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a major health problem in the United States. With a prevalence in middle-aged adults of 2% to 4% of the population, untreated OSA has been implicated in increased risk for cardiovascular disease, including hypertension and heart failure.

The standard test for diagnosis of OSA is polysomnography, which produces outputs on several physiologic variables. The apnea-hypopnea index (AHI), expressed as the number of apneas and hypopneas per hour of sleep, and respiratory disturbance index (RDI), expressed as the number of apneas, hypopneas, and respiratory effort–related arousals per hour of sleep are the most important reported measures of disease severity. In general, an AHI or RDI of 5 or greater connotes a diagnosis of sleep apnea, 5 to 14 is defined as mild disease, 15 to 29 as moderate disease, and 30 or greater as severe disease. The goal of treatment of OSA is improvement in quality of life and longevity. Secondary outcome measures include a reduction of AHI and RDI and other key variables, such as lowest oxygen saturation, (LSAT) or oxygen desaturation index (ODI) as measured on polysomnography.

The first-line and most common treatment of OSA is positive airway pressure (PAP) treatment. PAP is effective in reducing the AHI and RDI if used properly. However, the mask interface, air pressure required, and need to use a machine at the bedside all night lead to poor acceptance and compliance rates. Compliance with PAP was defined by Kribbs and colleagues as using PAP for at least 4 hours a night for at least 5 nights a week (or a total of 20 hours a week) and this definition has been accepted by the American Academy of Sleep Medicine, Centers for Medicare & Medicaid Services, and almost all third-party payers in the United States. Because normal sleep time is about 49 hours a week, the current definition of compliant therapy represents the use of PAP for 41% of normal sleep hours (20/49 = 41%). Published studies on PAP have shown that only 58% to 80% of patients accept PAP therapy, and that 49% of patients are compliant in the first month of therapy. The largest study to date, the Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blind, 2-arm, sham-controlled, multicenter trial on a total of 1516 enrolled subjects. In this study, Kushida and colleagues found when analyzing CPAP use over the prior month that the compliance rate at 6 months was only 39% in the active CPAP group. In addition, there are many patients who prefer other therapy besides PAP because of the social issues related to PAP use. PAP therapy options include continuous PAP (CPAP), bilevel positive airway pressure, and autoadjusting positive airway pressure. Adherence to therapy is similar with the various PAP modalities.

Patients cite several issues with PAP, including discomfort and inability to sleep while connected to an air pressure device. Heated and humidified air and adequate education improve patient compliance, but compliance rates remain low. Nasal obstruction is a common limitation to effective PAP use. Medical treatments for nasal obstruction are typically tried first but, when not effective, nasal surgery may be indicated.

In the medical literature, a surgical cure is generally defined as a greater than 50% reduction in AHI and a final AHI of less than 20/h, but any reduction in AHI represents a reduction of disease burden and, in theory, should result in an overall improvement in morbidity and mortality.

Overview of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a major health problem in the United States. With a prevalence in middle-aged adults of 2% to 4% of the population, untreated OSA has been implicated in increased risk for cardiovascular disease, including hypertension and heart failure.

The standard test for diagnosis of OSA is polysomnography, which produces outputs on several physiologic variables. The apnea-hypopnea index (AHI), expressed as the number of apneas and hypopneas per hour of sleep, and respiratory disturbance index (RDI), expressed as the number of apneas, hypopneas, and respiratory effort–related arousals per hour of sleep are the most important reported measures of disease severity. In general, an AHI or RDI of 5 or greater connotes a diagnosis of sleep apnea, 5 to 14 is defined as mild disease, 15 to 29 as moderate disease, and 30 or greater as severe disease. The goal of treatment of OSA is improvement in quality of life and longevity. Secondary outcome measures include a reduction of AHI and RDI and other key variables, such as lowest oxygen saturation, (LSAT) or oxygen desaturation index (ODI) as measured on polysomnography.

The first-line and most common treatment of OSA is positive airway pressure (PAP) treatment. PAP is effective in reducing the AHI and RDI if used properly. However, the mask interface, air pressure required, and need to use a machine at the bedside all night lead to poor acceptance and compliance rates. Compliance with PAP was defined by Kribbs and colleagues as using PAP for at least 4 hours a night for at least 5 nights a week (or a total of 20 hours a week) and this definition has been accepted by the American Academy of Sleep Medicine, Centers for Medicare & Medicaid Services, and almost all third-party payers in the United States. Because normal sleep time is about 49 hours a week, the current definition of compliant therapy represents the use of PAP for 41% of normal sleep hours (20/49 = 41%). Published studies on PAP have shown that only 58% to 80% of patients accept PAP therapy, and that 49% of patients are compliant in the first month of therapy. The largest study to date, the Apnea Positive Pressure Long-term Efficacy Study (APPLES) was a 6-month, randomized, double-blind, 2-arm, sham-controlled, multicenter trial on a total of 1516 enrolled subjects. In this study, Kushida and colleagues found when analyzing CPAP use over the prior month that the compliance rate at 6 months was only 39% in the active CPAP group. In addition, there are many patients who prefer other therapy besides PAP because of the social issues related to PAP use. PAP therapy options include continuous PAP (CPAP), bilevel positive airway pressure, and autoadjusting positive airway pressure. Adherence to therapy is similar with the various PAP modalities.

Patients cite several issues with PAP, including discomfort and inability to sleep while connected to an air pressure device. Heated and humidified air and adequate education improve patient compliance, but compliance rates remain low. Nasal obstruction is a common limitation to effective PAP use. Medical treatments for nasal obstruction are typically tried first but, when not effective, nasal surgery may be indicated.

In the medical literature, a surgical cure is generally defined as a greater than 50% reduction in AHI and a final AHI of less than 20/h, but any reduction in AHI represents a reduction of disease burden and, in theory, should result in an overall improvement in morbidity and mortality.

The role of the nose and nasal obstruction in obstructive sleep apnea

Nasal obstruction is a common complaint in patients with sleep disordered breathing, occurring in up to 45% of patients. Nasal airway resistance is responsible for approximately two-thirds of total airway resistance. Increasing nasal resistance and nasal obstruction may be caused by a deviated septum, turbinate hypertrophy, internal or external nasal valve collapse, nasal mucosal inflammation, or space-occupying lesions in the nose ( Table 1 ). Airway resistance is proportional to the length of the airway and inversely proportional to the fourth power of the radius. As a result, a very small change in the size of the nasal airway caused by a septal spur, turbinate enlargement, internal or external nasal valve collapse, nasal polyp, or diffuse inflammation can cause a very large increase in nasal airway resistance. The anterior nasal cavity has more effect on nasal airway resistance than the posterior nasal cavity because the smallest part of the airway is located anteriorly at the level of the internal nasal valve.

Nasal obstruction may cause or exacerbate sleep disordered breathing in many ways, including increasing upper airway resistance, causing sleep onset and sleep maintenance insomnia, worsening sleep fragmentation, increased work of breathing, and causing mouth breathing. In addition, nasal obstruction may reduce the stimulation of nasal receptors, leading to a depressed central respiratory drive and worsening of the AHI. Oral breathing is likely detrimental to sleep quality. Nasal breathing has been shown to improve minute ventilation and pharyngeal muscle activity, whereas oral breathing worsens it. Nasal breathing is also worse at night because of a circadian variation in nasal resistance, possibly caused by a combination of reduced serum cortisol levels at night and changes in cytokine levels during sleep. In addition, there is increased nasal mucosal and tissue congestion when sleeping because there are no valves in the veins of the head and neck and therefore venous pressure in the nose increases when recumbent.

Several studies have investigated the effects of nasal obstruction on sleep in otherwise normal subjects. Lavie and colleagues studied 10 normal young adults without any ear, nose, and throat abnormalities and found that partial and complete mechanical obstruction of the nasal passages led to a significant increase in the number of apneas during sleep, in the number of microarousals associated with nonapneic breathing, and in the amount of wake time during sleep. Other studies have found that nasal obstruction leads to increased apneas, hypopneas, arousals, awakenings, and sleep stage changes, and reduced delta sleep. Multiple studies have found a greater prevalence of sleep disordered breathing in patients with nasal inflammation, such as allergic rhinitis. Young and colleagues studied 911 patients with nasal congestion caused by allergic rhinitis, finding a higher risk of excessive daytime sleepiness, snoring, and nonrestorative sleep and a 1.8 times greater risk of having sleep disordered breathing. Several studies have shown that exacerbations of allergic rhinitis lead to an increase in sleep disordered breathing and disturbed sleep, and other epidemiology studies have shown that nasal obstruction seems to be an independent risk factor for snoring and OSA. Most importantly, increased nasal resistance has been associated with poor compliance with CPAP.

Nasal packing after nasal surgery has been shown to have an adverse effect on sleep disordered breathing. Suratt and colleagues studied 8 men with and without nasal packing and found an increase in the number of obstructive apneas and hypopneas per hour and, to a lesser extent, the number of minutes of central events per hour. Armengot and colleagues evaluated 40 patients treated with nasal packing for epistaxis, finding that 92.5% showed poorer oxygen saturation and 47% had severe desaturation. Desaturation was greater in obese patients. Friedman and colleagues studied 49 patients with sleep apnea who were undergoing nasal surgery. They did a sleep study on the first postoperative night with nasal packing in place and found that, compared with the preoperative sleep study, the RDI, snoring, and ODI worsened in patients with mild OSA but not in those with moderate or severe OSA. Similarly, Turhan and colleagues studied 43 patients after septoplasty and compared the effects on polysomnographic measures of packing versus a transseptal suture, and found that the packing caused a greater increase in AHI and greater decrease in oxygen desaturation after surgery than in patients having no packing.

Nasal surgery

Common nasal surgeries performed to improve nasal breathing and for sleep disordered breathing include septoplasty, turbinate reduction, and nasal valve reconstruction. Septoplasty involves straightening of the nasal septum. The procedure may be done under local or general anesthesia and a variety of techniques are used based on surgical training and type and position of the septal deviation. Reducing a few millimeters of anterior septal deviation has been shown to produce significant improvements in nasal airway resistance, whereas repair of a posterior septal deviation has a lesser effect on airway resistance.

Turbinate reduction involves a reduction in the size of the inferior or middle turbinates. The procedure may be done under local or general anesthesia and a variety of techniques are used. Techniques include partial resection, submucous resection, outfracture, surface cautery, submucosal cautery, laser treatment, radiofrequency treatment, and endoscopic excision of concha bullosa when a concha bullosa is present in the middle turbinate.

Nasal valve reconstruction involves reconstruction of the internal or external nasal valve. The procedure may be done under local or general anesthesia and a variety of techniques are used. These techniques include spreader grafts, ear cartilage Batten grafts, J flaps, and various intranasal and extranasal suture techniques. There is insufficient research on the individual surgeries to validate the efficacy of each procedure but all of them cause an increase in the nasal airway and reduced collapsibility of the nasal valves, and lead to a reduction in nasal airway resistance. It is likely than any nasal surgery that accomplishes these end points should have a similar effect on sleep apnea or CPAP compliance.

There are limited data on the effects of endoscopic sinus surgery on sleep apnea and it is not clear whether endoscopic sinus surgery alone has any direct impact on nasal airway resistance. However, when sinus surgery improves sinusitis, there is a secondary benefit of reducing inflammation in the nose, which improves nasal resistance.