Classification of Sleep & Sleep Disorders
Sleep is a reversible physiologic and behavioral state that manifests as decreased awareness and reaction to external stimuli. Normal sleep architecture comprises two distinct phases: NREM (non-rapid eye movement) sleep which comprises 75–80% of sleep and occurs in four stages (Stages I–IV), whereas REM (rapid eye movement) sleep which comprises 20–25% of sleep and occurs in two stages. In a normal adult, these two phases of sleep occur in semiregular cycles, which last approximately 90–120 minutes and occur three to four times per night.
In the normal adult male, Stage I (N1) sleep, which is considered the transition to sleep, occupies 2–5% of sleep and is characterized by an increase in theta waves and a decrease in alpha waves on an electroencephalogram (EEG). Stage I sleep is also marked by a decrease in awareness and in muscle tone. Stage II (N2) sleep occupies 45–55% of sleep and is characterized by K-complexes and spindles on EEG as well as decreases in muscle tone and awareness. Stage II sleep is considered by most authorities to be the “true” onset of sleep. Stages III and IV (N3) sleep comprise deep sleep, and it occurs predominantly in the first third of the night. The hallmark of deep sleep is the abundance of delta waves on EEG. Stage III sleep occupies 3–8% of sleep, and Stage IV sleep occupies 10–15% of sleep. Stages III and IV are widely considered the most restful stages of sleep. With increasing age, deep sleep progressively occupies less and less of total sleep time.
The remaining portion of sleep is composed of REM sleep, which is divided into tonic and phasic stages. During the tonic stage, the EEG becomes asynchronous and muscles lose tone. The phasic stage of REM sleep is characterized by rapid eye movements as well as erratic cardiac and respiratory patterns.
Derangements in sleep are categorized by the American Sleep Disorders Association in the International Classification of Sleep Disorders (ICSD), which arranged sleep disorders into four categories: dyssomnias, parasomnias, sleep disorders associated with medical-psychiatric disorders, and proposed sleep disorders (Table 41–1).
Table 41–1. Classification of Sleep Disorders. ||Download (.pdf)
Table 41–1. Classification of Sleep Disorders.
- Circadian rhythm disorder
- Insomnia, narcolepsy, OSA
- Poor sleep hygiene
- Advanced or delayed sleep phase disorder
- Disorder of arousal
- Sleep–wake transition disorder
- Sleep walking, sleep terrors
- Sleep talking, nocturnal leg cramps
- Bruxism, infant sleep apnea
- Mental disorders
- Neurologic disorders
- Psychosis, anxiety disorders
- Dementia, fatal familial insomnia
- COPD, sleep-related GERD
|Proposed||Sleep hyperhidrosis, sleep-related laryngospasm|
The term apnea refers to a period of at least 10 seconds during which air flow is absent by nose or mouth. Apnea may be obstructive or central in origin. A hypopnea is a decrease in airflow to 10–70% of baseline for more than 10 seconds, associated with arousals or desaturation by at least 3%. The apnea hypopnea index (AHI) is the number of apneas and hypopneas per hour of sleep time and is based on a minimum of 2 hours of sleep. Many have debated the significance of this index because it does not reflect the absolute number of apneas and/or hypopneas, the duration of such events, or the distribution of such events during sleep. Some authors use the respiratory disturbance index (RDI), which is the AHI + arousal index, to help correlate with patient symptomatology.
Obstructive sleep apnea (OSA) is present when the AHI is ≥5 events/h. It is further classified as mild (5–15 events/h), moderate (15–30 events/h), and severe (>30 events/h). The obstructive sleep apnea syndrome (OSAS) is diagnosed when the AHI is >15 and the patient has nighttime and daytime symptoms.
The obesity hypoventilation syndrome is the most clinically severe form of sleep-disordered breathing and is characterized by chronic alveolar hypoventilation, obesity, daytime hypercapnia (PaCO2 > 45 mm Hg). It frequently becomes manifest with pulmonary hypertension and right heart failure.
American Sleep Disorders Association. The International Classification of Sleep Disorders Diagnosis & Coding Manual. American Academy of Sleep Medicine, 2001. (Lists and explains the various sleep disorders.)
National Commission on Sleep Disorders Research. Wake up America: A National Sleep Alert. Government Printing Office, 1993. (Offers facts and findings regarding sleep deprivation and its effects on citizens.)
- History of habitual snoring, excessive daytime sleepiness, or witnessed apneas.
- Neck size > 17 inches in males or > 15 inches in females and/or body mass index (BMI) > 27 kg/m2.
- Definitive evidence of OSA by polysomnography.
OSA is a disorder characterized by loud, habitual snoring and the repetitive obstruction of the upper airway during sleep, resulting in prolonged intervals of hypoxia and fragmented sleep. As a result, patients with OSA suffer from excessive daytime sleepiness, enuresis, poor work performance, and erectile dysfunction. The long-term sequelae are severe and can include accidents, hypertension, ischemic heart disease, cardiac arrhythmias, and stroke.
Large cohort studies have demonstrated that OSA is common: almost 25% of adult men 20–60 years old and 9% of adult women 20–60 years have an AHI > 5 events/h. It was further found that 4% of adult men and 2% of adult women had OSA syndrome with an AHI > 15 and both daytime and nighttime symptoms. Despite its prevalence, it is estimated that almost 85% of people with OSA remain undiagnosed.
The pathogenesis of OSA is multifactorial, and it is widely accepted that OSA lies somewhere on a continuum of sleep-disordered breathing (Figure 41–1) that begins with snoring and ends with obesity hypoventilation syndrome. Determining what causes a person to be susceptible to the conditions on the continuum is one of the goals of treatment.
The continuum of sleep-disordered breathing. The concept of sleep-disordered breathing is that increasing upper airway resistance (UARS) can cause progressively worsening disease that can manifest with similar as well as new signs and symptoms.
Air moving through the upper airway encounters resistance in transit to the lungs, and in the apneic person, this resistance is increased. This new resistance increases the load on the respiratory musculature, which is required to overcome upper airway resistance with higher negative inspiratory pressures. The negative inspiratory pressure narrows the upper airway in an incremental fashion until, theoretically, the airway collapses. Soft tissue compliance, redundant upper air way mucosa, and pharyngeal dilator muscle tone are all presumed to play an important role. Clinically, this translates to progressive vibration and collapse of the upper aerodigestive soft tissue structures, causing snoring and obstruction of air flow.
The nose and nasal cavity appear to play less crucial roles in the pathogenesis of OSA. Over half of the normal resistance in the upper airway is generated at the internal nasal valve, and obstruction at this point narrows this inlet and increases upper airway resistance. Septal deviation and other causes of nasal obstruction may play a role in the pathogenesis of sleep-disordered breathing, and patients with allergic rhinitis have an increased risk for developing sleep-disordered breathing because of significant turbinate or mucosal swelling. However, these features are not believed to play significant roles in the average patient with OSA.
A number of risk factors for OSA have been identified. Obesity is one of them. A threefold increase in the prevalence of OSA occurs with 1 standard deviation increase in BMI above normal. Results from one study demonstrate a positive correlation between AHI severity and both the BMI and the circumference of a patient's neck. Although men represented 47.2% of the study cohort, 71% of the participants with an AHI > 30 were men, indicating that men disproportionately represent those with OSA.
Although whites and blacks appear to be evenly represented as AHI severity increases, Native Americans appear to be disproportionately represented in groups with higher AHI. In addition to weight, neck circumference, sex, and race, other factors such as genetic syndromes (discussed later) and endocrine factors have also been implicated OSA. Patients with growth hormone abnormalities, specifically acromegaly, may develop OSA as a consequence of changes in craniofacial structure and upper airway collapsibility.
The most common nighttime symptoms of OSA include loud, habitual snoring, apneas, choking or gasping sounds, and nocturia or enuresis. Vibrations in upper airway soft tissues produce the loud, crescendo snoring and signify increased upper airway resistance. Apneas, which frequently terminate abruptly with gasping noises, represent complete upper airway obstruction. The negative inspiratory pressure generated during apneic events is transmurally delivered to the contracting heart and stretches the right atrium. As a consequence, atrial natriuretic peptide is released, leading to nocturia and enuresis in some patients. The repetitive arousals and frequent awakenings to micturate lead to sleep fragmentation, which may lead to daytime symptoms.
Nearly 30% of adult men and 40% of adult women with an AHI > 5 events/h report not feeling refreshed in the morning when arising. In addition, 25% of adult men and 35% of women with an AHI > 5 events/h complain of excessive daytime sleepiness, which can cause frequent napping or dozing, poor work performance, and automobile accidents.
All patients should be evaluated for hypertension since it is correlated with OSA severity. Because studies have shown a positive correlation between OSA and BMI > 27.8 kg/m2 in men and BMI > 27.3 kg/m2 in women as well as neck circumference—measured at the level of the cricothyroid membrane—>17 inches in men and >15 inches in women, weight and neck circumference should be recorded.
The outward appearance of thyromegaly or signs of dry skin, coarse hair, or myxedema may lead to a diagnosis of hypothyroidism, and an inattentive or unkempt patient who seems disengaged or speaks with a sad or flat affect may have undiagnosed depression. Both these conditions can cause excessive sleepiness or fatigue and should be considered before diagnosing OSA.
The patient is always examined in the Frankfurt plane—a line bisecting the inferior orbital rim and the superior rim of the external auditory meatus that is always parallel with the floor. To assess the patient for maxillary retrusion, a line dropped from the nasion to the subnasale should be perpendicular to the Frankfurt plane. To assess the patient for retrognathia, a line bisecting the vermillion border of the lower lip with the pogonion should be perpendicular to the Frankfurt plane as well. If the pogonion is retroposed more than 2 mm, retrognathia is suspected. A lateral cephalometric x-ray helps evaluate this area with precision.
The nose should be examined for signs of gross deformity, tipptosis, asymmetry of the nostrils, and internal valve obstruction. The examiner can perform the modified Cottle maneuver to dilate the nasal valve and assess for improvement in breathing. The nasal cavity should be thoroughly examined for turbinate size, signs of polyps, masses, rhinitis, and purulent discharge. The septum should be examined for signs of defects or deviation. Nasopharyngoscopy permits evaluation of the posterior choanae (to discover the rare case of stenosis or atresia), the eustachian tube orifices, the velopharyngeal valve, and the adenoids, and it can provide direct observation of the velopharynx during the Müller maneuver, which some believe to be helpful in identifying the site of obstruction in OSA.
The tongue should be examined for size and for stigmata of OSA. A normal-sized tongue rests below the occlusal plane, and a tongue that extends above this plane is graded as mildly, moderately, or severely enlarged. Tongue crenations, or ridging, if found, may indicate macroglossia. The relationship between the tongue and the soft palate should also be observed, specifically to determine whether an enlarged tongue obscures vision of the palate, whether the palate itself is low-lying or deviated, or whether the posterior pharyngeal wall is obscured by both. The morphology of the soft palate (ie, thick, webbed, posteriorly located, low, and so on) should also be noted. The uvula is also described as normal, long (>1 cm), thick (>1 cm), or embedded in the soft palate. The tonsils should be described as being surgically absent (0) or by their size (1, 2, 3, or 4+, respectively, indicating a 0–25%, 25–50%, 50–75%, or > 75% lateral narrowing of the oropharynx). The tonsils should also be examined for any asymmetry or any other pathology. A narrow oropharynx, independent of tonsil size, should also be noted. A system of examination and staging of the oral cavity examination has been described termed the Obstructive Sleep Apnea/Hypopnea Syndrome Score (OSAHS Score), which is described below.
The hypopharynx can be evaluated by means of flexible nasopharyngoscopy to assess the base of tongue and the lingual tonsils and to look for masses obstructing the supraglottic, glottic, or subglottic larynx. Obliteration of the vallecula, retrodisplacement of the epiglottis obscuring the larynx, lateral pharyngeal narrowing, and general obstruction by the tongue base may indicate hypopharyngeal collapse during sleep. Any abnormalities in appearance, symmetry, and movement of the vocal cords should be noted. Many perform the Müller maneuver to assess collapse of the retropalatal and retroglossal areas during inspiration against a closed nose and mouth scored as a percentage of closure during the maneuver. Opinions on the clinical usefulness of this maneuver are mixed.
Obstructive Sleep Apnea/Hypopnea Syndrome Score (OSAHS Score)
Although description of the structures as noted above appears useful in determining the site of obstruction in OSA, a more formalized staging system has been created (Table 41–2). This system includes three sections including (a) the standard description of tonsils from 0-4, (b) the oral cavity/tongue (Figure 41–2), and (c) BMI. It has been shown to be useful to predict the probability of success in uvulopalatopharyngoplasty for sleep apnea and can serve as a single score to describe patients with OSA.
Table 41–2. The Friedman Staging System. ||Download (.pdf)
Table 41–2. The Friedman Staging System.
|Stage||Friedman Palate Position||Tonsil Size||Body Mass Index|
|IV||1, 2, 3, 4||0, 1, 2, 3, 4||>40|
Friedman palate position. The Friedman palate position is based on visualization of structures in the mouth with the mouth open widely without protrusion of the tongue. Grade I allows the observer to visualize the entire uvula and tonsils. Grade II allows visualization of the uvula but not the tonsils. Grade III allows visualization of the soft palate but not the uvula. Grade IV allows visualization of the hard palate only.
A host of imaging modalities can play a role in identifying the patient with OSA; however, most of them have limited clinical application, and some remain investigational.
Lateral cephalometric studies and plain film x-rays are useful in evaluating the patient with observable craniofacial abnormalities such as midface hypoplasia or mandibular retrusion. These studies are required for precise evaluation of maxillary retrusion, retrognathia, and micrognathia, and they help in planning Phase I and Phase II surgical procedures (discussed later in this chapter). The studies are inexpensive to perform, and the equipment is widely available. However, as a diagnostic tool for OSA in general, they suffer from several limitations including exposure to radiation, absence of supine imaging, and lack of soft tissue resolution.
Computed Tomography (CT) Scanning and Magnetic Resonance Imaging (MRI)
CT scanning and MRI are also commonly available and have facilitated an increased understanding in the differences between the normal and apneic airways (Figure 41–3). Images obtained with both modalities can be used to recreate three-dimensional models of the upper airway and have been used to evaluate apneic airway dynamics during respiration. Both modalities, however, are significantly more expensive than the previously mentioned modalities and have a number of contraindications. Furthermore, CT and MRI have yet to be proved effective in identifying patients with OSA or reliably characterizing OSA severity.
Comparative axial anatomy. Axial magnetic resonance images acquired at the retropalatal levels in a normal patient (left) and an apneic patient (right) demonstrating (1) increased lateral pharyngeal wall dimensions, (2) decreased retropalatal airway area, and (3) increased lateral pharyngeal fat pads in a representative apneic patient. (Image contributed by Richard J. Schwab, MD, University of Pennsylvania Health System, Philadelphia, PA.)
Subjective tests permit the patient to evaluate his or her drive to sleep. These include the Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire (FOSQ), and the Stanford Sleepiness Scale (SSS). For the ESS, the examinee is asked to rate the likelihood of falling asleep during particular events; in the FOSQ, the examinee is asked to assess the impact of sleepiness on the ability to conduct daily activities; and in the SSS, the examinee is asked to rate how sleepy he or she is at the current moment. The ESS offers the advantage of having correlated with multiple sleep latency testing and with AHI.
Multiple Sleep Latency Testing
The multiple sleep latency test is an objective test that evaluates sleep drive and consists of a series of naps occurring at 2-hour intervals repeated every 2 hours. Patients are encouraged to sleep while their physiologic parameters are monitored. Normal sleep latency is 10–20 minutes; however, patients with excessive daytime sleepiness often have sleep latencies of 5 minutes or less.
The definitive study to evaluate OSA is overnight polysomnography (PSG) because it permits direct monitoring of the patient's brain activity, respiratory patterns, and muscle activity during sleep. The PSG records the duration of sleep and events (snoring, hypopneas, apneas, thoracoabdominal excursion, limb movement, and so on) occurring during sleep. Its clinical utility lies in its ability to diagnose and characterize the severity of OSA. In addition, PSG can differentiate among OSA, central sleep apnea, and some other causes of excessive sleepiness.
Drug-Induced Sleep Endoscopy
This examination consists of examination of the patient during drug-induced sleep in a well-controlled setting, typically with propofol administered as the sedating agent. This examination provides the closest representation yet of dynamic obstruction of a patient during sleep. It has proven itself to be a safe, feasible, and valid assessment of the upper airway, though correlation with specific surgical interventions on identified sites has not been made.
Nearly 20% of all drivers report falling asleep behind the wheel at least once in their lives, and patients with OSA have an increased risk. Patients with an AHI > 40 events/h are more than three times more likely to crash an automobile than are controls, and patients with excessive daytime sleepiness can be as incapacitated as intoxicated (blood alcohol level > 0.1%) volunteers on reaction-timed sequences. Predicting who has an increased risk, however, is difficult. Legal standards and obligations of the physician vary from state to state with regard to the issue of reporting patients at risk or with a history of sleep-related accidents.
Establishing a relationship between OSA and hypertension has been confounded by multiple clinical variables; however, one study has demonstrated that men and women with an AHI > 30 events/h have a 1.5 relative risk and a 1.17 relative risk, respectively, for developing hypertension. When studies control for hypertension, patients with OSA have an increased risk of cardiovascular mortality secondary to myocardial ischemia: patients studied overnight with Holter monitors demonstrate myocardial ischemia that is decreased with continuous positive airway pressure (CPAP) therapy. There is strong evidence for the increased incidence of fatal and nonfatal cardiovascular outcomes in patients with severe OSA who have not been treated when compared with normal volunteers in recent studies. An increased prevalence of sleep-disordered breathing has been found in patients with first-time stroke as early as AHI > 5 events/h, and patients with AHI > 11 events/h have 1.5 times the odds-adjusted risk for stroke.
The most widely deployed treatment for OSA is CPAP, which is the first recommended therapy for patients with OSA. CPAP decreases snoring and apneas and improves symptoms of excessive daytime sleepiness. Moreover, a 3-year study demonstrated that patients with excessive daytime sleepiness who were treated with CPAP significantly decreased their accident rates to levels comparable to normal controls. The American College of Chest Physicians recommends initiating CPAP therapy for all patients with an AHI > 30 events/h and for all patients with an AHI of 5–30 events/h who are symptomatic. Although CPAP is 90–95% effective in eliminating OSA, its continued efficacy relies on patient compliance, with average usage being 4–5 hours/night and 85% compliance at 6 months under the absolute best of circumstances. Despite immediate objective and subjective improvements, no definitive studies establish the duration of regular use necessary to reduce or eliminate long-term sequelae. Patients often complain of claustrophobia, headache, rhinitis, facial or nasal irritation, aerophagia, and inconvenience or social embarrassment while using CPAP, all of which limit its use.
Oral appliances can be used in patients with primary snoring, those with mild-to-moderate OSA, and those refusing CPAP. The more thoroughly tested of the oral appliances are the titratable mandibular repositioning devices. In mild-to-moderate OSA, these devices have been shown to decrease AHI to levels comparable to CPAP therapy, to improve symptoms of excessive daytime sleepiness, and to decrease AHI in some patients unsuccessfully treated with uvulopalatopharyngoplasty. Nightly use of oral appliances is typically tolerated better than CPAP. Patients wearing oral appliances may complain of jaw or temporomandibular joint pain (both of which seem to be lessened by the titratable oral appliances), head aches, and excessive salivation. The long-term effects and outcomes of patients with OSA who use oral appliances are incompletely studied.
Overweight patients should be encouraged to lose weight because moderate reductions in weight have been demonstrated to increase upper airway size and improve upper airway function. Coordination of weight loss with a dietitian may improve outcome and in many cases is necessary (eg, in diabetics and the morbidly obese). Since many patients with OSA are morbidly obese, bariatric surgery has been evaluated as a treatment for weight loss in this population, but it is not recommended for routine weight loss in patients with OSA.
Patients should also be informed to avoid sedatives, alcohol, nicotine, and caffeine in the evening because these substances can influence upper airway muscle tone and central mechanisms.
Positional therapy has been suggested as an adjunctive therapy for patients who have primarily supine-dependent obstructive events, which are easily identified on PSG. Patients are instructed to sleep in the lateral decubitus position rather than the supine position, and a host of techniques have been used to prevent reversion to the supine, such as sewing tennis balls to the backs of shirts and rearranging pillows.
External nasal dilators and ephedra- or ephedrine-based products are also popular treatments for snoring and OSA. Although some have been demonstrated to reduce snoring in patients with chronic rhinitis or nasal obstruction, most of these products have failed to show any consistent benefit in the treatment of primary snoring or OSA. Ephedra-based products are not evaluated by the FDA and are therefore discouraged as treatment.
Surgical treatment of patients with OSA is complex and must be individualized. Surgical treatment is targeted as sites identified in physical examination and the other described examinations to maximize effectiveness and minimize surgical morbidity. A staged approach is typically used that targets the likeliest sites of obstruction with planned retesting and reexamination of patients 4–6 months after surgery to determine the effect of surgical treatment on the OSA patients.
One of the most widely accepted protocols for approaching sleep apnea surgery is based on a series of 306 consecutive surgically treated patients with OSA, by Nelson Powell and Robert Riley. In the Powell–Riley protocol, selecting patients for surgery begins with a thorough physical examination, upper airway endoscopy with the Müller maneuver, cephalometric studies, and overnight PSG. This will be described below as Phase I and Phase II surgery.
Patient treatment is initiated with Phase I surgery: (1) patients with Type I upper airway anatomy (ie, oropharyngeal obstruction) undergo uvulopalatopharyngoplasty (UPPP); (2) patients with Type II upper airway anatomy (ie, oropharyngeal and hypopharyngeal obstruction) undergo UPPP and genioglossus advancement with or without hyoid myotomy; and (3) patients with Type III upper airway anatomy (hypopharyngeal obstruction) undergo genioglossus advancement without palatal surgery. Of note, patients with an AHI > 30 events/h have an increased risk for perioperative airway complications and require overnight observation; they also have a decreased threshold for intubation or a temporary tracheotomy.
All patients undergoing Phase I surgery require general anesthesia and must be informed of potential risks related to anesthesia, postoperative pain, infection, bleeding, and short- and long-term velopharyngeal insufficiency in UPPP patients.
The UPPP procedure entails conservative excision of the inferior margin of the soft palate, including the uvula, as well as excision of redundant mucosa with suture fixation of the pharynx and palate. If the tonsils are present, they are excised. Meta-analysis demonstrates that UPPP significantly reduces AHI, apnea indices, and oxygen desaturations as well as increases REM sleep in postoperative patients. UPPP is effective in eliminating snoring in 90% of selected patients. When “success” is defined as a 50% reduction in AHI, UPPP is 53% successful and has been demonstrated to increase upper airway cross-sectional area and airway volume at the retropalatal level (Figure 41–4). When patients have Type II or Type III upper airway anatomy, as age, BMI, and AHI increase, UPPP becomes less effective.
Pre- and post-UPPP axial anatomy. Axial magnetic resonance images acquired at the same retropalatal level in a patient before and after UPPP. UPPP, uvulopalatopharyngoplasty. (Image contributed by Schwab RJ et al. University of Pennsylvania Health System, Philadelphia, PA.)
Performing genioglossus advancement attempts to correct the retroglossal obstruction that occurs in patients with Type II and Type III upper airway anatomy by placing the geniohyoid muscle and genioglossus muscle under increased tension via a mandibular osteotomy. Genioglossal advancement can be achieved by performing a limited osteotomy (Figure 41–5A) or by creating a rectangular window and sliding the geniohyoid complex anteriorly (Figure 41–5B). The latter procedure may by performed using various sagittal or circular osteotomy devices with custom or prefabricated plating systems. Suspension of the hyoid bone from the mandible has been largely supplanted by approximating the hyoid bone and the thyroid cartilage (Figure 41–6). (Genioglossus advancement, therefore, increases retroglossal airspace by virtue of drawing the genial tubercle and genioglossus complex anteriorly. Typically, patients with an AHI > 30 events/h require genioglossus advancement for treatment because of base of tongue obstruction. Phase I surgery in patients with Type II upper airway anatomy is approximately 60–65% successful (defined as a 50% reduction in AHI or a postoperative AHI equivalent to preoperative AHI while using CPAP). Phase I surgery in patients with Type III upper airway anatomy who undergo genioglossus advancement alone is 66–85% successful. In these two groups (UPPP with genioglossus advancement and genioglossus advancement alone), the nocturnal oxygen desaturation is significantly improved.
Genioglossal advancement. (A) Mortise genioplasty. (B) Block genioplasty.
Hyoid myotomy. Modified myotomy in which the hyoid bone is advanced anteriorly and inferiorly and approximated to the thyroid cartilage.
Patients who do not improve (as evidenced by PSG) by 6 months after Phase I surgery are encouraged to undergo Phase II surgery.
Maxillary-mandibular osteotomy, or advancement of both the maxilla and mandible, is performed in Phase II surgery. Phase II surgery (following Phase I surgery) is 97–100% successful in reducing AHI and in improving blood-oxygen desaturation, as well as increasing Stages III, IV, and REM sleep. For patients adhering to the Phase I and II protocol, the overall success rate is approximately 95% (observed over a 1- to 4-year follow-up period). However, the overall success rate, which includes those dropping out of the protocol, is 77% (observed over an average of 9 months of follow-up).
Laser-Assisted Uvuloplasty (LAUP)
LAUP is similar to UPPP in that the inferior margin of the soft palate and the uvula are excised. However, LAUP differs from UPPP in that it uses a laser (CO2, argon, KTP) rather than a knife, is performed with topical and local anesthesia, is not designed to address the tonsils or pharyngeal narrowing, and is performed in 1–3 office sessions. If there is evidence of obstructing tonsils or redundant pharyngeal mucosa, LAUP should not be offered. In addition, LAUP is not typically used in patients with an AHI > 30 events/h. Results of LAUP in selected populations are variable, and the procedure is approximately 50% effective for OSA and 80–90% effective for snoring with fewer complications and less morbidity for patients than UPPP. Side effects of LAUP include moderate pain, bleeding, risk of velopharyngeal insufficiency, and infection.
Radiofrequency ablation of the palate is also a relatively new procedure that can be used to treat patients with primary snoring or an AHI < 15 events/h who have predominantly palatal obstruction. Radiofrequency ablation delivers approximately 500 J to target tissues causing coagulative necrosis, scarring, and eventually tissue contraction. Initial reports suggest that radiofrequency ablation is approximately 75% effective in eliminating snoring, and despite improvement in ESS scores, it does not change AHI. Radiofrequency ablation of the tongue and tongue base may also be used. Risks of radiofrequency ablation include pain, bleeding, velopharyngeal insufficiency, palatal fistula, and infection.
Treatment of tongue base obstruction is a challenging area of surgery for sleep apnea. Procedures initially used for tongue reduction included use of tracheotomy and demonstrated significant morbidity and pain. Because of this, they never gained widespread acceptance by physicians or patients. More recently, less invasive procedures to treat tongue base obstruction have been developed that have reduced morbidity significantly and have gained some acceptance in the algorithm for treatment.
Tongue base reduction has been performed utilizing cold ablation therapy, thus reducing tissue necrosis, edema, and pain. Midline laser glossectomy as well as submucosal open glossectomy have also been used with decreased morbidity. Studies evaluating the efficacy of transoral robotic tongue base resection are presently being performed.
Procedures that suspend the hyoid bone or tongue base though suture stabilization have been used to treat hypopharyngeal obstruction. Advancement and suture fixation of the hyoid bone to the thyroid cartilage appears to open the hypopharyngeal airway, though effectiveness has been difficult to demonstrate in the published literature. Similarly, suture suspension of the tongue base and hyoid bone has been used with some effectiveness, though technical challenges remain to provide a consistent and reliable method that will gain acceptance among practitioners and patients.
The final and gold standard surgical treatment for OSA is tracheostomy, which bypasses the upper airway obstruction completely. Tracheostomy is indicated in patients with corpulmonale, obesity hypoventilation syndrome, nighttime arrhythmias or disabling excessive daytime sleepiness who refuse CPAP and surgical intervention or in those who have failed previous surgical interventions. Tracheostomy is highly successful in eliminating excessive daytime sleepiness, improving AHI to normal levels, and normalizing sleep architecture. However, it is not 100% effective in eliminating symptoms and sequelae in all patients, and it is associated with complications such as dysphagia, plugging, tracheal stenosis, and granuloma formation. Decannulation and reversal of tracheostomy usually are uncomplicated and result in the return of symptoms.
The placement of soft palate implants has been approved for use in snoring and in mild-to-moderate OSA. When inclusion criteria are met for this procedure, approximately 63.9% of patients experience a reduction in AHI to < 10 events/h, though treatment effect is small. Complications such as implant extrusion and worsening of symptoms have been reported. Practitioners typically utilize this method for simple snoring, where proper patient selection can achieve acceptable results.
All patients should be reexamined by repeat PSG 4–6 months after surgery. Continued postoperative follow-up permits the evaluation of subjective and objective improvement as well as the opportunity to address additional sites of obstruction as necessary.
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(Description of the staging system with clinical outcomes.)
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Nieto FJ et al. Association of sleep-disordered breathing, sleep apnea, and hypertension in a large community-based study. Sleep Heart Health Study. JAMA
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Peker Y et al. Respiratory disturbance index: An independent predictor of mortality in coronary artery disease. Am J Respir Crit Care Med
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. (A review of 306 patients with obstructive sleep apnea undergoing Phase I and Phase II surgery protocol.)
Schwab RJ et al. Upper airway assessment: Radiographic and other imaging techniques. Otolaryngol Clin North Am
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Sher AE et al. The efficacy of surgical modifications of the upper airway in adults with obstructive sleep apnea syndrome. Sleep
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Wright J et al. The efficacy of nasal continuous positive airway pressure in the treatment of obstructive sleep apnea syndrome is not proven. Am J Respir Crit Care Med
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Yaggi HK et al. Obstructive sleep apnea as a risk factor for stroke and death. N Engl J Med
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Young T et al. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med
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