Surgical Procedures for the Treatment of Obstructive Sleep Apnea Kok Weng Lye and Joseph R. Deatherage Obstructive sleep apnea (OSA) syndrome is a serious health problem that affects a large number of individuals. Research in the field has improved our understanding of the disease, and a holistic management of the OSA patient is becoming widely adopted. When continuous positive airway pressure (CPAP) and dental appliance have failed, surgical procedures to improve the posterior airway are performed. When chosen correctly, these procedures have tremendous benefit to the airway and can potentially cure this devastating syndrome. (Semin Orthod 2009;15:94-98.) © 2009 Elsevier Inc. All rights reserved.
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pnea” is the Greek word for “without breath.” Obstructive sleep apnea (OSA) was first described by Charles Dickens in 1837.1 He coined the term “Pickwickian syndrome” but described a similar presentation of a typical OSA patient; obese, somnolent, and with an excessive appetite. It was only in 1956 that Sidney Burwell carefully documented a case of an OSA patient, rationalized the signs and symptoms, and made a distinction between this disease and other illnesses.2 Since then, there has been a plethora of information on OSA, and it is now recognized as a separate entity. The prevalence of the disease has been found to be 8% in men and 2% of women in the United States.3 This chronic condition has wide ranging effects, from health problems to serious social and financial consequences. The collapse and blockage of the airway leads to snoring, multiple arousals, sleep fragmentation, hypoxia, and reperfusion injuries. The snoring is a result of the vibration of the tissues of the posterior airway caused by the narrowing of the airway and air turbulence. The re-
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Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore. Department of Oral and Maxillofacial Surgery, University of Alabama School of Dentistry, Birmingham, AL. Address correspondence to Kok Weng Lye, Department of Oral and Maxillofacial Surgery, National Dental Centre, 5 Second Hospital Avenue, Singapore, 168938. Phone: 65-6324 8890; E-mail: kokwenglye@yahoo.com © 2009 Elsevier Inc. All rights reserved. 1073-8746/09/1502-0$30.00/0 doi:10.1053/j.sodo.2009.01.003
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duced airflow causes hypoxia and hypercapnia which lead to arousals and sleep fragmentation. This chain of events results in excessive daytime sleepiness (EDS) in 90% of OSA patients.4 In turn, EDS affects concentration, cognition, and ability to work effectively5 and may lead to traffic accidents.6 EDS is a complex state of sleepiness during the daytime hours that is pathological. Physiologically, OSA may bring about arrhythmias, heart failure, ischemic heart disease, systemic and pulmonary hypertension, and neurological complications because of the nocturnal hypoxia, hypercapnia, and reperfusion injury.7-9 In fact, it is a potential life-threatening problem10 and, if left untreated, has a mortality rate of 37% in moderate-to-severe OSA during a period of 8 years.11
Diagnosis The diagnosis of OSA is made from a detailed physiological examination during sleep called polysomnography. This is the required objective investigation for the confirmation of the presence and severity of the condition. It is also able to pick up other sleep disorders like narcolepsy, periodic limb movement disorder and central sleep apnea. The various parameters calculate the amount of apneas (cessation of airflow for more than 10 s), hypopnea (decrease in airflow by ⬎50% with significant oxygen desaturation), amount of oxygen desaturation, and the quality of sleep (amount of REM, stage 3 and stage 4 sleep).
Seminars in Orthodontics, Vol 15, No 2 (June), 2009: pp 94-98
Surgical Procedures for the Treatment of Obstructive Sleep Apnea
To have a comprehensive view of the entire patient, a thorough evaluation also should be done, including an accurate medical history, physical examination, airway analysis, and other additional aids to identify the sites of obstruction in the airway. Some medical conditions, such as chronic obstructive pulmonary disease, restrictive lung diseases, muscular dystrophy, cardiac dysfunction, kyphoscoliosis, hypothyroidism, and pituitary tumors, can impact the diagnosis and treatment of OSA.12 The physical examination includes the weight and body mass index (BMI) of the patient. A neck circumference ⏎43.2 cm is also a positive risk factor for OSA.13 The clinical examination of the airway starts at the nasal aperture. Any nasal septal deviation, internal or external valve collapse, turbinate hypertrophy, nasal polyps, chronic sinusitis, and masses can contribute to reduced nasal airway, which leads to increased negative inspiratory pressure and bring about collapse in the posterior airway.14 The nasopharynx, oral pharynx, and hypopharynx are examined with the aid of a flexible endoscope. The presence and size of any adenoid hypertrophy in the nasopharynx may be of significance and is noted. This is especially so in young patients. The focus of interest is in the retropalatal and retroglossal openings. The retropalatal opening, which is formed by the soft palate and the lateral and retropharyngeal walls, is examined during normal breathing. Its shape and any constrictions in the anteroposterior or lateral dimensions are noted. A Muller’s maneuver is also performed to ascertain the collapsibility of the surrounding tissue.15 This is executed by requesting the patient to inhale while the mouth and nose is occluded, causing a negative pressure in the airway. This maneuver has been shown to correlate to the OSA severity.16 The retroglossal opening is the airway at the tongue base level. The dimension at this level is ascertained to judge the contribution of any macroglossia or retro positioning of the tongue and mandible towards the OSA.17 The patient also can protrude their mandible at this instant, duplicating mandibular advancement, to assess the improvement of the airway. The presence of enlarged lingual tonsils is also a contributory factor as it may be displacing the epiglottis posteriorly against the retropharyngeal wall. The hypopharynx is checked for any restrictions sec-
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ondary to growths, laryngeal changes and vocal cords abnormalities. The oral examination should focus on the length of the soft palate, the size of the palatine tonsils, and the width of the palatal vault and dental arches. In addition, the association of the structures can be determined by the use of some available scales like the Mallampati. The Mallampati scale is used to evaluate the oropharyngeal soft tissues and the potential for airway obstruction. The Friedman score has been developed to assess the relationship between tongue position, tonsil size, and body mass index and the likely success of soft tissue surgical procedures.18 Fujita et al19 simply categorized the upper airway obstruction as either retropalatal or retroglossal. The retropalatal level involves the soft palate, uvula, and palatine tonsils. The retroglossal level involves the tongue base and supraglottic structures. Type I obstruction is the presence of restriction only at the retropalatal level. Type II obstruction is the presence of restriction only at the retroglossal level. Type III is the presence of both obstructions at both levels. However, there is increasing support in a different concept proposed by Moore.20 Moore considered the airway obstruction as a spectrum of disease, starting from primary snoring as the mildest form, to upper airway resistance syndrome (UARS) and then to the different degrees of OSA; mild, moderate, and severe.
Treatment Since Colin Sullivan showed in 1981 that continuous positive airway pressure (CPAP) could pneumatically splint open the collapsed airway and eliminate apneas and hypopneas, the CPAP has been the gold standard in the treatment of OSA.21 There are only minimal side effects with this mode of treatment.22 However, despite its high efficacy, patients frequently cannot tolerate its usage every night for life and thus long-term acceptance has been found to be low.23,24 This has been consistent even with advancement in mask and air pressure delivery system technology.25 The dental fraternity fabricated the mandibular advancement devices (MAD) for these patients as another form of noninvasive therapy. A review of the literature showed that these MADs are more acceptable than CPAP and have reasonable success rates when used in mild-to-mod-
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Table 1. Surgical Procedures for Treatment of OSA-Related Obstructive Problems Region of Interest Nose
Nasopharynx Oroparynx and soft palate
Tongue
Maxillofacial/hard tissue surgery Larynx
Procedure
Problem
Batten graft Spreader graft Septoplasty Turbinoplasty/partial turbinectomy Polypectomy Functional endoscopic sinus surgery Excision/resection Adenotonsillectomy (T&A) Palatal implants (pillar) Radiofrequency volume reduction of palate (RFQ) Cautery-assisted palatal stiffening operation Conservative uvulopalatopharyngoplasty (UPPP) Radical UPPP Laser-assisted uvulopalatoplasty Uvulopalatal flap Transpalatal advancement pharyngoplasty RFQ tonsils Tonsillectomy Injection somnoplasty Uvulectomy Partial glossectomy/tongue base reduction RFQ tongue Endoscopic microdebridement of tongue base Genioglossus advancement Lingual tonsils excision Hyoid advancement/suspension Maxillomandibular advancement (MMA) Mandibular/midfacial distraction osteogenesis (DOG) Epiglottidectomy Excision/resection of laryngeal tumors Laryngoplasty for other malformations
External valve collapse Internal valve collapse Deviated nasal septum Turbinate hypertrophy Nasal polyps Sinusitis Nasal tumors Enlarged adenoids and palatine tonsils Normal palatal length Normal palatal length Retropalatal obstruction with increased palatal length and lax tissue
erate OSA.26 However, the long compliance rates are still not good and there are complications associated with long term usage of the MADs, such as temporo-mandibular joint problems and changes in the occlusion.26 When the nonsurgical therapies for OSA fail or are unacceptable to the patients, surgical options are considered. The first surgical treatment for OSA was tracheotomy in 1969 by Kuhol.27 Previously, in 1964, Ikematsu started treating snoring with a soft palate procedure known as uvulopalatopharyngoplasty (UPPP).28 Building on that, Fujita published results on UPPP in OSA.29 However, Sher’s review in 1996 showed the success rate to be close to 40%.30 Since then, a whole host of procedures were developed to treat OSA. They are all designed to improve the posterior airway from the nasal aperture to the larynx. The procedures are shown in Table 1. Table 2 shows a brief summary of the long-term success rates for common surgical procedures.31 Most of the soft-tissue procedures only augment one part of the posterior airway and thus
Enlarged tonsils Enlarged tonsils Normal palatal length Enlarged uvula Macroglossia Macroglossia Macroglossia Retroglossal obstruction Enlarged tonsils Hypopharyngeal obstruction Multilevel obstruction Severe deformity Laryngeal abnormalities
were limited in their success rate when used individually. Derived from Moore’s concept,20 two principles of therapy were developed.32 The first principle states that the entire upper airway is affected, especially in moderate and severe OSA. The second principle states that the more severe the disorder, the more aggressive the surgical therapy has to be to achieve success. Modern surgical reasoning suggests that severe OSA affects the entire airway and that multilevel pro-
Table 2. Long-Term Results of Surgery to Treat OSA Procedure
Success Rate
Tracheotomy Maxillomandibular advancement Adenotomy and/or tonsillectomy in children Tonsillectomy in adults Laser-assisted uvulopalatoplasty UPPP selected Surgery of the tongue base UPPP unselected Nasal surgery
98% ⬎90% 85–95% Up to 89% 49.2–59.2% 52.3% 25–77% 40.7% ⬍20%
Surgical Procedures for the Treatment of Obstructive Sleep Apnea
cedures are necessary to achieve good results. However, even multilevel surgeries limited to the soft tissue achieved a success rate of 60% or less. Riley et al33 found the success rate for UPPP, genioglossus advancement (GGA), and hyoid suspension (HS) to be 61%33 and Friedman, et al34 achieved a 41% success for UPPP and radiofrequency volume reduction procedure (RFQ). Using the uvulopalatal flap with RFQ, Verse et al35 obtained a success rate of 51%. Hard tissue surgical procedures have shown better success rates but they require more preparation and may have higher morbidity. Maxillomandibular advancement (MMA) which is modeled after conventional orthognathic surgery has achieved remarkable success rates of 97%36 and 100%.37 Therefore, it is important to examine the patients carefully before deciding on the most appropriate surgical procedures.
Defining Surgical Cure/Success There are many parameters that can serve as objective or subjective measures for OSA. Because the diagnosis criteria of OSA are based on the indexes that reflect disturbance in sleep, the same parameters are used to determine improvement or surgical success. The common objective parameters are the respiratory distress index, apnea-hypopnea index, apnea index, and lowest oxygen saturation. The patients’ perception, the Epworth sleepiness score, and the OSA specific quality-oflife instruments are the subjective measures that are used to verify the severity of the condition and determine the efficacy of treatment. In surgical studies, the definitions of success are based mainly on objective measures. In 1981, Fujita et al29 stated that success is achieved if there is a 50% reduction in the postoperative apnea index. Waite et al38 set their success level at a final RDI less than 10 and no desaturations of less than 90%. Powell et al33 considered the operation to be a success if the postoperative RDI was ⬍20, in addition to a 50% reduction in the RDI and normal oxygen saturation. The reason for setting the success to be less than 20 is the fact that several studies have found that an index of greater than 20 translate to increased morbidity and mortality.39 Currently, the commonly accepted definition for surgical cure is respiratory distress index or apnea-hypopnea index less than 20 with a reduction greater than
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50% and few desaturations less than 90% with improvement of subjective symptoms.
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