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Obstructive Sleep Apnea. Obstructive sleep apnea (OSA) is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe Occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway.
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1. Obstructive Sleep Apnea Bruce Tasios, DDS
Department of Orthodontics
UMDNJ
3. Obstructive Sleep Apnea Leads to partial reductions and complete pauses in breathing that last at least 10 seconds during sleep
Most pauses last between 10 and 30 seconds, but some may persist for one minute or longer
Can lead to abrupt reductions in blood oxygen saturation, with oxygen levels falling as much as 40 percent or more in severe cases
Brain responds to the lack of oxygen by alerting the body, causing a brief arousal from sleep that restores normal breathing
4. Obstructive Sleep Apnea This pattern can occur hundreds of times in one night, resulting in a fragmented quality of sleep that often produces an excessive level of daytime sleepiness
Most people with OSA snore loudly and frequently, with periods of silence when airflow is reduced or blocked
They then make choking, snorting or gasping sounds when their airway reopens
5. Prevalence Can occur in any age group, but prevalence increases between middle and older age
In the United States, 8% of men and 2% of women are affected by OSA
OSA occurs in about 2% of children and is most common at preschool ages
Estimated that 80-90% of adults with OSA remain undiagnosed
Average untreated sleep apnea patient’s health care costs are estimated to be $1336 more than an individual without sleep apnea
6. Significant Health Issue Complications secondary to nocturnal hypoxia and hypercapnia
Systemic and pulmonary hypertension
Congestive heart failure
Ischemic heart disease
Myocardial infarction
Cardiac arrhythmias
Neurological complications
Diabetes
Motor vehicle accidents
Life-threatening problem: untreated moderate to severe OSA has a mortality rate of 37% during a period of 8 years
7. Symptoms Affected individuals are rarely aware of having difficulty breathing during sleep, even upon wakening
Often recognized by others witnessing the individual during episodes or suspected because of its effects on the body
8. Etiology General
Obesity/elevated BMI
Nasal Cavity/Nasopharynx
Deviated nasal septum
Turbinate hypertrophy
Nasal polyps
Nasal tumors
Sinusitis
Enlarged adenoids
9. Etiology Oral Cavity/Oropharynx
Macroglossia
Enlarged palatine tonsils
Enlarged uvula
Retroglossal/laryngopharynx
Enlarged lingual tonsils
Laryngeal abnormalities/masses
10. Etiology Skeletal
Maxillary hypoplasia
Mandibular hypoplasia
11. Diagnosis Does the patient have sleep apnea?
If a diagnosis of sleep apnea is made, should differentiate between obstructive and central sleep apnea
Central sleep apnea
Breathing is interrupted by a lack of respiratory effort
Pathophysiology is related to abnormalities of central control mechanisms and chemoreceptor function rather than to airway obstruction
Impervious to treatment modalities used in obstructive sleep apnea, which are aimed towards creating more space in the breathing airway
12. Diagnosis How severe is the patient’s sleep apnea?
Does the patient have any health issues secondary to OSA?
What is causing the patient to suffer from OSA?
13. Diagnosis Accurate medical history
History of respiratory disease
May contribute to causing respiratory problems during sleep
History of cardiovascular disease and diabetes
Possible indication of severity of OSA
Epworth Sleepiness Questionnaire
Indication of daytime sleepiness
Detailed information from patient’s partner
14. Physical Examination Obesity/Body mass index
Neck circumference
Greater than 17 inches is highly correlated with OSA
Soft tissue profile
Nasal examination
Oral examination
Mallampati classification
Used to evaluate the oropharyngeal tissues and the potential for airway obstruction
Commonly used as an indicator for difficulty of intubation
15. Mallampati Classification
16. Airway Analysis Upper airway imaging is a powerful technique to determine the mechanism underlying the pathophysiology of OSA
Imaging Modalities
Nasopharyngoscopy
Cephalometrics
Cone-Beam Computed Tomography
Computed Tomography (CT)
Magnetic Resonance Imaging (MRI)
17. Endoscopic Pharyngoscopy Used to detect anatomical abnormalities in the upper airway, from the nasal passages to the glottis
Sleeping fiberoptic endoscopy
Endoscope is present while patient is sleeping
Effective method to locate the obstruction site
Procedure may cause sleep disturbances and is often refused by patients
18. Endoscopic Pharyngoscopy Mueller’s Maneuver
Diagnostic technique to determine the collapsibility of the tissue surrounding the airway
Executed by requesting the patient to inhale while the mouth and nose are occluded with a fiberoptic nasopharyngoscope in place
The resulting negative pressure may cause the walls of the upper airway to collapse in a narrowed airway
Maneuver has been shown to correlate to OSA severity
19. Cephalometrics Lateral cephalogram presents the profile view of the viscerocranium
Common abnormalities found in OSA patients: retrognathic maxilla and mandible, short mandibular length, long anterior face height, clockwise rotation of the facial structure, and short cranial base
Useful for measuring airway changes in a patient before and after treatment
20. 3-D Imaging Cone-Beam Computed Tomography
Computed Tomography
Magnetic Resonance Imaging
Evaluate the upper airway 3-dimensionally
Provide extremely accurate measurements of the airway in all dimensions
21. Polysomnography Commonly used to determine presence and severity of OSA
EOG: electro-oculogram
REM vs. NREM
EEG: electroencephalogram
Each sleep stage is associated with a specific wave pattern
Arousal
EMG: electromyogram
Monitor muscle tone
ECG: electrocardiogram
Detect cardiac abnormalities
Oronasal airflow
Thoracic and abdominal respiratory effort
Differentiate between central vs. obstructive
Pulse oximetry
Monitor arterial oxygen saturation
22. Apnea-Hypopnea Index Apnea-Hypopnea Index (AHI)
The number of apneas and hypopneas per hour of sleep
Apnea
Cessation of airflow for more than 10 seconds
Hypopnea
Decrease in airflow by 50% with significant oxygen desaturation
Also known as the Respiratory Distress Index (RDI)
23. Non-surgical Treatment Options Weight loss
Positional treatment
Medication
Continuous positive airway pressure (CPAP)
Palatal Expansion
Oral appliances
24. Weight Loss Many patients who suffer from OSA are overweight
Excess weight contributes to upper airway obstruction through an increase in pharyngeal mass, narrowing of the upper airway, and increased work of breathing and oxygen demand
Weight loss via dieting and exercising has beneficial effects on the clinical status of OSA in overweight patients
25. Weight Loss However, it may be hard to lose weight when you have OSA, as you may be too tired to exercise and you may eat to stay awake
Previous studies have shown that obese patients with OSA are not successful at losing weight when properly counseled and prescribed a weight loss regimen
Liposuction may be considered
26. Positional Treatment Sleeping in the supine position tends to promote OSA, as gravity makes it more likely for the tongue to fall back and block the airway
Treatment:
Raise height of bed
Avoid supine position
27. Medications Chemoreceptors detect changes in carbon dioxide, oxygen, and pH in arterial blood
Increase in carbon dioxide and decrease in oxygen and pH send signals to the brainstem, calling for an increase in respiration
Medications used to treat OSA take advantage of this feedback mechanism
Acetazolamide: lowers blood pH to encourage respiration
Avoid alcohol and other CNS depressants that may potentially relax the airway
28. Continuous Positive Airway Pressure (CPAP) Continuous Positive Airway Pressure pneumatically splints open the patient’s airway during sleep by delivering pressurized air into the throat
Effective at eliminating apneas and hypopneas
Considered the gold standard in the treatment of OSA
29. CPAP Side Effects 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 (~50%)
Side effects:
Oronasal dryness
Conjuctivitis from air leak
Noise
Claustrophobia
Mask discomfort
Skin abrasions/rash
30. Palatal Expansion OSA patients may have considerable skeletal maxillary constriction, resulting in upper airway narrowing and increased nasal resistance
Consequent mouth breathing results in a low tongue posture, provoking a flattening of the retroglossal airway space
Growing patients who suffer from OSA with maxillary constriction may benefit from rapid palatal expansion (RPE)
31. Palatal Expansion RPE treatment widens the maxillary bone via distraction osteogenesis at the midpalatal suture
Increases the volumetric space of the nasal cavity, which helps reduce nasal resistance
Promotes spontaneous repositioning of the tongue to a normal position
32. Palatal Expansion Rapid palatal expansion is successful at treating children with OSA
Reduced symptoms of OSA in 71.4% of children
Significantly decreased AHI in 78.5 % of children
Converted 92.8% of oral breathers to nasal breathers
Positive results of RPE treatment has increased the use of surgically assisted rapid palatal expansion in adult patients
Successful in adult patients with a transverse deficiency
May be coupled with mandibular symphyseal distraction osteogenesis to permit greater transverse expansion without loss of proper occlusal contacts
33. Oral Appliance Therapy Oral appliances used to treat OSA function to increase the size of the upper airway by advancing the mandible, protruding the tongue, and possibly elevating the soft palate
Mandibular advancement results in anterior displacement of the soft palate, genioglossus, and suprahyoid muscles
Increases the dimensions of the hypopharynx, oropharynx, and velopharyngeal areas
Mandibular displacement also stretches the palatoglossal and palatopharyngeal arches
Increases upper airway muscle activity, making the airway less likely to collapse
34. Oral Appliance Therapy There are no strict guidelines in the design of oral appliances for OSA management and there is a plethora of them in use
There are 1-piece or 2-piece appliances made from soft elastomeric material or hard acrylic
2-piece appliances have the advantage of allowing for titratable mandibular advancement
35. Appliance Design Patients find appliances that encroach the tongue space and open the bite uncomfortable
No differences in efficacy between greater or lesser mandibular opening in reducing AHI
No difference in treatment success between 1-piece and 2-piece appliances
36. Important Considerations Four factors that influence treatment success of Oral Appliance Therapy
Mild to moderate OSA severity (AHI <30)
Less effective at treating patients with severe OSA
14-61% of severe OSA cases compared with 57-81% of patients with mild to moderate OSA were successfully treated (AHI<5)
Low BMI
Obese patients are more resistant to oral appliance therapy
37. Important Considerations Large Mandibular Advancement
Many clinicians recommend starting with a mandibular position corresponding to 75% of maximum mandibular protrusion, as this is the most comfortable position
Direct relationship between the degree of mandibular advancement and reduction in AHI
Supine AHI
Patients who have greater supine than lateral AHI readings demonstrate better outcomes with oral appliance use
38. Adverse Effects Transient pain in the upper and lower incisors on wakening
Excessive salivation
Gingival soreness
TMJ discomfort and noises
Occlusal changes
Reduction of overbite and overjet
Retroclination of maxillary incisors (1.9°) and proclination of mandibular incisors (2.8°)
Skeletal changes
Mandible is relocated downwards and forwards
Increase in lower face height
39. Surgical Treatment Options Septoplasty
Turbinoplasty
Partial turbinectomy
Polypectomy
Excision of nasal tumours
Adenoid tonsils excision
Uvulopalatopharyngoplasty
Tonsillectomy
Uvulectomy Partial glossectomy/tongue base reduction
Genioglossal advancement
Lingual tonsils excision
Hyoid advancement/suspension
Maxillomandibular advancement
Excision of laryngeal tumours
Tracheotomy
40. Risks of Surgical Treatment Surgery in the upper airway results in postoperative edema, which has acute adverse effects on breathing
Several medications used during surgery are respiratory depressants and can remain in the body in low amounts for hours/days
OSA can be dangerously aggravated by these drugs thus these patients need prolonged monitoring following surgery
There is also a concern with postoperative analgesics that are respiratory depressants
Other complications: nerve damage, excessive bleeding
41. Which Surgical Treatment Option? When an obvious anatomical abnormality is detected, the appropriate surgical procedure is performed accordingly
Unfortunately, even with sound imaging modalities, it is still difficult to ascertain the pathophysiology of OSA
It is often a combination of multiple sites affecting the upper airway that contribute to OSA
42. Which Surgical Treatment Option? Retropalatal and retroglossal openings are common areas that are obstructed in the upper airway
Maxillomandibular advancement has been shown to be very successful at treating OSA with retropalatal and retroglossal obstructions
However, some believe that maxillomandibular advancement is too invasive and should only be performed following a poor response to a procedure involving uvulopalatopharygoplasty, genioglossal advancement, and hyoid suspension
These clinicians argue that it would be overly aggressive to submit a patient who would have responded to a less invasive surgery to the risks/complications from maxillomandibular advancement
43. What is Successful Treatment? In surgical studies, the definition of success is mainly based on objective measures
Common objective parameters are the apnea-hypopnea index and lowest oxygen saturation
Current accepted definition for surgical cure:
AHI less than 20 with a reduction greater than 50%
Few desaturations less than 90%
Reason for setting the success less than 20 is that several studies have found that an index >20 translates to increased morbidity and mortality
44. Genioglossus Advancement Rectangular osteotomy at the chin which contains the genial tubercles
Chin is fixated in a more anterior position
Technique increase posterior airway space by anteriorly repositioning the genioglossus, geniohyoid, and digastric muscles
45. Uvulopalatopharyngoplasty Strives to increase the dimension of the upper airway by removing tissue in the throat
Involved tissues may or may not include the uvula, soft palate, palatine tonsils, adenoids, and pharynx
Risk for velopharyngeal insufficiency
Results in lack of palatal closure, allowing air to escape during speech and swallowing
46. Hyoid Suspension Hyoid bone is important in determining the position of the tongue
Anterior advancement of the hyoid bone may enlarge the airway at the tongue base level
Surgical procedure involves repositioning the hyoid bone anteriorly and inferiorly and suturing it to the thyroid cartilage
Beneficial effects related to stabilizing the soft tissue, preventing airway collapse, rather than to simple changes in airway diameter
47. Success Rate The success rate of stage 1 surgery involving uvulopalatopharyngoplasty, genioglossal advancement, and hyoid suspension at treating OSA is 60%
The success rate of stage 2 surgery involving maxillomandibular advancement at treating OSA is 95%
Previous studies have shown that only 25% of stage 1 non-responders went on to stage 2 surgery
For this reason, other clinicians recommend using the most efficacious technique from the start and proceeding directly with maxillomandibular advancement
48. Prerequisites for MMA Patient’s AHI must be greater than 15, with a lowest desaturation below 90% and subjective daytime sleepiness
Conservative treatments such as weight loss, mandibular repositioning devices, and/or continuous positive airway pressure must have been unsuccessful or intolerable for the patient
Upper airway is obstructed at multiple sites or obstruction could not be distinguished, as it was diffuse
Patient should present with a dentofacial skeletal deformity, most often a class II relationship
49. MMA Rationale Retro-positioning of the jaws causes the structures that form the anterior and lateral boundaries of the posterior airway such as the tongue, palate, and pharyngeal tissues to be displaced posteriorly
The tissues become lax and more liable to collapse in the presence of negative pressure
This results in constriction of the posterior airway, increased airway resistance, and obstructions
50. Maxillomandibular Advancement Advancement of the mandible pulls the geniohyoid, genioglossus, mylohyoid, and the digastric muscles anteriorly
This brings the base of tongue and hyoid bone forwards and upwards
Also creates a larger volume for the tongue and floor of mouth
These two effects result in the enlargement of the posterior airway space at the retroglossal and hypopharyngeal region level
Technique: Le Fort I level maxillary osteotomy and bilateral sagittal split mandibular osteotomy
51. Maxillomandibular Advancement
52. Preoperative Orthodontics Ideally, pre-surgical orthodontic treatment should be used to ensure a good postoperative occlusion and to correct any pre-existing malalignment of teeth
Primary goal would be to maximize the amount of maxillary and mandibular advancement while maintaining a reasonable occlusion
For example, in class II patients it is advisable to retract the mandibular incisors and procline the maxillary incisors to maximize the amount of mandibular advancement
However, many OSA patients are older and are unwilling to undergo the recommended orthodontic treatment
53. Preoperative Orthodontics Equal maxillary and mandibular advancement is performed in patients who do not undergo preoperative orthodontic treatment
However, in those who do receive preoperative orthodontic treatment, the maxilla and mandible may not be advanced in equal amounts, particularly when they do not have a class I occlusion
54. MMA Stability Generally accepted magnitude of advancement was 10mm
Large horizontal advancement of the maxilla and mandible is stable without significant relapse
Strong evidence in the long-term efficacy of MMA, as previous studies have shown that a 90% success rate was maintained after 4 years
55.
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Yow M. 2009. An Overview of Oral Appliances and Managing the Airway in Obstructive Sleep Apnea. Seminars in Orthodontics; 15(2): 88-93.