Popular posts 7: Part 2 of a brilliant summary of orthodontics and Obstructive Sleep Apnea
This is the seventh popular post from my blog. It is a follow-up to last week’s post on the AAO winter meeting on Obstructive Sleeo Apnea. This is about the diagnosis and treatment of OSA by orthodontists. It is very relevant to our clinical practice.
How Is Obstructive Sleep Apnea Diagnosed?
A formal laboratory sleep study called polysomnography (PSG) is the only way to diagnose Obstructive Sleep Apnea. Although home study kits and smartphone apps are available and gaining popularity, it was the consensus of the experts who spoke that none of them has all of the necessary features to provide an accurate diagnosis (i.e. none currently measure brainwaves).
Importantly, orthodontists cannot order, nor are they qualified to interpret, the results of a PSG. The current standard for measuring the severity of OSA is the Apnea-Hypopnea Index (AHI) which represents the number of sleep disturbance “events” per hour. Less than 5 is normal for adults, 5 to 15 is mild, 15 to 30 is moderate, and over 30 is considered severe. For children, less than 1 is normal (in other words, children should have no apnea or hypopnea events during sleep).
Can Obstructive Sleep Apnea Be Diagnosed In Radiographs?
We can construct Interesting and instructive 3D images from CBCT scans and produce measurements like Minimum Cross-sectional Area (MCA). Although some papers report correlations between MCA values and the “risk of Obstructive Sleep Apnea.” We cannot diagnose OSA from radiographs. Only a formal sleep study provides a definitive diagnosis.
Tonsils and adenoids seen in lateral cephalograms may be a factor in pediatric OSA, but again their presence alone does not yield a diagnosis. ENT’s confirm airway obstruction using endoscopy, not radiographs.
Because OSA is not merely a structural problem, the identification of “predisposing morphologies” can be misleading. Many patients who have these predisposing morphologies do not suffer from OSA. Conversely, other patients who have absolutely “normal” appearing anatomy may suffer from it.
“2D and 3D images do not provide a proper risk assessment technique or screening method.”
What Treatments Actually Help Treat OSA In Adults?
The “gold standard” for treating adult sleep apnea is continuous positive air pressure (CPAP). CPAP has a success rate of over 90%. For patients who cannot wear a CPAP, oral appliance therapy (OAT) is 65% successful. Although diet and exercise may reduce obesity in OSA adults, this has a very low success rate due to low compliance. Patients treated with gastric surgery may get better results if the weight loss achieved is permanent. Other treatment approaches include myofunctional therapy, oxygen therapy, oral pressure therapy, tongue stabilization therapy, cervicomandibular collars, and oral surgery.
Of these approaches, only surgery and permanent weight loss appear to offer possible “cures” for the condition.
What Kinds Of Oral Surgery Are Used To Treat OSA?
Oral surgery involving the oropharynx, nasal cavity, tongue, hyoid bone, throat, and jaws have all been used to treat OSA. Operations involving the uvula, tonsillar pillars, and septum aim to increase airflow through the oropharynx. Tongue surgeries attempt to pull the tongue forward, pull the back of the tongue down, make the tongue smaller, or stimulate the tongue to increase the tonicity of its muscles. These surgeries are only successful if these structures are actually a factor in the collapse of the oropharynx. There is no evidence that a SARME helps prevent this collapse and is not typically indicated for treating OSA. The most aggressive and most successful surgical procedure used to treat OSA is the two-jaw maxillomandibular advancement (MMA).
Why Would A Patient Need Maxillomandibular Advancement?
The maxillomandibular advancement provides a “cure” for OSA in 86% of patients. Patients may choose this option if they can’t tolerate CPAP, or oral appliances, are young and don’t want to spend the rest of their lives wearing CPAP or devices, or if other craniofacial issues exist that justify the movement of the jaws. The biggest challenge for these patients is the change in the occlusion after both jaws are moved. This is why MMA is always performed in conjunction with orthodontic treatment. Although highly successful, there are still 14% of patients who still have problems with their oropharynx collapsing after surgery (not surprising since OSA is not merely an anatomical condition).
What Treatments Actually Help Children With OSA?
Weight loss alone eliminates OSA in over 50% of young patients who can comply (obesity being the #1 risk factor). Hypertrophic adenoids and tonsils are the second most common cause of breathing disorders in children, and adenotonsillectomy (T&A) is still the treatment of choice.
If there is an accompanying maxillary constriction, the attending physician may prescribe RME therapy AFTER a T&A. Otherwise, for non-OSA orthodontic patients, there is no reason to expand “in the name of airway” if there is no maxillary transverse deficiency or crossbite.
What Is The Appropriate Role Of The Orthodontist In OSA?
The most critical thing orthodontists can do is understand the disease. A realistic review of the most current data suggests that orthodontists cannot predict, prevent, diagnose, or correct OSA. However, our role is to screen for the condition, identify those who exhibit signs and symptoms, make referrals to the appropriate physicians, and then possibly provide adjunct procedures or oral appliances as prescribed explicitly by those physicians. It is out of the scope of orthodontic practice to treat OSA on our own.
Can We Prevent Or Cure OSA In Our Patients?
Importantly, no one has shown that maxillary expansion (with or without TAD support) prevents or cures OSA.
“The effects of RME for children with OSA is mostly supported by low-quality studies (no control groups to compare patients against normal growth) … randomised trials [have] found no grounds for its use.”
There is no evidence that merely expanding the palate (including the nasal cavity) reduces “OSA parameters.” This is because the size of the nasal cavity is not linked to the collapsibility of the oropharynx. In other words, increasing the size of the underlying skeletal structures does not ensure that the overlying “soft structures” will follow suit or respond differently. Dr Charles Guilleminault, a pioneer in the field of sleep medicine, addressed the use of frenectomies to treat OSA. In his lecture, he suggested that only frenectomies performed in the first year of life have any benefit for OSA. Although there may be other reasons to implement them after age 1, OSA is not one of them.
How Can Orthodontists Screen For OSA In Their Practices?
There are two essential tools that every orthodontist can implement right away. First, the Pediatric Sleep Questionnaire (PSQ) is currently the best way to identify OSA in children you see in your practice. It is a simple one-page form that is easy for parents to fill out and for orthodontists to interpret. Currently, the STOP-BANG survey is the best screening tool orthodontists can use to identify adults who have or are at risk of having OSA. When we suspect a patient has OSA, we should refer them to an appropriate ENT or sleep medicine physician.
What Can’t Or Shouldn’t Orthodontists Do Relative To OSA?
Orthodontists cannot predict, prevent, diagnose, or cure sleep apnea. We should not use treating the “Airway” as an excuse for advocating specific approaches to treatment. For example, early palatal expansion, non-extraction treatment, non-retraction treatment, etc.
“When one considers the complex multifactorial nature of the disease, assigning the cause of OSA to any one minor dental factor or change in dentofacial morphology is not logical. In spite of this, people create misinformation and widely disseminate it.”
The Urgency For A Consensus On OSA
The title of the Winter Conference was “Sleep Apnea and Orthodontics: Consensus and Guidance” for a specific reason. When the orthodontic profession is under attack from all sides, the last thing we need is misleading advertising and verbiage that divides us.
This task force found that orthodontists can neither prevent, cause, nor cure OSA. I applaud those in our profession who recognised the importance of screening for and referring potential OSA patients to physicians for treatment even before this conference.
It is imperative that we all come to a consensus and present a consistent message to the public and our dental colleagues before the OSA issue spins out of control.
Thanks, Greg. This is a great summary. I am going to digest all this information, and then I will write a blog post about this issue and the “new speciality” of airway-focused orthodontics…In the meantime, thanks for all this very useful information.
Emeritus Professor of Orthodontics, University of Manchester, UK.