Obstructive Sleep Apnea
Obstructive sleep apnea is a well-known sleep related breathing disorder characterized by repetitive breathing cessations during sleep due to total collapse of the tissues in the throat. This can occur anywhere from a few times every hour to over 100 times every hour. By definition, an "apnea" is defined a total cessation of breathing for 10 seconds or more. "Hypopnea" is restricted breathing with greater than 30% chest wall movement decrease and blood oxygen drop more than 4%, for 10 seconds or more. The total combination of apneas and hypopneas for the entire night, divided by the total number of hours one sleeps, gives us the apnea hypopnea index, or AHI. This is the most commonly used measure to diagnose obstructive sleep apnea.
Although somewhat randomly set, obstructive sleep apnea is considered "positive" if your apnea hypopnea index is greater than 15, or between 5 and 15, if you have any of the medical consequences of obstructive sleep apnea (excessive fatigue, depression, hypertension, etc.). There are recent studies suggesting that even numbers under 5 are linked to cardiovascular disease. In children, the threshold number is considered to be 1. The irony is, if you are 17 years old and have an AHI of 14 (meeting the criteria for OSA), but when you turn 18, technically, you don’t have OSA. Obviously, diagnosing and treating OSA and UARS should be individualized based on the entire clinical picture, rather than on one simple arbitrary number.
To confuse matters even more, some sleep researchers use the term RDI or respiratory disturbance index. The RDI is the total number of apneas and hypopneas, plus the total number of awakenings due to anything less than an apnea or hypopnea, divided by the total sleep time. This takes into account all arousals, even is you obstruct for one second and wake up. Most arousals are subconscious, so you don't even realize that you are constantly aroused from deep sleep into light sleep. This happens more because as you enter deeper levels of sleep, the muscles in your throat (and all over your body) tend to relax, and the protective reflexes that keep your airway open diminish, predisposing to total collapse.
Untreated, obstructive sleep apnea has been strongly linked to obesity, frequent urination, hypertension, loss of sexual desire, diabetes, heart disease, heart attack and stroke. It is estimated that 80-90% of obstructive sleep apnea in this country is not diagnosed. This is an epidemic in this country, along with all the various cardiovascular conditions such as high cholesterol, diabetes, high blood pressure, and heart disease. The obesity epidemic just makes it worse, since weight gain is directly proportional to your risk of having obstructive sleep apnea. Not only fat can narrow the throat. Muscle mass can also narrow the throat, aggravating obstructive sleep apnea. Reggie white (the ex-football player) was known to have untreated obstructive sleep apnea. One study revealed that up to 1/3 of all NFL linemen has obstructive sleep apnea. What's worse, physicians, as well as the lay public, still believe that one has to be an older, heavy-set, snoring man to have obstructive sleep apnea. In fact, recent studies have shown that even young thin women that do not snore can have severe obstructive sleep apnea.
Furthermore, it's been shown that inefficient sleep (apnea or insomnia) can lead to weight gain. Experimentally sleep deprived subjects were found to have significantly increased levels of cortisol, which is known to increase one's appetite, and promote weight gain. Cortisol also lowers your immune systems’s ability to fight infections. Another recent study suggested that sleep deprivation causes one to prefer to eat unhealthy foods. Furthermore, sleep deprived people have lower levels of leptin, which is a hormone that lets people know they had enough to eat. Ghrelin, another hormone that makes people want to eat, increases with less sleep. This coupled with being too tired to exercise more during the day, only aggravates the sleep apnea-weight gain viscous cycle.
Other various hormones are also elevated which increased glucose in your bloodstream (link to diabetes), and which causes one to produce more urine. One recent urology paper found that the vast majority of older men who presented complaining of frequent urination had obstructive sleep apnea.
Obstructive sleep apnea is also implicated in complications during pregnancy. Pre-eclampsia, a dangerous elevation of blood pressure later in pregnancy, has been shown to be helped sometimes by treating for obstructive sleep apnea.
A significant number of children (25 to 30%) with attention deficit hyperactivity disorder are found to have obstructive sleep apnea. Once treated, many can come off their medications. A recent study published in Pediatrics found that one year after tonsillectomy, about 50% of children that originally met the official criteria for ADHD no longer had this disorder.
As you can see, obstructive sleep apnea is involved in almost every aspect of health and disease, and is one of the most underappreciated, but potentially treatable conditions.
There are many theories on why people develop sleep apnea, but we do know that as you get older, your risks increase dramatically. Obviously, there are many different factors that make one predisposed, including heredity, weight, facial anatomy, nasal allergies or congestion, sex, etc.
The one paradigm shift that occurred with me that made everything make more sense is to assume that all humans are susceptible to upper airway collapse, and that everyone is somewhere along a sleep-disordered breathing "continuum". To say that one has mild or severe sleep apnea, or to tell someone that if their apnea hypopnea index is 16 they have sleep apnea, but if their score is 14, they don't have it, is nonsense. Also, everyone has different levels of adjustment and accommodation to different levels of sleep apnea. Some patients with a score of 11 is severely affected, and others who stop breathing 60 times every hour are completely asymptomatic (except for their high blood pressure). Furthermore, the sleep studies have their own limitations; as good as they are, the numbers have to be taken with a grain of salt: You're sleeping in a strange bed, all hooked up to multiple wires, unable to turn easily in bed. Fortunately, for most people the amount of data that is collected is adequate for interpretation.
One interesting article that ties things together is the hypothesis that due to descent of the voice box during evolution to accommodate for speech, language and articulation, the tongue and palate are susceptible to collapse. No other animal has this feature. As far as we can tell, only humans have sleep apnea (certain dogs such as the bulldog snores, but they do not have sleep apnea).
Another interesting theory proposed by a dentist is that only modern man has obstructive sleep apnea. He cites his studies on prehistoric skulls and found that compared to modern human, their jaw structure and bite were much more ideal, and less crowding on the teeth. He attributes the onset of obstructive sleep apnea to bottle feeding. The artificially high negative pressure and the unnatural positioning of the tongue during suckling is thought to cause abnormal jaw development, leading to a crowding of the tongue.
Whether or not one believes any of this, sleep apnea is a serious problem in today's society.
Why does sleep apnea happen? For too many years doctors of different specialties focused too much on their respective areas. Just like in the tale of the five blind mice describing different parts of the elephant, doctors guilty of the same. Otolaryngologists, like myself, focused too much on the soft palate. Dentists focused too much on the tongue. Allergists on inflammation. Neurologists on a neurologic deficit. Pulmonologists on airway resistance and compliance.
A complete explanation on how obstructive sleep apnea occurs is too complex to describe here, especially when we still don't know exactly why (if we did, I wouldn't need to write this). Over the past few decades, we've come to realize that the entire upper airway must be considered, from the tip of the nose to the voice box. As a historical note, before the development of treatments for sleep apnea, the only way to treat this condition was by performing a tracheotomy, where a hole was made surgically just underneath the voicebox. This worked 100% of the time. But for obvious reasons, not too many people choose this option.
Think about the upper airway as a long thin tube, compliant at three sites (equivalent to the nose, palate and tongue). Imagine that your lungs are at one end and your nose is the other end. If you suck air on one end, while pinching the "nose" part on the other side, the two middle compliant parts (tongue or palate) can collapse, depending on the compliant of that portion of the tube. For example, the more compliant the palate is, or the more narrow it starts off, the more likely it will close down. Similarly, if you pinch the middle part of the tube and suck air in, the tip (nose) can collapse, again depending on the rigidity or compliance in this area.
A real-life example almost everyone has experienced is when you catch a simple cold. Your nose gets stuffed up. Remember tossing and turning, not being able to sleep at all? Pinch your nose closed with your fingers and try to breath in forcefully. This is what it feels like when you are having an apnea. As mentioned previously, the deeper level of sleep one is in, the more "compliant" the tissues are, and more likely to collapse completely. This has been experimentally verified by taking healthy college students and subjecting them to formal sleep studies with their noses pinched shut. All were found to have significant obstructive sleep apnea. This has also been documented in severe nosebleed patients that have packing; most are found to have sleep apnea with the packs in place, and are generally miserable. This is why over that past 5 years I have stopped using nasal packs after any type of nasal surgery. Pregnant women with stuffy noses (and more snoring) in their third trimesters are also miserable. Add to that increased weight in general. I don't have to remind you what happens next.
The good news in the above examples is that all are temporary. Once the obstruction goes away, you catch up on your sleep, and you're back to normal. Only if the obstruction continues on a chronic basis does it lead to problems.
The next area to consider is the palate area, at the level of your tonsils. In young children enlarged tonsils are the most common reason for obstructive sleep apnea, and this is easily treated with tonsillectomy (most of the time). However, as one gets older, the tonsils shrink, and the soft tissues of the throat and palate begin to stretch inwards with every apnea. Some young adults are lucky (or unlucky) enough to have persistently enlarged tonsils and in general do much is a better after tonsillectomy (with or without a palatal operation). If you have small or no tonsils your chances on a palatal operation curing you of obstructive sleep apnea is about 40% only. There are a number of ways of predicting whether or not an adult will respond to palatal surgery for sleep apnea. In general, if you have small tonsils and you can't see at least some of your uvula (the thing that hangs down the middle of your throat) when you open your mouth, then a palatal operation alone is successful in 40%. What this means is that your tongue may also be involved.
When you have tongue involvement, this means that either your tongue falls back from a normal position sitting up to almost completely collapsed when on your back. In most people with this condition, one is breathing through a small slit about 1/8 to 1/4 of an inch wide between the back of the tongue and the back of the throat. When awake, the muscular "reflexes" keep the airway open, but during sleep (especially deep sleep), this reflex does not work, and the tongue falls back completely, leading to an apnea. Another variation might be that the tongue falls back only partially, causing a more forceful vacuum upstream, narrowing the palatal area, when can then collapse totally, or when air squeaks through a very small palatal opening, one starts to snore. This is why certain dental devices that pull the jaw forward, pulls the tongue forward, alleviating snoring.
As you can see from the above descriptions, if you place a pump on the "nasal" end of the long thin tube, and blow a gentle amount of air, the tube does not collapse. This is the basic principle behind a CPAP machine (continuous positive airway pressure). A soft padded mask is placed over your nose and a pre-measured amount of air pressure is delivered from a small bedside machine. CPAP is the first-line treatment for obstructive sleep apnea, and it works, but only if you use it. Due to obvious practical or logistical issues, many people are not able to use it consistently. Studies have shown compliance rates between 40-60%. In addition, intensive support and follow-through by the sleep medicine technicians and durable medical equipment was found to significantly increase the odds that you will do well and like your machine. Technology has advanced enough so that they are small enough to travel with, and there are hundreds of different masks, straps, and other gadgets that are available to suits one's needs.
I strongly encourage anyone with obstructive sleep apnea to at least try CPAP first, even if you have only mild sleep apnea. Despite your hesitation about CPAP and it's implications, once it’s tried, about 1/3 of my patients love it instantly, another third hate it, and the remainder have to get used to it and after a period of follow-up and adjustment, they can use it effectively.
Only after absolutely refusing CPAP, or if you tried it and hate it, can other options be discussed.
Before rejecting CPAP altogether, if your nose is stuffy and the pressure seems too uncomfortable, then treating your nasal congestion may allow you to use CPAP more effectively. Allergies or sinusitis may be treated with medications. A deviated nasal septum can be easily repaired. Not only can you breathe better through your nose in general, but you can use CPAP much is a more effectively.
As mentioned previously, a dental device can be made (by a dentist that specializes in this) to pull your jaw forward. This is effective in patients with mostly tongue involvement, and not appropriate for people with palatal level narrowing. The device is worn nightly, and incrementally advanced slowly to prevent jaw pain and bite changes. These devices have been shown to help significantly in appropriately selected people with mild to moderate sleep apnea.
Lastly, there are surgical options, but only if you've rejected or failed the other options.
Uvulopalatopharyngoplasty (or UPPP) was first described in the early 1980's (about the same time as CPAP). Initially, they had good success rates, but over time, the success rates dropped to about 40%.
A side note about success: One of the biggest frustrations is that people use different definitions of success. The most commonly used definition in our field is a greater than 50% drop in the AHI, and that final number has to be less than 20. Unfortunately, many studies vary significantly from this definition, and others use very unorthodox ways of defining success.
Over the years, researchers have discovered that in cases where a UPPP fails, the tongue is the main culprit. Once the tongue collapse is addressed as well, the "success" rate increases to ~75%. Many subsequent studies report success rates in the 70-80% range.
There are many ways of addressing tongue collapse. At Stanford, they perform (in addition to the UPPP) a mandibular osteotomy with genioglossus advancement (MOGA), and hyoid myotomy with suspension (HMS). MOGA involves advancing the portion of your tongue that attaches to the midline lower jaw, and HMS involves pulling the hyoid bone, which is a c-shaped bone on top of your voicebox that attaches to your tongue and voicebox. Of the 25% that fail this operation, a portion went on to more definitive surgery, called a maxillo-mandibular advancement. This is a complex and long procedure that literally pulls the middle of your face and jaw bones forward. As expected, this procedure is well more than 90% effective.
An alternative to the MOGA is a procedure where a suture is attached to the midline lower jawbone, and looped around the back of the tongue, thus suspending the tongue from falling back. Results are similar to the MOGA, but much less invasive.
One last word about palatal treatments for obstructive sleep apnea: There are various modifications of the UPPP procedure, which all have their roles for selected patients. A recent alternative to the UPPP for mild obstructive sleep apnea is an implant procedure called the Pillar procedure. Three thin polyester rods are implanted into the soft palate which causes a tightening of the soft palate as it heals over weeks to months. It was originally developed for snoring, but recently received FDA approval for mild obstructive sleep apnea. For treatment options on snoring, please refer to the snoring section on this website.
If you have any questions about sleep apnea or any of the treatment options, please contact Dr. Park.
Steven Y. Park, M.D.
Otolaryngology – Head & Neck Surgery
(212) 315-9058
