JCO Interviews Dr. Thomas Weimert on Airway Obstruction in Orthodontic Practice

DR. WEIMERT Polyps frequently recur, and patients are told this before they are removed. However, removal often provides the patient with several years of relief before another procedure is needed.

DR. GOTTLIEB Can polyps be seen radiographically?

DR. WEIMERT Polyps cannot be diagnosed radiographically, although complete opacification of the nasal airway on the PA head film in conjunction with radiographic evidence of sinus disease may be a tipoff that polyps are the source of the obstruction.

DR. GOTTLIEB Is mouthbreathing a frequent accompaniment to all these nasal obstructions?

DR. WEIMERT Every patient with nasal obstruction will mouthbreathe some of the time. In my experience, approximately 25 percent breathe with a mouth-open posture persistently.

DR. GOTTLIEB What's wrong with mouthbreathing from an ENT point of view?

DR. WEIMERT Patients who mouthbreathe bypass the normal humidification and warming functions supplied by nasal respiration and may develop a number of symptoms including headache, dry mouth, sore throat, halitosis, poor sleep, chronic fatigue, and ear pressure and fullness. Moreover, mouthbreathing is an inefficient form of respiration. It can be demonstrated clinically, for example, that exercise tolerance is markedly diminished in the patient with nasal obstruction. Nasal respiration and pulmonary function are complexly related. We know, for instance, that when the human nose is occluded, the arterial oxygen tension drops 10-15 percent, even in the healthy adult. So, when we are discussing nasal obstruction, we must remember that we are not just referring to patient comfort. It affects other bodily functions as well.

DR. GOTTLIEB We sometimes see obstructive techniques used in an attempt to overcome mouthbreathing--a positioner without airholes, for instance, or an oral shield. Can you make somebody who is a mouthbreather, either habitually or because of an obstruction, breathe through his nose rather than just dump the appliance out because he can't do that?

DR. WEIMERT If there is a significant mechanical nasal airway obstruction, the patient will not be able to overcome the mouthbreathing by conscious effort. On the other hand, the person who is mouthbreathing out of habit may well benefit by a concerted effort to keep the mouth closed.

DR. GOTTLIEB It doesn't overcome obstruction?

DR. WEIMERT No. In fact, the greater the effort to draw air in through the nose, the more turbulence is created in the airflow pattern, and a smaller volume of air is inspired. You cannot overcome an obstruction by forcibly breathing through the nose.

DR. GOTTLIEB People have an idea that you measure the ability to breathe by intake, and actually it is measured by resistance. Is that correct?DR. WEIMERT The volume of air inspired is inversely proportional to the airway resistance. In an attempt to quantify degrees of nasal obstruction, some investigators measure nasal resistance using rhinomanometry. The nose normally accounts for over 50 percent of overall ventillatory resistance. As nasal resistance increases, pulmonary resistance increases.

DR. GOTTLIEB What is the nasal cycle?

DR. WEIMERT The nasal cycle is an important concept to understand in evaluating the nasal airway. The lining of the nose cyclically swells and shrinks. When one side of the nose congests, the other side will simultaneously decongest. In the normal individual, the overall nasal resistance remains constant. This cyclical variation in the nasal chambers is demonstrable in over 90 percent of adults and occurs every half-hour. When the architecture of the nose is abnormal (i.e., deviated septum), the nasal cycle may result in intermittent obstruction.

DR. GOTTLIEB How much do you interfere with the nasal cycle when you remove the turbinates?

DR. WEIMERT Two-thirds to three-fourths of total nasal resistance is related to the inferior turbinates. Therefore, the inferior turbinates are never completely removed. As a result, the obstruction is relieved, but the nasal cycle is still operational.

DR. GOTTLIEB Moving backward from the nose, I guess the next airway problem is with the adenoids and tonsils. When do the tonsils become obstructive?

DR. WEIMERT In my experience, tonsils do not commonly cause true airway obstruction. Fewer than 1 percent of my patients undergo a tonsillectomy for reasons of airway obstruction. We grade tonsil enlargement on a 1 + to 4 + scale. The 1 + tonsils are barely visible; 2 + are small, but visible; 3 + are generous in size; and 4 + are truly obstructive and meet in the midline.

DR. GOTTLIEB Do you use lateral x-rays to diagnose tonsil obstruction?

DR. WEIMERT I have not found radiographs to be particularly helpful in evaluating tonsil size. The lateral cephalogram is two-dimensional and only gives an overall impression of tonsil size. Direct visualization is far more useful.

DR. GOTTLIEB Is there any more precise measurement than the 1 + to 4 + gradations?

DR. WEIMERT Unfortunately, it is a very subjective evaluation. Tonsil size varies widely and fluctuates greatly. We do not have an objective way of measuring tonsil size relative to the volume of the pharynx and hypopharynx.DR. GOTTLIEB What is the function of the tonsils?

DR. WEIMERT Tonsils and adenoids are composed of lymphoid tissue. We know that tonsils produce antibodies and that they have a role in the formation of lymphocytes, which are critical in the body's immune system.

DR. GOTTLIEB Are the tonsils and adenoids indispensable to the body's immune system?

DR. WEIMERT No. Removal of the tonsils and adenoids has not been shown to affect a person's health adversely. Lymphoid tissue resides in other areas of the oropharynx. The lingual tonsils, for example, remain after a tonsillectomy and adenoidectomy.

DR. GOTTLIEB Years ago, everyone had his tonsils removed. Then we went into a much more conservative phase. Why the change?

DR. WEIMERT Many disease entities in the past were attributed to the tonsils and adenoids. Many years ago, tonsils and adenoids were removed almost prophylactically and--in retrospect--probably unnecessarily. Then, an anecdotal study published in one of our major medical journals suggested an association between tonsil removal and malignancy. The pendulum swung the other way, partly as a result of the article, and removal of tonsils and adenoids was discouraged. That study has since been disproven. Today, we are more selective in recommendations for tonsillectomy and adenoidectomy. We are better educated regarding conditions that are caused by the tonsils and adenoids. Refinement in surgical and anesthesia techniques have also diminished the morbidity and mortality of the procedure.

DR. GOTTLIEB What is the indication for removing tonsils today?

DR. WEIMERT The most common indication is recurrent infection. Rarely, marked tonsillar hypertophy can lead to corpulmonale or sleep apnea. These are absolute indications for removal. Tonsils do not commonly contribute to mouthbreathing in my experience.

DR. GOTTLIEB Can tonsils grow back?

DR. WEIMERT Tonsils do not grow back if they are removed properly. The palatine tonsils are encapsulated. There are other areas of lymphoid tissue in the pharynx, however, that can hypertrophy and become symptomatic (e.g., lingual tonsils) even after the palatine tonsils are removed.

DR. GOTTLIEB How do you evaluate the adenoids?

DR. WEIMERT There are two effective means of evaluating adenoid size. The first is indirect visualization with the nasopharyngeal mirror. This is not always possible in the young child. The second is the lateral soft tissue x-ray. This is very helpful. The size of the adenoid pad on the x-ray correlates very well with what we ultimately find surgically. It is helpful to me when a referring orthodontist sends the lateral cephalogram along with the patient referred for an ENT evaluation.

DR. GOTTLIEB Do you ever use special x-ray techniques to evaluate the adenoids?

DR. WEIMERT Usually not. The lateral soft tissue x-ray is usually adequate. Occasionally, a tomogram is helpful.

DR. GOTTLIEB What is the difference between adenoid and tonsillar tissue?

DR. WEIMERT The big difference is that the adenoids are not well encapsulated. They are an integral part of the mucosal lining of the nasopharynx, and really cannot be completely removed as the tonsils can.