NASOPHARYNGOSCOPY

Dynamic nasopharyngoscopy is a test in which the physician uses a flexible fiberoptic scope to examine the upper airway. By examining the upper airway in this fashion, the physician can determine whether there are any fixed blockages in the upper airway such as a deviated septum or nasal polyps. By having the patient execute some simple manoeuvres, it is possible to demonstrate the dynamic behaviour of the airway under conditions that promote collapse or which help to prevent collapse.  For a view of the structures visible during dynamic nasopharyngoscopy, click here.

View of a nasal passage Structures that can be seen with the flexible scope are the nasal septum and the turbinates. Special note is taken of abnormal swelling, polyps and congenital abnormalities.

View of the nasopharynx Structures to note are the adenoids and the depth and height of the nasopharynx.

View of the velopharynx The velopharynx is bounded by the soft palate (seen at top), the back of the throat, and a muscle complex on each side.

View of the oropharynx and hypopharynx This is the part of the upper airway that contains the tonsils and the tongue.

View of the glottis This is a very complex structure that forms the gateway to the lungs and which produces speech.

Muller's Manoeuvre

Resting airway	Severe airway collapse during Muller's manoeuvre

In Muller's manoeuvre, the patient is asked to try and take a breath in while the mouth is closed and the nose is pinched shut. This generates a negative pressure in the upper airway. In patients who just snore, there may be slight inward movement of the soft palate and the back of the throat but the glottis remains visible. Patients who have OSA show varying degrees of collapse in the side walls of the velopharynx, at the base of the tongue, and at the back of the throat which narrows the airway by more than 25%. Patients who show the degree of collapse seen in this example usually have moderately severe OSA or worse.

Jaw Thrust

Resting airway	Airway with jaw thrust

Jaw thrust, or mandibular advancement, enlarges the airway by several mechanisms that depend on the intricate interrelationship between structures in the upper airway. The most obvious mechanism is that the base of the tongue is pulled forward. Pulling the jaw forward also lifts the throat muscles off the spine and places them under tension. Thus, thrusting the jaw forward enlarges and stabilizes the airway at several levels. Patients who show a good response to this manoeuvre can use a dental appliance for treatment of their snoring or OSA (provided that their teeth are in good shape).

At the Vancouver Sleep & Breathing Centre, we find that patients with small resting airways that are quite swollen and which collapse completely with Muller's maneuver invariably have Moderately Severe to Severe OSA. If these patients are also loud habitual snorer, it is reasonable to proceed with a trial of the CPAP using one of the intelligent CPAPs such as the Virtuoso from Respironics which uses snoring noises to adjust the pressure automatically. A sleep study would only be performed if the patient did not respond to the CPAP or confirmation of the diagnosis was required by the insurer.

In addition, we also find that patients who are loud, habitual snorers and who show good airway dilation with the jaw thrust can proceed directly to dental appliance therapy. Again, a sleep study would only be performed if the patient did not respond to the dental appliance or confirmation of the diagnosis was requested by the insurer.

The majority of health care expenditures for snoring and OSA should be allocated to treatment rather than diagnosis.

For a more-detailed explanation of dynamic nasopharyngoscopy, click here.

Dynamic Nasopharyngoscopy
Epworth Sleepiness Scale
Calculated Probability of Having OSA
Sleep Study
Stanford Method for Predicting OSA