Are there good imaging studies of upper airway obstruction in sleep apnea patients?
This question was submitted by a general dentist:
Are there good imaging studies of upper airway obstruction in Sleep apnea patients? I see patients with Cpap machines and sleep studies; but there does not seem to be any airway imaging to assess the ability of these patients to breathe normally. Can surgical intervention in the upper airway provide a significant improvement? I have seen amazing results with patients having a bi-maxillary advancement.
Dr. Reginald Goodday, Professor and Chair in the Department of Oral and Maxillofacial Sciences at Dalhousie University provided this quick initial response
Imaging modalities are adjuncts to making a diagnosis of obstructive sleep apnea (OSA). The actual diagnosis is made using a thorough history, physical exam, and overnight polysomnography.
Imaging helps identify the sites of obstruction in the pharynx and associated anatomic abnormalities. However, imaging is limited because typically the patient is awake and most often is standing which does not represent the clinical conditions under which obstructive sleep apnea takes place.
Cephalometric radiographs are useful to identify anatomic abnormalities and to plan surgery and the required advancement of the maxilla and mandible. They are also useful to show the difference between pre- and post-surgery airways. The advantage of cephalometric radiographs is the fact that they are widely available, relatively inexpensive, and have a low radiation exposure. The drawback of this type of radiograph is that it is 2 dimensional and the image is only of the sagittal plane. In addition, the patient is again awake and in an upright position.
Magnetic resonance imaging can be used to look at the soft tissue of the pharynx; however, the patient typically is awake, and a significant drawback is high cost and low availability. An MRI is not helpful for planning skeletal surgery.
There is consensus that cone beam computed tomography (CBCT) is the method of choice for examination of the airway in the oral and maxillofacial surgeon’s office. This technology allows 3-D volumetric imaging which shows good delineation of the soft tissue airway and excellent assessment of the bony anatomy. Compared to the medical CT, there is less radiation exposure, greater access, and lower cost.
With regard to surgical intervention providing a significant improvement, these are the results of a recent study conducted at Dalhousie University. Out of 116 OSA patients treated with maxillomandibular surgery, 83% of patients did not snore post surgery, 94% had no witnessed apneas following surgery, and out of 106 patients, 95% did not need CPAP following surgical treatment.
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Good thought about what else might be causing someone to have to use a cpap at night. Having the test done while they are not in an upright position makes sense that they might need to clear a blockage rather than just the airway. Good points.
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I am particularly interested in the topic. I’m doing my PhD in mechanical engineering at Stanford, my focus is soft tissye modeling and I got very interested in Obstructive Sleep Apnea. I’m currently looking into performing airway simulations, would it be useful to use computational simulations to predict the sleep geometry out of the awake geometry? Thanks for your feedback.