What is the accuracy of sleep endoscopy?

Updated: Aug 21, 2019
  • Author: Philip E Zapanta, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Answer

Due to the subjective nature of evaluating airway collapse during sedation, the question of sleep endoscopy’s reliability is a concern.

When comparing assessments by 2 independent reviewers of prerecorded sleep endoscopy procedures, Kezirian et al demonstrated moderate to substantial interrater reliability. This was significant in the identification of primary structures involved in obstruction versus individual structures. [10]

This same study demonstrated a higher interrater reliability for assessment of the palatal region for obstruction in general versus assessment of individual structures that cause obstruction in the palatal region. The authors stated that the lower reliability in assessing individual structures is less important in palatal obstruction, because traditional uvulopalatopharyngoplasty (UPPP) treatment is the same regardless of the structure involved, be it the soft palate or velopharynx lateral pharyngeal wall.

(However, there has been developing interest in UPPP modifications. These include the expansion pharyngoplasty, [11] uvulopalatal flap, [12] anterior palatoplasty, [13] and Z-palatopharyngoplasty. [14] Each of these modifies the palate in various ways, creating either a superior and lateral pull, an anterior pull, or a combination pull on the palate and pharynx. Application of these specific palate procedures based on DISE could change how the palate is addressed.)

Kezirian et al's study also mentions that the tongue, epiglottis and lateral pharyngeal walls are the 3 structures most commonly involved in obstruction in the hypopharynx. At this site, there is a moderate to substantial interrater reliability in assessing individual hypopharyngeal structures that cause obstruction. Because there are varying treatment options for the different structures that are involved, sleep endoscopy can help to determine which hypopharyngeal and oropharyngeal procedure will be the most efficacious.

A study by Rodriguez-Bruno et al concluded that sleep endoscopy has good reliability, particularly in the evaluation of hypopharyngeal structures. The investigators looked at test-retest reliability, comparing the results from 2 distinct exams analyzed by 1 person. [15]

When retrospectively reviewing more than 2,400 procedures involving patients with symptoms of sleep-disordered breathing, Kotecha et al demonstrated greater than 98 percent effectiveness of sleep endoscopy in producing snoring in patients. This conclusion was important, because in order for sleep endoscopy to be a valid tool for evaluating obstruction, it has to be proficient in recreating sleeplike conditions. [16]

Concerns regarding the potential for false-positives with sedation revolve around the premise that sedation-induced sleep can cause a greater degree of muscle relaxation than physiologically natural sleep does. [17] Critics argue that snoring may be induced in the patient who otherwise would not exhibit symptoms during normal sleep. [18]

However, when nonsnorers who underwent similar sedation techniques were compared with individuals with self-described snoring problems, the nonsnorers were not induced to snore with sedation. [19, 20]

Another concern with sleep endoscopy is whether or not the sedation-induced sleep alters the sleep profile. Rabelo et al showed that patients induced with propofol did not enter rapid eye movement (REM) sleep during sedation and that these patients tended to remain in slow-wave sleep. When the apnea-hypopnea indexes (AHIs) between propofol-induced patients and those whom slept without sedation were compared, there was little difference between the groups. Although the fundamental sleep architecture is changed in a patient with OSA, propofol has been shown to not change the respiratory pattern in patients with apnea; [20]

Another study demonstrated a reduction in the duration of REM sleep in patients undergoing DISE; however non-REM sleep patterns were unchanged. [21] It is important to note that, although it is believed that the majority of apneic events occur during REM sleep, research has shown that AHIs measured during REM and non-REM sleep in patients with OSA do not differ significantly. [22]

Intraprocedural grading using any of the methods described above typically correlates well with results of AHI, and it has been shown that AHIs measured after targeted therapy directed by sleep endoscopy are significantly lower.

In a study comparing 207 primary snorers without OSA with 117 subjects with OSA after receiving sedation, a higher degree of collapsibility was seen in the OSA group, with a correlation observed between the AHI during natural sleep and the degree of hypopharyngeal obstruction during sleep endoscopy. [23]

It is becoming more and more recognized that the utility of DISE easily surpasses the information gained from awake endoscopy in a clinic. A recent study concluded that DISE yielded better results as to specific sites, degree, and patterns of obstruction compared with the awake Muller maneuver. [24]


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