Computer-Assisted Quantitative Evaluation of Obstructive Sleep Apnea Using Digitalized Endoscopic Imaging with Muller Maneuver
ABSTRACT To validate the technique of the Muller maneuver (MM) using videoendoscopy and to quantify the correlation between its clinical results and variables of polysomnography.
Prospective, controlled study.
Videoendoscopy with MM was performed in 70 patients who were categorized into two groups, with 35 patients giving a history suggestive of snoring and 35 patients without such history. The snoring group underwent further examination with polysomnography. Cross-sectional areas at the retropalatal (RP) and retrolingual (RL) levels during quiet respiration (RP(0) or RL(0)) and the maximal effort of MM (RP(1) or RL(1)) were calculated with the digital measurement software "Image J." One hundred forty pairs of data were acquired. The collapsing ratio (CR) was defined as the difference of RP(0) (or RL(0)) between RP1 (or RL(1)) divided by RP(0) (or RL(0)) to compare the difference between the two phases. These results were compared with each other and correlated to the variables obtained from polysomnographic studies.
There were significant differences in the CR of RP (CR(RP)), the CR of RL (CR(RL)), and body mass index (BMI) when comparing the two groups. In snoring patients, BMI was positively related to the respiratory disturbance index (RDI) and obstructive sleep apnea (OSA) staging but not to CR(RP) and CR(RL). CR(RP) had a significant positive relationship with RDI and OSA rather than CR(RL).
MM with videoendoscopy can be a simple, cost-effective, quantitative, and even predictable technique. This method allows us to examine the dynamic upper airway for more precise preoperative planning.
SourceAvailable from: Yasumasa Okada[Show abstract] [Hide abstract]
ABSTRACT: The Müller maneuver has been widely applied to mimic the pathophysiological condition of obstructive sleep apnea (OSA) during wakefulness. We applied cine MRI to elucidate dynamics of the upper airway during the Müller maneuver in healthy subjects (n = 7). Three sets of images (during quiet nose breathing, quiet mouth breathing, and Müller maneuver) were recorded on sagittal midline plane together with impedance pneumography. The position of the tongue root changed during a respiratory cycle when subjects breathed quietly. At the early inspiratory phase the tongue root moved forward and upward, the retroglossal airway size increased toward the middle of inspiration, and the airway size became smaller again toward the end of inspiration. During expiration the airway size became further smaller. When the subject performed the Müller maneuver, the movement of the oropharynx and its narrowing were greater than those of the velopharynx. However, the airway was not completely obstructed. A relatively large morphological change was observed in the retropalatal and retroglossal regions with the backward and downward motion of the tongue root and flattening of the tongue shape during the Müller maneuver. Although patterns of upper airway narrowing and tongue shape alterations were variable among subjects, upper airway narrowing was commonly prominent in the retroglossal area. Cine MRI with the Müller maneuver enables to visualize the upper airway dynamics and could be easily applied to evaluate upper airway collapsibility during wakefulness.Advances in Experimental Medicine and Biology 01/2013; 788:189-95. DOI:10.1007/978-94-007-6627-3_28 · 2.01 Impact Factor
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ABSTRACT: Objectives To verify the effects of oral appliance (OA) on upper airway morphology under intraluminal pressure, identify specific sites of upper airway collapsibility that can be reversed by OAs, and determine the relationship between OA efficacy and dynamic upper airway changes using computed tomography (CT) with Muller’s maneuver. Materials and methods Nineteen adult Chinese patients with symptomatic mild-to-moderate sleep apnea were recruited from our sleep center. Each patient was fitted with a two-piece OA. Dynamic changes in the retropalatal and retroglossal airway were evaluated using CT at end-expiration and during Muller’s maneuver, both with and without an OA. Results Upper airway changes in the end-expiration phase before OA placement did not significantly differ from those after OA placement. However, under intraluminal pressure induced by Muller’s maneuver, OA effectively expanded the upper airway at multiple levels. In addition, OA counteracted negative intraluminal pressure more effectively in the retropalatal region than in the retroglossal region, with 95.65, 68.75, 72.41, and 78.38 % improvements in the collapsibility index of the anteroposterior dimension, transverse dimension, minimum cross-sectional area, and volume of the retropalatal region, respectively. Both nonresponders and responders to OA treatment were sensitive to the intraluminal pressure induced by Muller’s maneuver. However, the collapsibility of the retropalatal airway improved significantly only in the responders, not in the nonresponders. Conclusions OA effectively treats OSAHS by improving upper airway collapsibility.Sleep And Breathing 05/2014; 19(1). DOI:10.1007/s11325-014-0994-9 · 2.87 Impact Factor
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ABSTRACT: To understand: 1) how endoscopic airway measurements compare to three-dimensional (3D) CT derived measurements; 2) where each technique is potentially useful; and 3) where each has limitations. Compare airway diameters and cross-sectional areas from endoscopic images and CT derived 3D reconstructions. Videobronchoscopy was performed and recorded on an adult-sized commercially available airway mannequin. At various levels, cross-sectional areas were measured from still video frames using a referent placed via the biopsy port. A 3D reconstruction was generated from a high resolution CT of the mannequin; planar sections were cut at similar cross-sectional levels; and cross-sectional areas were obtained. At three levels of mechanically generated tracheal stricture, the differences between the endoscopic measurement and CT-derived cross-sectional area were 1%, 0%, and 7% (1.8, 0.8, and 14 mm²). At the vocal folds, the difference was 9% (7.8 mm²). The tip of the epiglottis and width of the epiglottis differed by 27% and 10% (18.73 mm², 0.40 mm). The airway measurements at the base of tongue, minimal cross-sectional area of the pharynx, and choana differed by 26%, 36%, and 30% (101.40 mm², 36.67 mm², 122.71 mm²). Endoscopy is an effective tool for obtaining airway measurements compared with 3D reconstructions derived from CT. Concordance is best in geometrically simple areas where the entire cross-section measured is visible within one field of view (trachea, round; vocal folds, triangular) versus geometrically complex areas that encompass more than one field of view (i.e. pharynx, choana).The Laryngoscope 09/2013; 123(9):2136-41. DOI:10.1002/lary.23836 · 2.03 Impact Factor