2D and 3D Airway Analysis and Mandibular Advancement Treatment Outcome in Obstructive Sleep Apnea
thesisposted on 21.07.2015 by Whitney Mostafiz
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Hypothesis: Oropharyngeal 2D and 3D airway variables will be associated with MAS treatment response in terms of change in respiratory disturbance index (RDI) and change in minimum oxygen desaturation (SaO2). The association between oropharyngeal 2D and 3D airway variables with MAS treatment response will depend on sleep position, sleep state, mandibular protrusion, initial OSA severity, BMI, and neck circumference. Objective: To identify the association between oropharyngeal airway dimensions derived from cone beam computed tomography (CBCT) and MAS treatment response, and to determine whether it is affected by mandibular protrusion, sleep state, sleep position, initial OSA severity, BMI, and neck circumference. Methods: Thirty-three adults were assessed retrospectively. Dolphin 3D was used to measure the airway in pretreatment CBCTs. Airway volume, length, and minimal cross-sectional area (CSA) were calculated, as well as transverse and A-P dimensions and minimal CSA location. Pre- and post-treatment polysomnograms (PSGs) assessed OSA severity via RDI, and changes in minimal SaO2, supine and non-supine RDI, and NREM and REM RDI. Results: This study included 23 males and 10 females. Ten, fifteen, and eight initially presented with mild, moderate, and severe OSA, respectively. Oropharyngeal 2D and 3D airway variables were associated with treatment response. Multivariate models explained treatment response, wherein initial OSA severity was a primary predictor in four models, and the combination of total airway volume and initial BMI were predictors in two models. Conclusions: Patients with higher initial OSA severity and smaller airway volumes may have increased response to MAS therapy. Decreases in airway volume due to skeletal rather than soft tissue obstruction may enable better MAS treatment response. Since MAS targets upper airway, patients with superior airway constriction illustrate increased treatment response potential as well as decreased titration to achieve desirable outcome.