title: Tongue and lateral upper airway movement with mandibular advancement.
abstract: OBJECTIVE
  To characterize tongue and lateral upper airway movement and to image tongue deformation during mandibular advancement.
  
  
  METHODS
  Dynamic imaging study of a wide range of apnea hypopnea index (AHI), body mass index (BMI) subjects.
  
  
  METHODS
  Not-for-profit research institute.
  
  
  METHODS
  30 subjects (aged 31-69 y, AHI 0-75 events/h, BMI 17-39 kg/m(2)).
  
  
  METHODS
  Subjects were imaged using dynamic tagged magnetic resonance imaging during mandibular advancement. Tissue displacements were quantified with the harmonic phase technique.
  
  
  RESULTS
  Mean mandibular advancement was 5.6 ± 1.8 mm (mean ± standard deviation). This produced movement through a connection from the ramus of the mandible to the pharyngeal lateral walls in all subjects. In the sagittal plane, 3 patterns of posterior tongue deformation were seen with mandibular advancement-(A) en bloc anterior movement, (B) anterior movement of the oropharyngeal region, and (C) minimal anterior movement. Subjects with lower AHI were more likely to have en bloc movement (P = 0.04) than minimal movement. Antero-posterior elongation of the tongue increased with AHI (R = 0.461, P = 0.01). Mean anterior displacements of the posterior nasopharyngeal and oropharyngeal regions of the tongue were 20% ± 13% and 31% ± 17% of mandibular advancement. The posterior tongue compressed 1.1 ± 2.2 mm supero-inferiorly.
  
  
  CONCLUSIONS
  Mandibular advancement has two mechanisms of action which increase airway size. In subjects with low AHI, the entire tongue moves forward. Mandibular advancement also produces lateral airway expansion via a direct connection between the lateral walls and the ramus of the mandible.
  
  
  BACKGROUND
  Brown EC; Cheng S; McKenzie DK; Butler JE; Gandevia SC; Bilston LE. Tongue and lateral upper airway movement with mandibular advancement. SLEEP 2013;36(3):397-404.
authors: Neuroscience Research Australia, Randwick, NSW, Australia.
authors: Elizabeth C
authors: EC
authors: Brown
authors: Shaokoon
authors: S
authors: Cheng
authors: David K
authors: DK
authors: McKenzie
authors: Jane E
authors: JE
authors: Butler
authors: Simon C
authors: SC
authors: Gandevia
authors: Lynne E
authors: LE
authors: Bilston
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D019186:Mandibular Advancement / Q000379:methods*; D008875:Middle Aged; D010614:Pharynx / Q000033:anatomy & histology*; D017286:Polysomnography / Q000379:methods; D020181:Sleep Apnea, Obstructive / Q000517:prevention & control; D014059:Tongue / Q000033:anatomy & histology*; D016896:Treatment Outcome
keywords: Obstructive sleep apnea; lateral walls; mandibular advancement splint; pterygomandibular raphe