title: Distortion of anterior airway anatomy during laryngoscopy with the GlideScope videolaryngoscope.
abstract: OBJECTIVE
  A non-line-of-sight view is expected to cause less movement of the anterior airway anatomy and cervical spine during laryngeal visualization. Reduced distortion of anterior airway anatomy during laryngoscopy with the GlideScope videolaryngoscope (GVL), compared with the Macintosh laryngoscope, could explain the relatively easier nasotracheal intubation with the GVL. The purpose of this radiographic study was to compare the degree of anterior airway distortion and cervical spine movement during laryngoscopy with the GVL and the conventional Macintosh laryngoscope.
  
  
  METHODS
  Twenty patients requiring general anesthesia and tracheal intubation were studied. Each patient underwent laryngoscopy using the first-generation GVL and a direct laryngoscope with a Macintosh blade. During each laryngoscopy, a radiograph was taken when the best view of the larynx was obtained. Independent radiologists with subspeciality training in musculoskeletal imaging evaluated anterior airway distortion and cervical spine movement.
  
  
  RESULTS
  The distance between the epiglottis and the posterior pharyngeal wall during the GlideScope procedure was 21% less than that during the Macintosh laryngoscopy (P < 0.05). Anterior deviations of the vertebral bodies from baseline were 27, 32, 36, and 39% less at the atlas, C2, C3, and C4 vertebrae, respectively, during the GlideScope procedure than those measured during Macintosh laryngoscopy (P < 0.01). Cervical extension between the occiput and C4 during the GlideScope procedure was 23% less than that during Macintosh laryngoscopy (P < 0.05).
  
  
  CONCLUSIONS
  Both anterior airway distortion and cervical spine movement during laryngeal visualization were less with the GVL than with the Macintosh laryngoscope.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan. yhira@jichi.ac.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Akifumi
authors.initials: A
authors.lastname: Fujita
authors.forename: Norimasa
authors.initials: N
authors.lastname: Seo
authors.forename: Hideharu
authors.initials: H
authors.lastname: Sugimoto
mesh_terms: D000328:Adult; D000768:Anesthesia, General; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000379:methods*; D007830:Larynx / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008875:Middle Aged; D009068:Movement; D011859:Radiography; D015203:Reproducibility of Results; D013131:Spine / Q000033:anatomy & histology / Q000000981:diagnostic imaging