title: [Distortion of the anterior airway anatomy and cervical spine motion during laryngoscopy with GlideScope videolaryngoscope: a comparison of mid-size blade vs large blade].
abstract: BACKGROUND
  GlideScope videolaryngoscope (GVL) is a novel indirect laryngogoscope for tracheal intubation. Both mid-size and large blades of the GVL are available for adult patients. The distortion of the anterior airway anatomy and cervical spine motion using the mid-size GVL is unknown. We compare the degree of anterior airway distortion and cervical spine movement during the use of the mid-size GVL compared with the large GVL.
  
  
  METHODS
  Twenty patients requiring general anesthesia and tracheal intubation were studied. Each patient underwent laryngoscopy with both mid-size and large GVLs. During each laryngoscopy, a radiograph for the lateral view of the head and neck was taken when the best view of the larynx was obtained. Based on the radiographs, independent radiologists evaluated anterior airway movement and cervical spine movement.
  
  
  RESULTS
  The tip of the mid-size GVL was anteriorly positioned during laryngoscopy, compared with large GVL. The distance between epiglottis and posterior laryngeal wall was longer with the mid-size GVL than with the large GVL. Both the mid-size and large GVL caused a significant anterior movement in the cervical spine during laryngoscope. The difference in the movement in the atlas and C2 was small, but statistically significant. No difference was found in the anterior movement with C3 and C4. During laryngoscopy, cervical spinal extension occurred with both GVLs, while there was no difference in the cervical spinal extension between the mid-size and large GVL.
  
  
  CONCLUSIONS
  The tip of the mid-size GVL during laryngoscopy is anteriorly positioned and the distortion of the anterior airway was greater with the mid-size GVL than with the large GVL.
authors.affiliation: Jichi Children's Medical Center Tochigi, Shimotsuke 329-0498.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hirabayashi
authors.forename: Akifumi
authors.initials: A
authors.lastname: Fujita
authors.forename: Hideharu
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Norimasa
authors.initials: N
authors.lastname: Seo
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000502:physiology*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000295:instrumentation; D007830:Larynx / Q000033:anatomy & histology*; D009068:Movement; D014741:Video Recording