title: Cervical spine motion during tracheal intubation with manual in-line stabilization: direct laryngoscopy versus GlideScope videolaryngoscopy.
abstract: BACKGROUND
  The optimal tracheal intubation technique for patients with potential cervical (C) spine injury remains controversial. Using continuous cinefluoroscopy, we conducted a prospective study comparing C-spine movement during intubation using direct laryngoscopy (DL) or GlideScope videolaryngoscopy (GVL), with uninterrupted manual in-line stabilization of the head by an assistant.
  
  
  METHODS
  Twenty patients without C-spine pathology were studied. After induction of general anesthesia with neuromuscular blockade, both DL and GVL were performed on every patient in random order. Cinefluoroscopic images of C-spine movement during GVL and DL were acquired and divided into four stages: a baseline image before airway manipulation, glottic visualization, insertion of the endotracheal tube into the glottis, and tracheal intubation. Peak segmental motion from the occiput to C5 was measured offline for each patient and each stage, averages were calculated, and movements induced by each instrument were compared using a two-way ANOVA. Also studied were the proportion of patients with occiput-C1 rotation exceeding 10, 15, or 20 degrees, and the quality of glottic visualization.
  
  
  RESULTS
  No significant difference was found between DL and GVL regarding average segmental spine movement at any level (P values between 0.22 and 0.70). During both techniques, motion was mainly an extension concentrated in the rostral C-spine and occurred predominantly during glottic visualization. The proportion of patients with occiput-C1 extension of more than 10, 15, or 20 degrees was not significantly different. Glottic visualization was significantly better with GVL compared with DL.
  
  
  CONCLUSIONS
  During intubation under general anesthesia with neuromuscular blockade and manual in-line stabilization, the use of GVL produced better glottic visualization, but did not significantly decrease movement of the nonpathologic C-spine when compared with DL.
authors.affiliation: Department of Anesthesiology, Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, 1560 Sherbrooke East, Montreal, Canada H2L 4M1.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Robitaille
authors.forename: Stephan R
authors.initials: SR
authors.lastname: Williams
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Tremblay
authors.forename: François
authors.initials: F
authors.lastname: Guilbert
authors.forename: Mélanie
authors.initials: M
authors.lastname: Thériault
authors.forename: Pierre
authors.initials: P
authors.lastname: Drolet
mesh_terms: D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries / Q000503:physiopathology*; D002933:Cineradiography; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D007828:Laryngoscopy; D009068:Movement; D011446:Prospective Studies; D013124:Spinal Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013997:Time Factors; D020535:Video-Assisted Surgery