title: The Effect of Cricoid Pressure on the Unstable Cervical Spine.
abstract: BACKGROUND
  It has been proposed that cricoid pressure can exacerbate an unstable cervical injury and lead to neurologic deterioration.
  
  
  OBJECTIVE
  We sought to examine the amount of motion cricoid pressure could cause at an unstable subaxial cervical spine injury, and whether posterior manual support is of any benefit.
  
  
  METHODS
  Five fresh, whole cadavers had complete segmental instability at C5-C6 surgically created by a fellowship-trained spine surgeon. Cricoid pressure was applied to the anterior cricoid by an attending anesthesiologist. In addition, the effect of posterior cervical support was tested during the trials. The amount of angular and linear motion between C5 and C6 was measured using a Fastrak, three-dimensional, electromagnetic motion analysis device (Polhemus Inc., Colchester, VT).
  
  
  RESULTS
  When cricoid pressure is applied, the largest angular motion was 3 degrees and occurred in flexion-extension at C5-C6. The largest linear displacement was 1.36 mm and was in anterior-posterior displacement of C5-C6. When manual posterior cervical support was applied, the flexion-extension was improved to less than half this value (1.43 degrees), and this reached statistical significance (p = 0.001). No other differences were observed to be significant in the other planes of motion with the applications of support.
  
  
  CONCLUSIONS
  Based on the evidence presented, we believe that the application of cricoid pressure to a patient with a globally unstable subaxial cervical spine injury causes small displacements. There may be some benefit to the use of manual posterior cervical spine support for reducing motion at such an injured segment.
authors.affiliation: Department of Orthopaedic Surgery, University of Texas, Houston, Texas.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Prasarn
authors.affiliation: Department of Orthopaedic Surgery, University of Florida, Gainesville, Florida.
authors.forename: MaryBeth
authors.initials: M
authors.lastname: Horodyski
authors.affiliation: Department of Orthopaedic Surgery, University of Texas, Houston, Texas.
authors.forename: Prism
authors.initials: P
authors.lastname: Schneider
authors.affiliation: Department of Anesthesiology, University of Florida, Gainesville, Florida.
authors.forename: Adam
authors.initials: A
authors.lastname: Wendling
authors.affiliation: Department of Anesthesiology, University of Texas, Houston, Texas.
authors.forename: Carin A
authors.initials: CA
authors.lastname: Hagberg
authors.affiliation: Department of Orthopaedic Surgery, Veterans Affairs Hospital, Asheville, North Carolina.
authors.forename: Glenn R
authors.initials: GR
authors.lastname: Rechtine
mesh_terms: D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D002574:Cervical Vertebrae / Q000293:injuries* / Q000503:physiopathology; D003413:Cricoid Cartilage / Q000502:physiology*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D019838:Neck Injuries / Q000503:physiopathology*; D011312:Pressure / Q000009:adverse effects*; D016059:Range of Motion, Articular / Q000502:physiology; D013124:Spinal Injuries / Q000503:physiopathology*
keywords: airway; aspiration; cervical spine; cricoid pressure; injury