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.

Keywords: airway; aspiration; cervical spine; cricoid pressure; injury.