The effect of airway maneuvers on the unstable C1-C2 segment - A cadaver study

Study Design. This is a cadaver study in which video fluoroscopy is used to measure motion of the unstable spine at C1-C2 during intubation maneuvers. Objectives. To qualify the amount of motion that occurs at an unstable C1-C2 spinal segment during the use of various intubation techniques using a cadaver model, Summary of Background Date. In previous work by the authors, a methodology and measurements for the unstable C5-C6 segment in a cadaver model were developed. These studies showed that the most motion was created by a chin lift and jaw thrust and that oral techniques created more motion than nasal intubation. The potential motion that occurs during intubation with instability al C1-C2 is yet unstudied. Therefore, a study to determine the effects of intubation on the spine with an unstable C1-C2 segment was designed. Methods. Six human cadavers were used for the study. Measurements before and after transoral osteotomy of the odontoid were performed using video fluoroscopy. Pre-intubation maneuvers and oral and nasal intubation were studied. Results. Oral intubation and nasal intubation caused similar diminution of space available for the cord. Chin lift and jaw thrust caused a larger diminution of space available for the cord than either nasal or oral intubation techniques. Conclusions. Although nasal intubation is the accepted procedure for intubation of the unstable spine, nasal and oral intubation seemed to have the same ability to narrow the space available for the cord in the model in this study. Great care should be taken while performing the chin lift/jaw thrust maneuvers in preparation for intubation, because these pre-intubation techniques caused the most motion and hence narrowed the space available for the cord in the unstable cervical spine.