Cervical Spinal Motion during lntubation: Efficacy of Stabilization Maneuvers in the Setting of Complete Segmental Instability

Peter J. Lennarson, MD
Darin Smith, MD
Paul Sawin, MD
Vincent Traynelis, MD
Michael Todd, MD (Iowa City,IA)

Motion of the injured cervical spine during orotracheal intubation is poorly understood. We have previously described a cadaveric model for evaluating cervical spine motion in both the intact and injured states. The current study evaluates the effect of cervical stabilization techniques on spinal motion of the injured subaxial spine. Intubations were performed on IO fresh human cadavers with intact cervical spines and following the creation of a C4–5 complete–ligamentous injury. Movement of the cervical spine during intubation was recorded using video fluoroscopy and examined under the following conditions: 1) no external stabilization, 2) manual in–line cervical immobilization, and 3) Gardner–Wells traction. Subsequently, segmental motion at C4–5 injured level was measured from digitized frames of the recorded video fluoroscopy.

As previously described, the predominant motion at all levels measured in the intact spine was extension, with the greatest degree occurring at the atlanto–occipital junction, followed by the atlanto–axial junction, with progressively less motion at each more caudal level. None of the stabilization techniques significantly altered motion in the subaxial spine.

After complete C4–5 destabilization, the effects of attempted stabilization on distraction, antero–posterior subluxation, and angular rotation were analyzed. Immobilization effectively eliminated distraction, but increased subluxation and angular rotation. Traction increased distraction, but effectively eliminated subluxation and decreased angular rotation. Application of neither stabilization technique had intermediate results with less distraction than traction, less subluxation than immobilization, but increased angular rotation than either technique.

These findings should be considered when treating an injured patient requiring orotracheal intubation.