Intubation biomechanics: laryngoscope force and cervical spine motion during intubation in cadavers—effect of severe distractive-flexion injury on C3–4 motion

• DOI: 10.3171/2016.3.spine1640
• Publication Date: 2016-05-27T14:01:57Z
• Authors: Bradley J. Hindman; Ricardo B. Fontes; Robert P. From; Vincent C. Traynelis; Michael M. Todd; Christian M. Putt...; Brandon G. Santoni
• Keywords: Laryngoscopes; Subluxation; Biomechanics

OBJECTIVE With application of the forces intubation, injured (unstable) cervical segments may move more than they normally do, which can result in spinal cord injury. The authors tested whether, during endotracheal intervertebral motion an C3–4 segment 1) is greater that intact (stable) state and 2) differs when a high- or low-force laryngoscope used. METHODS Fourteen cadavers underwent 3 intubations using force-sensing laryngoscopes while simultaneous spine was recorded with lateral fluoroscopy. first intubation performed conventional high-force line-of-sight Macintosh laryngoscope. After creation severe distractive-flexion injury, 2 additional were performed, one other indirect video (Airtraq), used random order. RESULTS During intubations, between conditions, extension (0.3° ± 3.0° vs 0.4° 2.7°, respectively; p = 0.9515) anterior-posterior subluxation (−0.1 0.4 mm −0.3 0.6 mm, 0.2754) did not differ. Airtraq segment, despite large difference applied force laryngoscopes, segmental (0.4° 2.7° 0.3° 3.3°, 0.8077) (0.3 0.0 0.7 0.3203) CONCLUSIONS authors' hypotheses regarding relationship confirmed. Motion-force relationships (biomechanics) are predicted by vitro biomechanical behavior isolated segments. limitations inherent to cadaveric studies, results this study suggest all forms injury at risk for pathological intubation.