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

Bradley J Hindman; Ricardo B Fontes; Robert P From; Vincent C Traynelis; Michael M Todd; Christian M Puttlitz; Brandon G Santoni

doi:10.3171/2016.3.SPINE1640

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

Journal article

Open access

Peer reviewed

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

Bradley J Hindman, Ricardo B Fontes, Robert P From, Vincent C Traynelis, Michael M Todd, Christian M Puttlitz and Brandon G Santoni

Journal of neurosurgery. Spine, Vol.25(5), pp.545-555

11/2016

DOI: 10.3171/2016.3.SPINE1640

PMID: 27231810

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Abstract

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

Motion

Laryngoscopy - methods

Laryngoscopes

Cervical Vertebrae - injuries

Humans

Middle Aged

Male

Fluoroscopy

Intubation, Intratracheal - methods

Biomechanical Phenomena

Aged, 80 and over

Female

Intubation, Intratracheal - adverse effects

Cervical Vertebrae - physiopathology

Laryngoscopy - adverse effects

Cadaver

Supine Position

Details

Title: Subtitle: Intubation biomechanics: laryngoscope force and cervical spine motion during intubation in cadavers-effect of severe distractive-flexion injury on C3-4 motion
Creators: Bradley J Hindman - Department of Anesthesia, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
Ricardo B Fontes - Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
Robert P From - Department of Anesthesia, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
Vincent C Traynelis - Department of Neurosurgery, Rush University Medical Center, Chicago, Illinois
Michael M Todd - Department of Anesthesia, University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
Christian M Puttlitz - Department of Mechanical Engineering, School of Biomedical Engineering, Orthopaedic Bioengineering Research Laboratory, Colorado State University, Fort Collins, Colorado; and
Brandon G Santoni - Foundation for Orthopaedic Research and Education, Tampa, Florida
Resource Type: Journal article
Publication Details: Journal of neurosurgery. Spine, Vol.25(5), pp.545-555
DOI: 10.3171/2016.3.SPINE1640
PMID: 27231810
NLM abbreviation: J Neurosurg Spine
ISSN: 1547-5654
eISSN: 1547-5646
Publisher: American Association of Neurological Surgeons; United States
Language: English
Date published: 11/2016
Academic Unit: Anesthesia
Record Identifier: 9984007161302771

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