Motion of a Cadaver Model of Cervical Injury During Endotracheal Intubation With a Bullard Laryngoscope or a Macintosh Blade With and Without In-line Stabilization

Turner, Christopher R.; Block, Jessica L.; Shanks, Amy; Morris, Michelle; Lodhia, Keith R.; Gujar, Sachin K.

doi:10.1097/ta.0b013e318182afa8

Cited by 20 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…39 In fact, at the C3-4 and C4-5 segments, extension of injured cadaver segments during intubation did not seem to exceed the extension observed during intubation of patients with stable cervical spines. 9 Similarly, in 5 of 7 cadaveric studies, 7,15,16,34 subluxation of injured segments during intubation also did not appear to exceed physiologically normal patient values. However, 2 of 7 cadaveric studies found marked (pathological) segmental subluxation during intubation in the presence of severe C5-6 injury (4.8 mm [Donaldson et al 6 ] and 5.7 mm [Prasarn et al 22 ]).…”

Section: Limitations and Implications Of Previous Cadaveric Intubatiomentioning

confidence: 75%

“…19,30 Of particular relevance to our study is that intact (stable) C3-4 extension during Macintosh intubation in cadavers was less than C3-4 extension previously observed in living patients (0.3° ± 3.0° vs 5.1° ± 3.7°, respectively), despite the application of equivalent intubation forces. Of the 6 previous cadaver intubation studies in which the motion of surgically injured subaxial segments during intubation was examined 6,7,15,16,22,34 (see Table 3), only 1 study measured motion of the segment of interest during intubation in the intact state before injury creation. 15 Specifically, Lennarson et al 15 reported a median baseline (intact) C4-5 extension of 0.8° with Macintosh intubation, a value that seems to be less than the C4-5 extension observed in living patients (2.5° ± 3.5°; 9 1.8° ± 3.6°1 4 ).…”

Section: Limitations and Implications Of Previous Cadaveric Intubatiomentioning

confidence: 99%

“…8 These factors, either singly or collectively, might result in intubation motion-force characteristics (biomechanics) that differ substantively among cadaveric studies and, more importantly, differ from those of living patients. Table 3 summarizes all previous cadaver intubation studies in which the motion of injured subaxial cervical spine segments were characterized during direct laryn-goscopy, 6,7,15,16,22,34 including data from this study. In none of these 7 cadaveric studies did intervertebral angulation (either flexion or extension) of unstable segments seem to exceed physiologically normal patient values.…”

Section: Limitations and Implications Of Previous Cadaveric Intubatiomentioning

confidence: 99%

See 2 more Smart Citations

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

Hindman

Fontes

From

et al. 2016

SPI

View full text Add to dashboard Cite

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.

show abstract

Section: Limitations and Implications Of Previous Cadaveric Intubatiomentioning

confidence: 75%

Section: Limitations and Implications Of Previous Cadaveric Intubatiomentioning

confidence: 99%

Section: Limitations and Implications Of Previous Cadaveric Intubatiomentioning

confidence: 99%

See 1 more Smart Citation

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

Hindman

Fontes

From

et al. 2016

SPI

View full text Add to dashboard Cite

show abstract

“…5 Consequently, manual inline stabilization, which does not utilize axial traction, is the method commonly used to reduce intubation-mediated cervical spine motion. Nevertheless, in two cadaver intubation studies, when compared with conventional laryngoscopy, manual inline stabilization did not change the motion of unstable cervical segments, 6,7 and in one study, it increased pathologic motion (subluxation). 5 Increased pathologic motion with manual in-line stabilization is most likely explained as follows: first, by decreasing cervical spine motion, this technique impairs glottic visualization 8,9 ; second, when glottic visualization is impaired, anesthesiologists may apply greater laryngoscope force, either with 9 or without manual in-line stabilization 10 ; and third, in the presence of an unstable segment, greater laryngoscope force application may result in greater segmental motion.…”

Section: To the Editormentioning

confidence: 88%

Cervical Injury after Videolaryngoscopy in Patient with Ankylosing Spondylitis: Comment

Hindman

Dexter²

2021

Anesthesiology

View full text Add to dashboard Cite

T he recent article by Epaud et al. 1 reinforces the need for anesthesiologists to be comfortable with the flexible fiberoptic intubation technique. I read with great concern that a neurologic injury occurred because of the choice of videolaryngoscopy as the intubation approach because the operator was more familiar with that technique. Was the decision to use videolaryngoscopy a result of our anesthesiology training programs shifting the focus of difficult airway training to videolaryngoscopy because this technique is readily available and relatively easy to use compared to flexible fiberoptic intubation? It has been demonstrated that videolaryngoscopy does not significantly reduce cervical spine movement compared to direct laryngoscopy 2 and, unfortunately, patient harm occurred in the authors' case presentation.The authors endorse that flexible fiberoptic intubation could have been used to avoid injury; the use of fiberoptic intubation mitigates cervical spine movement because it is flexible and can be manipulated in difficult anatomy presentations. A randomized clinical trial showed that there was no difference in intubation time and success rate 3 between videolaryngoscopy and flexible fiberoptic intubation in experienced hands. That is the key: experience! Anesthesiology residency programs should not compromise training in flexible fiberoptic intubation because of the relative ease of use and convenience of videolaryngoscopy, and American Board of Anesthesiology/Accreditation Council for Graduate Medical Education requirements should reflect this.

show abstract

“…This is consistent with in vitro preconditioning effects. Therefore, we suggest prior cadaver intubation studies which have utilized repeated intubations (4–6 intubations, 9,10,12,15 9–16 intubations, 11,13 or 52 intubations 14 ), but that have not controlled for serial changes in laryngoscope force and/or cervical spine motion, may not accurately predict cervical spine motion.…”

Section: Discussionmentioning

confidence: 99%

Intubation Biomechanics

et al. 2015

View full text Add to dashboard Cite

Introduction The aims of this study were to characterize: 1) cadaver intubation biomechanics, including the effect of repeated intubations; and 2) the relationship between intubation force and the motion of an injured cervical segment. Methods Fourteen cadavers were serially intubated using force-sensing Macintosh and Airtraq laryngoscopes in random order, with simultaneous cervical spine motion recorded with lateral fluoroscopy. Motion of the C1-C2 segment was measured in the intact and injured state (Type II odontoid fracture). Injured C1-C2 motion was proportionately corrected for changes in intubation forces that occurred with repeated intubations. Results Cadaver intubation biomechanics were comparable to those of patients in all parameters other than C2-C5 extension. In cadavers, intubation force (Set 2/Set1 force ratio = 0.61 [95% CI: 0.46, 0.81]; P=0.002) and Oc-C5 extension (Set 2 –Set 1 difference = −6.1 degrees [95% CI: −11.4, −0.9]; P=0.025) decreased with repeated intubations. In cadavers, C1-C2 extension did not differ: 1) between intact and injured states; or 2) in the injured state, between laryngoscopes (with and without force correction). With force correction, in the injured state, C1-C2 subluxation was greater with the Airtraq (mean difference 2.8 mm [95% CI: 0.7, 4.9 mm]; P=0.004). Discussion With limitations, cadavers may be clinically relevant models of intubation biomechanics and cervical spine motion. In the setting of a Type II odontoid fracture, C1-C2 motion during intubation with either the Macintosh or Airtraq does not appear to greatly exceed physiologic values or to have a high likelihood of hyperextension or direct cord compression.

show abstract

Motion of a Cadaver Model of Cervical Injury During Endotracheal Intubation With a Bullard Laryngoscope or a Macintosh Blade With and Without In-line Stabilization

Abstract: We were unable to demonstrate any significant effect of MILS on the motion of an unstable cervical spine in this cadaver model. The BL appears to be a viable alternative to DL in the setting of an unstable lower cervical spine.

Cited by 20 publications

References 21 publications

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

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

Cervical Injury after Videolaryngoscopy in Patient with Ankylosing Spondylitis: Comment

Intubation Biomechanics

Contact Info

Product

Resources

About