Intubation Biomechanics: Clinical Implications of Computational Modeling of Intervertebral Motion and Spinal Cord Strain during Tracheal Intubation in an Intact Cervical Spine

2021 ◽  
Author(s):  
Benjamin C. Gadomski ◽  
Bradley J. Hindman ◽  
Mitchell I. Page ◽  
Franklin Dexter ◽  
Christian M. Puttlitz
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Tracheal Intubation ◽  
Cervical Spinal Cord ◽  
Maximum Force ◽  
Cervical Cord ◽  
Injury Threshold ◽  
Force Magnitude ◽  
Cord Injury ◽  
Cervical Motion

Background In a closed claims study, most patients experiencing cervical spinal cord injury had stable cervical spines. This raises two questions. First, in the presence of an intact (stable) cervical spine, are there tracheal intubation conditions in which cervical intervertebral motions exceed physiologically normal maximum values? Second, with an intact spine, are there tracheal intubation conditions in which potentially injurious cervical cord strains can occur? Methods This study utilized a computational model of the cervical spine and cord to predict intervertebral motions (rotation, translation) and cord strains (stretch, compression). Routine (Macintosh) intubation force conditions were defined by a specific application location (mid-C3 vertebral body), magnitude (48.8 N), and direction (70 degrees). A total of 48 intubation conditions were modeled: all combinations of 4 force locations (cephalad and caudad of routine), 4 magnitudes (50 to 200% of routine), and 3 directions (50, 70, and 90 degrees). Modeled maximum intervertebral motions were compared to motions reported in previous clinical studies of the range of voluntary cervical motion. Modeled peak cord strains were compared to potential strain injury thresholds. Results Modeled maximum intervertebral motions occurred with maximum force magnitude (97.6 N) and did not differ from physiologically normal maximum motion values. Peak tensile cord strains (stretch) did not exceed the potential injury threshold (0.14) in any of the 48 force conditions. Peak compressive strains exceeded the potential injury threshold (–0.20) in 3 of 48 conditions, all with maximum force magnitude applied in a nonroutine location. Conclusions With an intact cervical spine, even with application of twice the routine value of force magnitude, intervertebral motions during intubation did not exceed physiologically normal maximum values. However, under nonroutine high-force conditions, compressive strains exceeded potentially injurious values. In patients whose cords have less than normal tolerance to acute strain, compressive strains occurring with routine intubation forces may reach potentially injurious values. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Numerical Investigation of Spinal Cord Injury After Flexion-Distraction Injuries At the Cervical Spine

2021 ◽  
Author(s):  
Marie-Helene Beausejour ◽  
Eric Wagnac ◽  
Pierre-Jean Arnoux ◽  
Jean-Marc Mac-Thiong ◽  
Yvan Petit
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spine ◽  
White Matter ◽  
Cervical Spinal Cord ◽  
Element Model ◽  
Von Mises Stress ◽  
Study Objective ◽  
Cord Injury ◽  
Post Traumatic

Abstract Flexion-distraction injuries frequently cause traumatic cervical spinal cord injury (SCI). Post-traumatic instability can cause aggravation of the secondary SCI during patient's care. However, there is little information on how the pattern of disco-ligamentous injury affects the SCI severity and mechanism. This study objective was to analyze how different flexion-distraction disco-ligamentous injuries affect the SCI mechanisms during post-traumatic flexion and extension. A cervical spine finite element model including the spinal cord was used and different combinations of partial or complete intervertebral disc (IVD) rupture and disruption of various posterior ligaments were modeled at C4-C5, C5-C6 or C6-C7. In flexion, complete IVD rupture combined with posterior ligamentous complex rupture was the most severe injury leading to the most extreme von Mises stress (47 to 66 kPa), principal strains p1 (0.32 to 0.41 in white matter) and p3 (-0.78 to -0.96 in white matter) in the spinal cord and to the most important spinal cord compression (35 to 48 %). The main post-trauma SCI mechanism was identified as compression of the anterior white matter at the injured level combined with distraction of the posterior spinal cord during flexion. There was also a concentration of the maximum stresses in the gray matter after injury. Finally, in extension, the injuries tested had little impact on the spinal cord. The capsular ligament was the most important structure in protecting the spinal cord. Its status should be carefully examined during patient's management.

scholarly journals Transcutaneous spinal cord stimulation of the cervical cord modulates lumbar networks

2020 ◽  
Vol 123 (1) ◽  
pp. 158-166 ◽  
Author(s):  
Trevor S. Barss ◽  
Behdad Parhizi ◽  
Vivian K. Mushahwar
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Cervical Spinal Cord ◽  
H Reflex ◽  
Cervical Cord ◽  
Arm Cycling ◽  
Cord Injury ◽  
Walking Capacity ◽  
Transcutaneous Spinal Cord Stimulation ◽  
Lumbar Cord

It has been established that coordinated arm and leg (A&L) cycling facilitates corticospinal drive and modulation of cervico-lumbar connectivity and ultimately improves overground walking in people with incomplete spinal cord injury or stroke. This study examined the effect of noninvasive transcutaneous spinal cord stimulation (tSCS) on the modulation of cervico-lumbar connectivity. Thirteen neurologically intact adults participated in the study. The excitability of the Hoffmann (H) reflex elicited in the soleus muscle was examined under multiple conditions involving either the arms held in a static position or rhythmic arm cycling while tSCS was applied to either the cervical or lumbar cord. As expected, soleus H-reflex amplitude was significantly suppressed by 19.2% during arm cycling (without tSCS) relative to arms static (without tSCS). Interestingly, tSCS of the cervical cord with arms static significantly suppressed the soleus H-reflex (−22.9%), whereas tSCS over the lumbar cord did not suppress the soleus H-reflex (−3.8%). The combination of arm cycling with cervical or lumbar tSCS did not yield additional suppression of the soleus H-reflex beyond that obtained with arm cycling alone or cervical tSCS alone. The results demonstrate that activation of the cervical spinal cord through both rhythmic arm cycling and tonic tSCS significantly modulates the activity of lumbar networks. This highlights the potential for engaging cervical spinal cord networks through tSCS during rehabilitation interventions to enhance cervico-lumbar connectivity. This connectivity is influential in facilitating improvements in walking function after neurological impairment. NEW & NOTEWORTHY This is the first study to investigate the modulatory effects of transcutaneous spinal cord stimulation (tSCS) on cervico-lumbar connectivity. We report that both rhythmic activation of the cervical spinal cord through arm cycling and tonic activation of the cervical cord through tSCS significantly modulate the activity of lumbar networks. This suggests that engaging cervical spinal cord networks through tSCS during locomotor retraining interventions may not only enhance cervico-lumbar connectivity but also further improve walking capacity.

scholarly journals Buspirone Dose-Response on Facilitating Forelimb Functional Recovery in Cervical Spinal Cord Injured Rats

Dose-Response ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 155932582199813
Author(s):  
Rakib Uddin Ahmed ◽  
V. Reggie Edgerton ◽  
Shuai Li ◽  
Yong-Ping Zheng ◽  
Monzurul Alam
Keyword(s):  
Spinal Cord ◽  
Grip Strength ◽  
Dose Response ◽  
Cervical Spinal Cord ◽  
Dose Dependence ◽  
Dorsal Column ◽  
Cervical Cord ◽  
Sprague Dawley ◽  
Post Injury ◽  
Cord Injury

Buspirone, widely used as a neuropsychiatric drug, has also shown potentials for motor function recovery of injured spinal cord. However, the optimum dosages of such treatment remain unclear. In this study, we investigated the dose-response of Buspirone treatment on reaching and grasping function in cervical cord injured rats. Seventeen adult Sprague-Dawley rats were trained to reach and grasp sugar pellets before a C4 bilateral dorsal column crush injury. After 1 week post-injury, the rats were divided into 3 groups to receive 1 of 3 different dosages of Buspirone (i.p., 1 dose/day: 1.5, n = 5; 2.5, n = 6 and 3.5 mg/kg b.w., n = 6). Forelimb reaching and grip strength test were recorded once per week, within 1 hour of Buspirone administration for 11 weeks post-injury. Different dose groups began to exhibit differences in reaching scores from 4 weeks post-injury. From 4-11 weeks post-injury, the reaching scores were highest in the lowest-dose group rats compared to the other 2 dose groups rats. Average grip strength was also found higher in the lowest-dose rats. Our results demonstrate a significant dose-dependence of Buspirone on the recovery of forelimb motor functions after cervical cord injury with the best performance occurring at the lowest dose tested.

Case report of ervical myelopathy due to ossification of the posterior longitudinal ligament in association with flavum ligament ossification: MRI and CT appearance

2013 ◽  
Vol 20 (2) ◽  
pp. 79-83
Author(s):  
Monique Boukobza ◽  
Jurgita Ušinskienė ◽  
Simona Letautienė
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Double Layer ◽  
Spinal Canal ◽  
Mixed Type ◽  
Cervical Spinal Cord ◽  
Asian Population ◽  
Posterior Longitudinal Ligament ◽  
Cord Compression ◽  
Cord Injury

Background. Our objective is to analyze the cervical spinal cord damage and spinal canal stenosis due to OPLL which usually affects the cervical spine and leads to progressive myelopathy in 50–60s in Asian population; to demonstrate the mixed type OPLL and to show OPLL specific dural penetration signs: “double- layer” and “C-sign” on imaging. Materials and methods. Subacute cord compression developed over a 3-month period in a 43-year-old Japanese patient. Severe spinal canal narrowing was related to the mixed type OPLL at C3–C4 through C6–C7 associated to flavum ligament ossification at T3–T4. Lateral radiograph of the cervical spine showed intraspinal ossification, CT demonstrated specific dural penetration signs, and MRI disclosed spinal cord compression. Laminectomy at C3–C7 was performed and decompression of the spinal cord was confirmed by postoperative MRI. Conclusions. Absolute cervical stenosis and association with other diseases (like calcification of flavum ligament) predispose the patient to develop more severe deficit earlier in the clinical course. Specific CT signs, “double-layer” and “C-sign”, show dural involvement. MRI is a very useful modality to identify the precise level and extent of the spinal cord injury. OPLL must be included in the differential diagnosis of subacute cervical myelopathy.

scholarly journals Cervical Spinal Cord, Root, and Bony Spine Injuries

2011 ◽  
Vol 114 (4) ◽  
pp. 782-795 ◽  
Author(s):  
Bradley J. Hindman ◽  
John P. Palecek ◽  
Karen L. Posner ◽  
Vincent C. Traynelis ◽  
Lorri A. Lee ◽  
...  
Keyword(s):  
Cervical Spine ◽  
General Anesthesia ◽  
Cervical Spinal Cord ◽  
Traumatic Injury ◽  
Cervical Cord ◽  
Cervical Injury ◽  
Claims Database ◽  
Cord Injury ◽  
Spine Injuries ◽  
Closed Claims

Background The aim of this study was to characterize cervical cord, root, and bony spine claims in the American Society of Anesthesiologists Closed Claims database to formulate hypotheses regarding mechanisms of injury. Methods All general anesthesia claims (1970-2007) in the Closed Claims database were searched to identify cervical injuries. Three independent teams, each consisting of an anesthesiologist and neurosurgeon, used a standardized review form to extract data from claim summaries and judge probable contributors to injury. Results Cervical injury claims (n = 48; mean ± SD age 47 ± 15 yr; 73% male) comprised less than 1% of all general anesthesia claims. When compared with other general anesthesia claims (19%), cervical injury claims were more often permanent and disabling (69%; P < 0.001). In addition, cord injuries (n = 37) were more severe than root and/or bony spine injuries (n = 10; P < 0.001), typically resulting in quadriplegia. Although anatomic abnormalities (e.g., cervical stenosis) were often present, cord injuries usually occurred in the absence of traumatic injury (81%) or cervical spine instability (76%). Cord injury occurred with cervical spine (65%) and noncervical spine (35%) procedures. Twenty-four percent of cord injuries were associated with the sitting position. Probable contributors to cord injury included anatomic abnormalities (81%), direct surgical complications (24% [38%, cervical spine procedures]), preprocedural symptomatic cord injury (19%), intraoperative head/neck position (19%), and airway management (11%). Conclusion Most cervical cord injuries occurred in the absence of traumatic injury, instability, and airway difficulties. Cervical spine procedures and/or sitting procedures appear to predominate. In the absence of instability, cervical spondylosis was the most common factor associated with cord injury.

scholarly journals Traumatic cervical spinal cord injury with "negative" cervical spine CT scan

2010 ◽  
Vol 2010 (mar04 1) ◽  
pp. bcr1220092525-bcr1220092525 ◽  
Author(s):  
S. Kolli ◽  
A. Schreiber ◽  
J. Harrop ◽  
J. Jallo
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cervical Spine ◽  
Ct Scan ◽  
Cervical Spinal Cord ◽  
Cervical Spinal Cord Injury ◽  
Spine Ct ◽  
Cord Injury

scholarly journals Torg’s ratio in normal adult nepalese population

2017 ◽  
Vol 18 (1) ◽  
pp. 5-9
Author(s):  
Badri Rijal ◽  
R K Pokharel ◽  
S Paudel ◽  
L L Shah
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Spinal Stenosis ◽  
Spinal Canal ◽  
Cervical Spinal Cord ◽  
Canal Stenosis ◽  
Cervical Spinal Canal ◽  
Cord Injury ◽  
History Of ◽  
Cervical Spinal Stenosis

Introduction: Acute cervical trauma occasionally leads to cervical canal stenosis in some individuals in spite of minor trauma. The spinal canal-to-vertebral body ratio (Torg-Pavlov ratio) has been proposed for assessing developmental spinal canal stenosis. It is not affected by magnification, and is measured on lateral plain films of cervical vertebrae. The result of this study may help in better understanding of the Torg’s ratio, which is more reliable than direct measuring of the mid-sagittal diameter of the cervical spinal canal in the diagnosis of cervical spinal stenosis or predicting the prognosis of cervical spinal cord injury. If Torg’s ratio is below normal there is risk of cervical cord injury whereas relatively safe in large Torg’s ratio. Torg’s ratio can be accessed even in rural areas where x-rays are easily available and more economical than MRI and CT scan. It can assess the risk of cord injury during sports and outdoor activities and help individuals’ choose safe carrier in sports or others activities.Methods: In order to ascertain the normal values of the Torg’s ratio in adults Nepalese, hundred sets of cervical vertebral columns of hundred adult Nepalese population of age group 20-40 years were examined. Consecutive patients presenting with history of neck pain with normal x-ray findings or history of trauma without cervical spine injury from Orthopaedic OPD (out patients department) and emergency department of Tribhuvan University Teaching Hospital, Maharajgunj, Kathmandu from March 2011 to August 2012 were included in the study.Results: There were 48 males and 52 females with age ranging from 20 yrs to 40 yrs with the mean of 30.34±5.36 years. The normal average canal/body ratio of the cervical spine is 0.99 +/- 0.09 in male and 1.01 +/- 0.07 in female. It was observed that the ratio of the antero-posterior diameters of cervical spinal canal and vertebral bodies showed sexual dimorphism.Conclusion: The Torg’s ratio is the same irrespective of gender and height. The result of this study will help in better understanding of the Torg’s ratio, which is more reliable than direct measuring of the mid-sagittal diameter of the cervical spinal canal in the diagnosis of cervical spinal stenosis or predicting the prognosis of cervical spinal cord injury.JSSN 2015; 18 (1), Page: 5-9

Value of gas myelography in early management of acute cervical spinal cord injuries

1975 ◽  
Vol 42 (3) ◽  
pp. 330-337 ◽  
Author(s):  
Alain B. Rossier ◽  
Jean Berney ◽  
Arthur E. Rosenbaum ◽  
Jurg Hachen
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injuries ◽  
Cervical Spinal Cord ◽  
Cord Compression ◽  
Cervical Cord ◽  
Valuable Contribution ◽  
Early Management ◽  
Specific Patient ◽  
Content Type ◽  
Cord Injury

✓ Gas myelography was carried out in 22 patients with acute cervical spinal cord injuries in whom oily contrast media seemed contraindicated. The authors believe this technique makes a valuable contribution to the basic decision regarding the surgical versus medical treatment of a specific patient with a cervical cord injury. They emphasize the importance of visualizing cord compression due to disc herniation in these cases and conclude that gases are the optimal contrast agents for visualization of the entire circumference of the spinal cord.

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