Lecture 13

Question 1

What are the potential causes of spinal trauma?

Answer 1

*external:
-hit by car
-falls
-falling objects
-projectiles

*internal:
-intervertebral disc dz
-pathologic fractures
-vascular

Question 2

What are the primary trauma-induced injuries that affect the spinal cord?

Answer 2

-concussion
-compression
-spinal cord contusion (damage to blood vessels in spinal cord parenchyma)
-fracture/luxation
-hemorrhage

Question 3

What are the secondary trauma-induced injuries that affect the spinal cord (24-48 hours after primary injury)?

Answer 3

-excitotoxicity
-impaired autoregulation/ischemia
-accumulation of intracellular calcium
-oxidative injury
-inflammation
-apoptosis

Question 4

Which aspects of triage are most important to assess from a neurologic standpoint?

Answer 4

-spinal cord injury
-fracture/luxation

Question 5

What should be done when assessing a possible spinal cord trauma patient?

Answer 5

-be aware of potential spinal instability and limit manipulation
-assess nociception and deep pain before giving analgesics or sedating

Question 6

What should be done first when triaging a trauma case?

Answer 6

-assess vital parameters
-perform auscultation
-measure blood pressure
-AFAST and TFAST
-SpO2 and PaO2/PaCO2 monitoring

Question 7

What blood pressure values fall under hypotension and increase risk for secondary spinal cord injury?

Answer 7

-systolic BP < 90 mmHg
-MAP < 80 mmHg

Question 8

What are the target values for PaO2 and PaCO2 to ensure appropriate oxygenation to brain/nervous system?

Answer 8

-PaO2 > 90 mmHg in dogs
-PaO2 > 100 mmHg in cats
-PaCO2 between 35 and 45 mmHg

Question 9

What is the second step in assessing a trauma patient?

Answer 9

-stabilize to prevent further injury at fracture site/suspect fracture site
-assess neuro. status to best of ability; MUST assess deep pain at the very least

Question 10

Why is deep pain the most important aspect of a neuro. exam on trauma patients?

Answer 10

if deep pain is absent, the patient’s prognosis for return to normal function is poor

Question 11

What are the characteristics of cervical fractures?

Answer 11

-lesions/fractures at C5, C6, and C7 are important for patient prognosis
-phrenic nerve innervating diaphragm arises from C5 to C7 cervical nerves
-damage to phrenic nerve can cause patient to be dyspneic/have difficulty breathing

Question 12

What are the signs of a patient with phrenic nerve deficits?

Answer 12

-decreased movement of chest wall
-abdominal breathing with no thoracic component

Question 13

What is the third step in assessing a trauma patient?

Answer 13

pain control once neuro/deep pain assessment is complete

Question 14

What are the characteristics of Schiff-Sherrington posture?

Answer 14

-occurs with acute thoracolumbar (typically T3-L3) lesions
-damages ascending interneurons from L1-L5
-decreases extensor inhibition
-get persistent thoracic limb extension with normal thoracic limb gait
-does NOT predict prognosis

Question 15

What are the characteristics of spinal shock?

Answer 15

-transient loss of muscle tone and reflexes caudal to lesion
-can cause patient to mimic L4-S3 lesion when lesion is truly T3-L3
-resolves within 30 minutes to 48 hours
-complicates lesion localization

Question 16

What are the characteristics of radiographs as a diagnostic for spinal trauma?

Answer 16

-thoracic rads, survey rads, and spinal rads typically performed
-lateral views okay to perform
-VD view should be taken with horizontal beam; do NOT place patient on back
-fairly good sensitivity at recognizing subluxations and fractures
-okay sensitivity at detecting fragments in spinal canal (compared to CT)
-avoid sedation if possible; can cause relaxation and instability of fractures

Question 17

What are the pros of MRI imaging for spinal fractures?

Answer 17

-can identify intramedullary changes
-extra-medullary compression and disruption to CSF flow is noticeable
-able to evaluate adjacent soft tissue structures

Question 18

What are the cons of MRI imaging for spinal fractures?

Answer 18

-inferior evaluation of bony structures compared to CT
-thicker slices compared to CT; may overlook structural issues
-longer time of acquisition
-requires general anesthesia

Question 19

What are the characteristics of CT imaging for spinal fractures?

Answer 19

-allows superior recognition of bony defects
-small slice thickness allows for detailed evaluation of entire anatomy
-good modality for evaluating acute hemorrhage
-superior method for vertebral trauma eval.; sensitivity of up to 100%
-minor sedation only

Question 20

What are important things to consider when using imaging in spinal trauma cases?

Answer 20

-sedation causes relaxation and can lead to destabilization
-radiographs will underestimate actual displacement
-images show where vertebrae are now; not where there were during injury

Question 21

What are the characteristics of vertebral fracture and luxation?

Answer 21

-most commonly caused by flexion of spinal column
-results from disruption of dorsal and ventral stabilizing ligamentous structures
-caudal segment displaces ventrally in dogs
-caudal segment displaces dorsally in cats

Question 22

What is the fracture etiopathogenesis?

Answer 22

flexion

Question 23

What is the fracture etiopathogensis?

Answer 23

extension

Question 24

What is the fracture etiopathogenesis?

Answer 24

compression

Question 25

Where are spinal fractures most commonly located?

Answer 25

50%: between T11 and L6 30%: lumbosacral 20%: cervical

Question 26

Which systemic injuries are T11-L6 fractures commonly associated with?

Answer 26

-pneumothorax -pulmonary contusions -orthopedic injuries -urogenital injuries -diaphragmatic hernia

Question 27

What is the prognosis for spinal cord injury/trauma?

Answer 27

-absence of nociception yields guarded to poor prognosis for return to function -good prognosis if pain perception is intact to tail and digits -perineal sensation being intact in lower lumbar/sacral fractures indicates patient will remain continent -some deep pain negative animals may become spinal walkers -severity of displacement does not determine prognosis on its own

Question 28

What are spinal walkers?

Answer 28

-animals that ambulate with a strictly reflexive gait -no urinary or fecal continence -cannot occur with L4-S3 lesions

Question 29

What are the goals of surgical or medical treatment for spinal injury/trauma?

Answer 29

-prevent further damage to neuronal structures -decompress spinal cord

Question 30

How is a patient determined to be a surgical candidate vs medical management candidate in spinal trauma cases?

Answer 30

-stability of fracture -progression of signs -pain -neurological deficits

Question 31

What are the components of the vertebrae that fall into the dorsal compartment in the three compartment theory?

Answer 31

-articular processes -laminae -pedicles -spinous processes -interarcuate and interspinous ligaments

Question 32

What are the components of the vertebrae that fall into the middle compartment in the three compartment theory?

Answer 32

-dorsal longitudinal ligament -dorsal annulus -dorsal vertebral body

Question 33

What are the components of the vertebrae that fall into the ventral compartment in the three compartment theory?

Answer 33

-remaining vertebral body -lateral and ventral annulus -nucleus pulposus -ventral longitudinal ligament

Question 34

In the three compartment theory, which patients require surgery?

Answer 34

-two compartments compromised -ventral compartment compromised alone -compression of spinal cord present -animal is not amenable to medical management

Question 35

Why is surgery the preferred treatment for spinal trauma?

Answer 35

more rapid and more complete neurologic recovery

Question 36

What are the components of medical management for spinal trauma patients?

Answer 36

-cage rest for at least 8 weeks -external coaptation -nursing care to keep bandages/brace in proper order -best for small dogs and cats

Question 37

What are the pros and cons of surgical management for spinal trauma?

Answer 37

Pros: -open reduction -strong fixation -decompression of spine -faster and more complete recovery Cons: -cost -risk of infection -need for specialist -patient must still undergo cage rest

Question 38

Which decompression techniques are used in spinal trauma surgery?

Answer 38

-hemilaminectomy -dorsal laminectomy -partial corpectomy