Vertebral Column Trauma

Question 1

Initial Dx + Tx plan for EVERY traumatic SC injury patient:

Answer 1

1. Assess ER ABCs (the force of their trauma was strong enough to physically disrupt their vertebral column, so expect severe polytrauma)
2. Perform neuro exam w/ animal immobilized in lateral recumbency
3. Administer analgesics once vital parameters stabilized & neuro assessment complete (full mu agonists +/- NSAIDS, benzos, alpha2agonists, ketamine)
4. Temporarily immobilize in lat. recumbency (secure pt. to rigid platform), w/out interfering w/ respiration, and obtain radiographs

33% have cardiothoracic injury, 25% have appendicular fx, 25% have significant ST injuries, 20% have moderate-severe TBI, 15% have UT injuries, 10-15% have other abd. injuries

Question 2

What are you trying to determine with radiographs in the traumatic SCI patient?

Answer 2

If the trauma has resulted in unstable vertebral column injury
- 3 compartment model (dorsal, middle, ventral): disruption of 2/3 = instability

1. Dorsal compartment- spinous processes, vertebral laminae, articular processes,
   vertebral pedicles, and dorsal ligamentous complex (supraspinous ligament,
   interspinous ligament, joint capsule, and ligamentum flavum)
2. Middle compartment- dorsal longitudinal ligament, the dorsal annulus fibrosus, and
   the dorsal vertebral body; essentially the floor of the vertebral canal.
3. Ventral compartment- the remainder of the vertebral body, the lateral and ventral
   aspects of the annulus fibrosus, the nucleus pulposus, and the ventral longitudinal
   ligament.

Question 3

When should you assign a Modified Frankel Score (MFS, 0-5) in the traumatic SCI patient? What is the scoring for thoracic-caudal?

Answer 3

• Carefully perform ONLY if the animal is ambulatory; avoid manipulation/palpation of vertebral column + avoid excessive manipulation of the animal

Thoracic-Caudal (T3-caudal) scoring:
- Grade 0 = Normal
- Grade 1 = Pain only
- Grade 2 = Ambulatory paraparesis, ataxia
- Grade 3 = Non-ambulatory paraparesis
- Grade 4 = Paraplegia and DP(+)
- Grade 5 = Paraplegia and DP(-)

Question 4

Prognosis for T3-L3 and L4-S2 TSCI with an MFS grade 4 or better:

Answer 4

• With Sx = 75-80% good
• Conservative mgmt = 60% good

Surgical tx results in faster/more complete neurological recoveries

Question 5

Prognosis for cervical or thoracolumbar TSCI with an MFS grade 5:

Answer 5

Grave/hopeless prognosis for function recovery -> recc. humane euthanasia

Question 6

When is surgical stabilization (internal or external fixation) indicated? Goals?

Answer 6

• Indication: unstable injury plus an MFS Grade 3+
• Goals: reduce the fx or luxation in order to achieve proper anatomical alignment of vertebral column via rigid fixation

ALL unstable injuries require stabilization by either medical or sx tx!

e.g., pins/screws & bone cement

Question 7

When is spinal cord decompression indicated when in addition to surgical tx?

Answer 7

When imaging confirms SC compression (displaced fx fragment; disc rupture; compressive hematoma; penetrating missle)

Question 8

When is conservative/non-surgical management indicated in traumatic SCI patients?

Answer 8

1. Cervical fxx (cervical sx has high morb/mort-40%)
2. Caudal lumbar or lumbosacral fxx w/ MFS grades 1-2
3. No significant concurrent injuries
4. DP(+)

ALL unstable injuries require stabilization by either medical or sx tx!

Cervical vertebral column supports respiratory/cardiac function -> Sx has high risk of irreversibly/fatally interfering with this

Question 9

What should all conservatively managed patients be treated with? How is it applied?

Answer 9

External coaptation (neck/back braces, casts)
- Application: MUST rigidly immobilize high-motion segments ABOVE and BELOW level of injury!!

min. displaced fxx/luxations, MFS grades 1-2, mild concurrent injuries

1. Cervical injury: brace should extend from behind the eyes to behind the shoulders. 2. Thoracolumbar and lumbosacral injuries: brace should extend from in front of the shoulders to behind the pelvic limbs.

v. No attempt should be made to reduce the fracture or luxation prior to or after placing the brace, and the brace should not be expected to result in significant reduction of the fracture or luxation (although sometimes this is observed).

vi. Complications associated with neck and back braces: Bandage soiling requiring replacement; Urine scald and decubital ulcers; Interference with eating or respiration; Intolerable in some animals (esp. cats)

vii. Advantages of neck and back braces: less invasive/expensive; recheck exams at least weekly

Question 10

Sacrocaudal Luxation

Answer 10

“Tail Pull” injury (cats > dogs)
- traction/avulsion trauma to S1-S3 segments/cauda equina

plantigrade stance, flaccid tail, u/d incontinence, absent anal tone

Question 11

How does the prognosis for sacrocaudal luxations differ from other vertebral fractures?

Answer 11

• 75-100% of DP(+) cats will have urinary function return
• 90% of DP(+) cats will have tail function improve/return
• 50-60% of DP(-) cats will have u/d function return
• 15% of DP(-) cats will have tail function return
• > 30 days of DP(-) cats = poor prognostic indicator

Question 12

Complications with conservative tx

Answer 12

• tx failure (persistent instability & pain)
• Coaptation complications (infection, decubitus, inadvertent removal)

Question 13

Complications w/ surgical tx

Answer 13

• Early/acute post op: surgeon technical errors; damage to SC during reduction; effects of concurrent injury
• Late post op: implant failure; implant infection

Question 14

What is the top stress riser region in the SC?

Answer 14

Lumbo-sacral junction (» thoraco-lumbar junction & craniocervical junction)