Chapter 32 Thoracolumbar vertebral column

Question 1

What is referred as the zygapophyseal joint?

Answer 1

The articular process joint

Question 2

Which is typically the anticlinal vertebrae?

Answer 2

T11

Question 3

Where is located the internal vertebral venous plexus?

Answer 3

Along the ventolateral aspect of the vertebral canal

Question 4

List the different approaches to the thoracolumbar vertebral columns

Answer 4

• Dorsal
• Lateral
• Dorsolateral

Question 5

List at least 3 different methods that allow proper identification of the correct vertebrae

Answer 5

Intra-op:
- Palpation of the last rib
- Palpation of the transverse process of L1
- Counting from Sacrum

pre-op
- Use of methylene blue staining

Question 6

Describe the surgical approach to the dorsal thoracolumbar column

Answer 6

• Dorsal approach ca 1-2 cm lateral to the midline
• Incision of SC and thoracolumbar fascia
• Elevation of m. multifidus from the vertebral body
• incision of the m. multifidus tension on the articular process
• If need to extend the approach more ventrally, incision of the longissimus lumborum tendon on the accessory process

Question 7

List the three major portions of the vertebral column that provide stability and that should
be evaluated by the surgeon to warranty surgical stabilisation

Answer 7

• Vertebral body - acts as butress to resist bending and axial loading
• Articular processes - resists all forces
• intervertebral disc - resist rotation and lateral bending

Question 8

List two possible approaches to the thoracolumbar spinal cord

Answer 8

Hemilaminectomy
Dorsal laminectomy

Question 9

Which is the correct name of the misnomer hemilaminectomy?

Answer 9

Hemiarchectomy

Question 10

How do you distinguish between cortical and cancellous bone?

Answer 10

Cortical bone is white while cancellous bone is red

Question 11

Describe the 3 modifications of the dorsal laminectomy named according to the extent of
bone removal

Answer 11

Funkquist A - removal of spinouss process, lamina articular process and ca half of the dorsal portion of the pedicle

Funkquist B - leaved the art. processes and pedicle intact

Deep dorsal laminectomy - removal of the dorsal lamination, the entire zygapophyseal joint tot he lever of the ventral aspect of the vertebral column

Question 12

indicate the correct prognostic ratio in dogs with thoracolumbar IVD
herniation with no proprioception

Answer 12

Length of the intramedullary pattern/length of L2 >=5 in a lateral view has a 26% of
recovery compare to a 61% recovery rate for dogs with ratios <5

Question 13

Describe the characteristics of the MRI sequences with regard to the intensity of disc
material, fat and fluid

Answer 13

T2W - CSF and nondegenerative disk is hyperintense. Degenerative disk is hypointense. Fat is hypointense

T1W - CSF and diskmaterial is hypointense, fat is hyperintense
Disk material can be hyperintense post-contrast

Question 14

What are the biomarkers present in the CSF from the cerebromedullar cistern of dogs with
thoracolumbar IVD herniation that are associated with severe spinal cord injury and failure
to recover ambulation?

Answer 14

Matrix metalloproteinase-9 expression
creatinine kinase activity
protein tau concentration
glutamate concentration
haptoglobin concentration nucleated cell count
and protein concentration

Question 15

What are the 3 strategies of the medical management for thoracolumbar IVD herniation and
what kind of success rates does it have

Answer 15

• Analgesia
• rest
• physiotheraphy

ca 55 %

Question 16

Report the success rates in dogs with thoracolumbar IVD herniation with and without
proprioception

Answer 16

With nociception: 72-100%

without: 43-62%