Auer Ch 51 52 53 Spinal Cord

Front 1

What is the most common signalment for dens fracture with atlantoaxial subluxtion?

Back 1

Foal younger than 6 months of age

Front 2

What is the embryologic origin of the dens?

Back 2

Body of the atlas

Front 3

When does closure of the dens-axis physis close?

Back 3

8-12 months

Front 4

What is the most common location of dens fracture?

Back 4

Cranial physis of the axis which separates the dens from the body of the axis (remains attached to the atlas, axis displaces ventrally)

Front 5

What is the goal of surgery to fix dens fracture?

Back 5

Decompression at fracture site by realignment of the vertebrae and providing stability with fixation

Front 6

What surgical techniques have been described for dens fracture fixation?

Back 6

External fixation with Steinman pins, ventral compression plating with DCP, ventral atlantoaxial fusion with cancellous bone screws, dorsal laminectomy of caudal atlas

Front 7

What is the etiology of atlantoaxial subluxtion without concurrent dens fracture?

Back 7

Congenital or traumatic

Front 8

What is the anatomical result of complete atlantoaxial luxation?

Back 8

Complete disruption of the ligamentous attachment to the dens with displacement of the dens ventral to the atlas

Front 9

Surgical option for atlantoaxial subluxation:

Back 9

subtotal dorsal laminectomy of the caudal 2/3 of the dorsal arch of the atlas, leaving a portion of the dorsal atlantoaxial ligament intact

Front 10

What are the possible sequella of fractures of the ventral arch of the atlas?

Back 10

Healing with a bony callus that impinges the spinal cord, inducing ataxia at a later time frame than the original injury

Front 11

Recent approach to vertical fracture of the axis:

Back 11

reduction of fracture with Steinman pins and bone reduction forceps then plate fixation with a 7 hole narrow 4.5mm DCP on the dorsal rim of the axis with 4.5 mm cortical screws

Front 12

When does caudal cervical vertebral physis closure occur?

Back 12

4-5 years however likely functionally closed around 2 years

Front 13

What can occur with caudal articular process fractures?

Back 13

Pedicle elevates resulting in deroofing of the spinal canal

Front 14

What maintains stability after deroofing of the spinal canal?

Back 14

Dorsal portion of the intervertebral disc

Front 15

What imaging modalities have recently been described for diagnosis of cervical vertebral fracture in the standing horse?

Back 15

Radiography, ultrasonography, nuclear scintigraphy, fluoroscopy

Front 16

What is a possible sequella of caudal cervical vertebral fracture?

Back 16

Worsening of neurologic signs after natural or surgical fusion because of compression at intervertebral sites adjacent to the fusion

Front 17

What are the most common locations for thoracolumbar vertebral body fractures?

Back 17

T1-3, T12, all L

Front 18

What is the most common location for fracture of the dorsal spinous processes?

Back 18

T6

Front 19

Who are candidates for thoracolumbar laminectomy & fracture stabilization?

Back 19

Foals with deep pain recognition or some voluntary movement of the hind limbs

Front 20

What is a minimally invasive approach to dorsal spinous process impingment?

Back 20

Endoscopic subtotal resection of processes and interspinous ligament

Front 21

Where is the anatomical location of the supraspinous bursa?

Back 21

Between the dorsal spinous processes of T2-5 and the nuchal ligament

Front 22

What are the clinical signs of compressive sacral fracture?

Back 22

Neurologic deficits related to manure and urine retention

Front 23

What is the approach to surgical decompression of the sacrum?

Back 23

Removal of spinous processes and dorsal laminae of sacrum

Front 24

Recent approach to sacral fracture fixation in heifers:

Back 24

reduction with strong distraction on dorsal spinous processes with repositioning forceps combined with transrectal pressure. Internal fixation with 4.5 LCP with 5.0 locking screws

Front 25

Back 25

Front 26

Back 26

Front 27

Back 27

Front 28

Back 28

Front 29

How is intravertebral sagittal ratio calculated?

Back 29

Dividing the minimal sagittal diameter of the vertebral canal by the height of the vertebral body

Front 30

How is the minimal sagittal diameter of the vertebral canal obtained?

Back 30

Narrowest diameter measured from the dorsal aspect of vertebral body to the ventral border of the dorsal laminae

Front 31

How is the vertebral body width obtained?

Back 31

Perpendicular to the vertebral canal at the widest point of the cranial aspect of the vertebral body

Front 32

Normal intervertebral sagittal ratio:

Back 32

>52% from C4-C6, >56% at C7 in horses >320 kg

Front 33

What is intervertebral sagittal ratio?

Back 33

Measurement from caudal aspect of dorsal lamina of the vertebral arch to the dorsocranial aspect of the body of the next caudal vertebra divided by the vertebral body width

Front 34

Normal intervertebral sagittal ratio:

Back 34

>0.485

Front 35

Classifications of sagittal ratios:

Back 35

low (<48% at C4-C6), moderate sagittal ration (48%-56%), high (>56%)

Front 36

What is indicated with low sagittal ratio?

Back 36

Perform myelogram to identify sites of cord compression and classify as static or dynamic

Front 37

What is indicated with moderate sagittal ratio?

Back 37

Perform myelogram to confirm or exclude CSM as a differential

Front 38

What is indicated with high sagittal ratio?

Back 38

No CSM

Front 39

What factors are important for surgical success with cervical cord compression?

Back 39

# of sites of compression, static or dynamic compression, severity of clinical signs, duration of clinical signs, temperament, age, and use of horse

Front 40

Approaches to ventral interbody fusion:

Back 40

kerf cut cylinder, LCP

Front 41

Complications of ventral interbody fusion:

Back 41

seroma, infection, fractures of the adjacent vertebral body, ventral migration of implant, laryngeal hemiplegia, horner's syndrome, if fixed with LCP screws can migrate if there is a gap between plate and bone at fixation

Front 42

Post-op care for ventral interbody fusion:

Back 42

45 days stall rest, 45 days hand walking, reradiograph at 60 days, turn out for at least 6 months or until clinical signs resolve

Front 43

How long can complete interbody fusion take?

Back 43

Up to a year

Front 44

When do clinical signs resolve after ventral interbody fusion?

Back 44

Can take up to a year

Front 45

Types of nerve injury:

Back 45

type 1 (neuropraxia) is compression of myelin sheath or alteration in cell membrane function; type 2 (axonotmesis) is disruption of the axon and myelin sheath; type 3 (neurotnesis) is disruption of axon, myelin sheath, endoneurium; type 4 is disruption of axon, myelin sheath, endoneurium, perineurium; type 5 is disruption of axon, myelin sheath, endoneurium, perineurium, epineurium

Front 46

characteristics of CSM

Back 46

flare of the caudal epiphysis of the vertebral body, abnormal ossification of the articular processes, subluxation between adjacent vertebrae, extension of the dorsal laminae, OA of articular processes

Front 47

ways to define myelographic spinal cord compression:

Back 47

50% or greater decrease in sagittal diameter of dorsal and ventral contrast columns or 20% reduction in dural diameter at C6-C7

Front 48

Back 48