Intervertebral Disc Disease

Question 1

does concussion or compression cause more spinal cord damage?

Answer 1

concussion

Question 2

what type of injury does disc protrusion cause?

Answer 2

compressive spinal cord injury

Question 3

what is compressive extrusion like?

Answer 3

disruption of dorsal annulus
penetration of dorsal ligament
compression
fast, progressive

Question 4

where can disc material be in concussive extrusion?

Answer 4

can penetrate dura: subdural, intramedullary

Question 5

when is early decompression beneficial?

Answer 5

ischemic spinal cord lesions

Question 6

which discs are more common in small dogs with intervertebral disc disease in the neck?

Answer 6

C2/3
C3/4
C4/5

Question 7

what happens in hydrated nucleus pulposus extrusion?

Answer 7

primary rupture of annulus fibrosus
extrusion of liquid and gelatinous nucleus pulposus
peracute onset

Question 8

what happens in disk-associated excessive extradural hemorrhage?

Answer 8

fragmented disc herniation combined with excessive and dispersed bleeding

Question 9

does extrusion or spinal cord compression produce more spinal cord trauma?

Answer 9

extrusion

Question 10

what is penetrated by the nucleus pulposus with high velocity in intradural intervertebral disc extrusion?

Answer 10

dura mater

Question 11

what clinical signs are related to outcome?

Answer 11

speed of onset
presence or absence of pain perception

Question 12

what percentage of dogs that are non-ambulatory and have pain perception will completely recover after surgery?

Answer 12

about 90%

Question 13

what is the cause of myelomalacia?

Answer 13

severe spinal cord trauma

Question 14

what patients with disc herniation can you use medical management for?

Answer 14

pain only
minimal proprioceptive deficits
minimal paraparesis

Question 15

what are the advantages of a hemilaminectomy?

Answer 15

large window
good visualization of disc extrusion
in lumbar area careful approach to important nerve roots

Question 16

what are the advantages of a pediculectomy?

Answer 16

small window
better vertebral stability because dorsal articulation not removed
less risk of laminectomy scar

Question 17

what is non-chondrodystrophic disc degeneration like?

Answer 17

degenerative
fibroid metamorphosis
onset in middle aged to older
affects single disc space

Question 18

what is chondrodystrophic disc degeneration like?

Answer 18

inherited, multifocal
chondroid metamorphosis, calcification
onset at young age
affects all intervertebral discs

Question 19

what are the types of disc herniation?

Answer 19

protrusion: hansen II
extrusion: hansen I, compressive or concussive

Question 20

what is disc protrusion like?

Answer 20

annular weakness or partial disruption
dorsal ligament intact
more non-chondrodystrophic
compressive injury
chronic

Question 21

what is compressive extrusion like?

Answer 21

disruption of dorsal annulus
penetration of dorsal ligament
more chondrodystrophic
compression
acute
major amount of disc under or around displaced spinal cord

Question 22

is compressive extrusion or disc protrusion more in chondrodystrophic?

Answer 22

compressive extrusion

Question 23

what is concussive extrusion like?

Answer 23

high velocity
peracute rupture of annulus fibrosus
damage to venous plexus
may penetrate dura- subdural, intramedullary disc material
concussion with some compression

Question 24

does early or late decompression make a difference if there is no pain perception?

Answer 24

no
yes if ischemic lesions- still have pain

Question 25

are any medications proven to minimize the effects of the secondary cascade in acute spinal cord injury?

Answer 25

no: only surgical decompression or vertebral stabilization
possibilities are out there

Question 26

which discs are affected more in large dogs with IVDD in the neck?

Answer 26

C4/5
C5/6
C6/7
C7/T1

Question 27

which discs are affected more in the thoracolumbar region with IVDD in all dogs (no small/large difference in thoracolumbar)?

Answer 27

T11/12
T12/13
T13/L1
L1/2
L2/3

Question 28

what can be seen on an MRI with compressive extrusion?

Answer 28

extrusion of degenerative nucleus pulposus, secondary rupture annulus fibrosus
fragments nucleus pulposus dispersed
some focal blood

Question 29

what happens in acute non-compressive nucleus pulposus extrusion?

Answer 29

suspected primary rupture of annulus fibrosus
high velocity extrusion of shower of small pieces of nucleus pulposus

Question 30

what is intradural intervertebral disk extrusion like?

Answer 30

suspected primary rupture annulus fibrosus
extrusion of small amount nucleus pulposus with high velocity
penetration of dura mater
nucleus pulposus subdural or intramedullary

Question 31

what is myelomalacia?

Answer 31

progressive ascending or descending spinal cord necrosis

Question 32

what are the clinical signs of myelomalacia?

Answer 32

no pain perception
loss spinal reflexes caudal to lesion
ascending panniculus reflex
dog painful or restless
respiratory difficulty
sudden death

Question 33

what are the indications for surgery for disc herniation?

Answer 33

recurrent, severe pain
moderate to severe ambulatory paraparesis-tetraparesis or ataxia
non-ambulatory function
paraplegia with no pain perception, tetraplegia with respiratory compromise

Question 34

what are the surgical options for disc herniation?

Answer 34

hemilaminectomy
dorsal laminectomy
ventral slot- neck
pediculolectomy

Question 35

what are the advantages of a ventral slot?

Answer 35

limited muscular dissection
fast procedure
shorter recovery time, shorter in hospital
less painful post surgery

Question 36

what is the width of a ventral slot?

Answer 36

33% of vertebral diameter
limitation

Question 37

what is a pediculectomy indicated for?

Answer 37

ventral and ventro-lateral disk extrusions only
technically more difficult

Question 38

is IVDD more common in the cervical spine or thoracolumbar spine?

Answer 38

thoracolumbar

Question 39

how common is myelomalacia?

Answer 39

10-17% of absent pain perception dogs