Intervertebral Disc Disease Flashcards
does concussion or compression cause more spinal cord damage?
concussion
what type of injury does disc protrusion cause?
compressive spinal cord injury
what is compressive extrusion like?
disruption of dorsal annulus
penetration of dorsal ligament
compression
fast, progressive
where can disc material be in concussive extrusion?
can penetrate dura: subdural, intramedullary
when is early decompression beneficial?
ischemic spinal cord lesions
which discs are more common in small dogs with intervertebral disc disease in the neck?
C2/3
C3/4
C4/5
what happens in hydrated nucleus pulposus extrusion?
primary rupture of annulus fibrosus
extrusion of liquid and gelatinous nucleus pulposus
peracute onset
what happens in disk-associated excessive extradural hemorrhage?
fragmented disc herniation combined with excessive and dispersed bleeding
does extrusion or spinal cord compression produce more spinal cord trauma?
extrusion
what is penetrated by the nucleus pulposus with high velocity in intradural intervertebral disc extrusion?
dura mater
what clinical signs are related to outcome?
speed of onset
presence or absence of pain perception
what percentage of dogs that are non-ambulatory and have pain perception will completely recover after surgery?
about 90%
what is the cause of myelomalacia?
severe spinal cord trauma
what patients with disc herniation can you use medical management for?
pain only
minimal proprioceptive deficits
minimal paraparesis
what are the advantages of a hemilaminectomy?
large window
good visualization of disc extrusion
in lumbar area careful approach to important nerve roots
what are the advantages of a pediculectomy?
small window
better vertebral stability because dorsal articulation not removed
less risk of laminectomy scar
what is non-chondrodystrophic disc degeneration like?
degenerative
fibroid metamorphosis
onset in middle aged to older
affects single disc space
what is chondrodystrophic disc degeneration like?
inherited, multifocal
chondroid metamorphosis, calcification
onset at young age
affects all intervertebral discs
what are the types of disc herniation?
protrusion: hansen II
extrusion: hansen I, compressive or concussive
what is disc protrusion like?
annular weakness or partial disruption
dorsal ligament intact
more non-chondrodystrophic
compressive injury
chronic
what is compressive extrusion like?
disruption of dorsal annulus
penetration of dorsal ligament
more chondrodystrophic
compression
acute
major amount of disc under or around displaced spinal cord
is compressive extrusion or disc protrusion more in chondrodystrophic?
compressive extrusion
what is concussive extrusion like?
high velocity
peracute rupture of annulus fibrosus
damage to venous plexus
may penetrate dura- subdural, intramedullary disc material
concussion with some compression
does early or late decompression make a difference if there is no pain perception?
no
yes if ischemic lesions- still have pain
are any medications proven to minimize the effects of the secondary cascade in acute spinal cord injury?
no: only surgical decompression or vertebral stabilization
possibilities are out there
which discs are affected more in large dogs with IVDD in the neck?
C4/5
C5/6
C6/7
C7/T1
which discs are affected more in the thoracolumbar region with IVDD in all dogs (no small/large difference in thoracolumbar)?
T11/12
T12/13
T13/L1
L1/2
L2/3
what can be seen on an MRI with compressive extrusion?
extrusion of degenerative nucleus pulposus, secondary rupture annulus fibrosus
fragments nucleus pulposus dispersed
some focal blood
what happens in acute non-compressive nucleus pulposus extrusion?
suspected primary rupture of annulus fibrosus
high velocity extrusion of shower of small pieces of nucleus pulposus
what is intradural intervertebral disk extrusion like?
suspected primary rupture annulus fibrosus
extrusion of small amount nucleus pulposus with high velocity
penetration of dura mater
nucleus pulposus subdural or intramedullary
what is myelomalacia?
progressive ascending or descending spinal cord necrosis
what are the clinical signs of myelomalacia?
no pain perception
loss spinal reflexes caudal to lesion
ascending panniculus reflex
dog painful or restless
respiratory difficulty
sudden death
what are the indications for surgery for disc herniation?
recurrent, severe pain
moderate to severe ambulatory paraparesis-tetraparesis or ataxia
non-ambulatory function
paraplegia with no pain perception, tetraplegia with respiratory compromise
what are the surgical options for disc herniation?
hemilaminectomy
dorsal laminectomy
ventral slot- neck
pediculolectomy
what are the advantages of a ventral slot?
limited muscular dissection
fast procedure
shorter recovery time, shorter in hospital
less painful post surgery
what is the width of a ventral slot?
33% of vertebral diameter
limitation
what is a pediculectomy indicated for?
ventral and ventro-lateral disk extrusions only
technically more difficult
is IVDD more common in the cervical spine or thoracolumbar spine?
thoracolumbar
how common is myelomalacia?
10-17% of absent pain perception dogs
