Lumbosacral Disease Flashcards
cauda equina
bundle of nerve roots caudal to the conus medullaris
peripheral nerves NOT spinal cord
conus medullaris
end of the spinal cord
do all spinal segments line up with the vertebral bodies
NO - spinal cord is shorter than the vertebral column
lines up from T1 to L2
in dogs - what vertebrae does the sacral cord begin at
sacral cord begins at L5
where do majority of nerve roots exit from the vertebrae to become spinal nerve
exit out of the foramen CAUDAL to the corresponding vertebrae
(ex. spinal nerve L2 exits out of the foramen between L2 and L3)
what are the short spinal nerves
- cervical
- thoracolumbar
just need to travel straight across because T1 to L2 lines up with corresponding vertebrae
what are the long spinal nerves
- caudal lumbar
- sacral
- caudal
have to travel caudally before they can exit
(ex. spinal nerve L7 originates at L4-5 and must travel down to L7-S1 to exit)
where do nerve roots C1-7 exit from the vertebrae to become spinal nerves
exit out of the foramen CRANIAL to the corresponding vertebrae
(ex. spinal nerve C2 exits between C1 and C2)
is there a C8 spinal nerve and vertebrae
there is a C8 spinal nerve but NO C8 vertebrae
C8 spinal nerve exits between C7 and T1
what structure do all sacral and caudal nerve roots pass over before exiting out of the vertebral foramen
L7 to S1 disc space
what are the differences between the cauda equina and spinal cord
cauda equina is made of peripheral nerves NOT spinal cord
- more robust/hardy; can be manipulated during surgery if needed
where does the spinal cord end/cauda equina begin in dogs and cats
L7 to caudal nerve roots
dogs: L6-7
cats: L7-S1
what are the most important peripheral nerves that arise from the cauda equina
- sciatic nerve (L6 to S2)
- pudendal nerve (S1 to S3)
- pelvic nerve (S1 to S2)
cauda equina syndrome (CES)
group of neurologic signs caused by a lesion affecting the cauda equina
can NOT differentiate from a L7-caudal myelopathy (normal thoracic limbs, LMN signs in pelvic limbs)
- must rule out L7-Cd myelopathy
general clinical signs of CES and L7-Cd myelopathy
- motor
- bladder
- sensory
- patellar reflex
- apparent pain
motor signs CES/L7-Cd
LMN signs in PLs, tail, and anus
- tail: reduced carriage, wag, flaccidity
- anus: reduced/absent perineal reflex, fecal incontinence
- PLs: reduced withdrawal and gastrocnemius reflexes, plantigrade stance, reduced flexion of hock and stifle, neurogenic muscle atrophy, difficulty rising/jumping, scuffing, paraparesis
note: NOT paraplegic - hip flexors are still functional
bladder signs CES/L7-Cd
unable to urinate or completely empty bladder
loss of bladder tone on palpation
dribbling urine (history of UTI)
sensory signs CES/L7-Cd
- CP deficits
- abnormal sensation (paresthesia, hyperesthesia, hypesthesia, anesthesia of PLs and tail)
patellar reflex signs CES/L7-Cd
“pseudo-hyperexaggeration”
- appears like UMN signs but is not
- actually caused by a prolonged extension phase of the reflex –> “lazy extension” (slow not exaggerated)
caused by loss of antagonism on the muscles innervated by the femoral nerve by muscles innervated by the sciatic nerve
apparent pain of CES/L7-Cd
- reluctance to jump/rise
- pain on tail extension
- pain on spine palpation
- hunched/crouched position
- pain on LS joint palpation
- lameness
compensation for PL lameness by putting weight on TLC
CES diagnosis
rule out myelopathies using:
- history, PE, NE, minimum database, CSF analysis
- dynamic rads of entire vertebral column
- CT, MRI
- electrophysiology (NM disease)
- aspirates - cytology or culture
- surgical exploration
what are differentials for CES
- degenerative (IVDD)
- anomalous
- infectious
- trauma
lumbrosacral stenosis
degenerative condition that occurs secondary to IVDD type II, hypertrophy/hyperplasia of ligaments, thickening of vertebral arch/facets +/- instability
lumbosacral stenosis signalment
breeds: large breed (GSDs)
age: middle to older
lumbosacral stenosis clinical signs
slowly progressive trouble rising
ranges from no deficits +/- pain to LMN signs with urinary and fecal incontinence
can be asymmetrical lameness
LSS diagnostics
- ortho exam
- spinal rads
LSS treatment and prognosis
tx: conservative vs surgical (dorsal laminectomy + stabilization)
prognosis: good if mild signs, poor if incontinent
congenital malformations causing CES
spina bifida
myelomeningocele
sacrocaudal dysgenesis
causes compression/disease of the cauda equina
discospondylitis
infection of the disc and adjacent vertebral bodies
common at lumbosacral junction
often affects multiple endplates
causes of discospondylitis
- direct (bite wound, migrating grass awn)
- hematogenous (dental disease, endocarditis)
discospondylitis signalment
breed: large
age: young but can be any
discospondylitis clinical signs
- fever
- marked spinal hyperesthesia
- NO neurologic deficits
discospondylitis diagnosis
- radiographs - end plate destruction, aggressive bone lesion, +/- pathologic fractures
- blood and urine cultures
- disc space aspirates
discospondylitis treatment and prognosis
tx: long term antibiotics (4-6 months) + rest
prognosis: good for bacterial, poor for fungal
trauma to cauda equina
very common - CE is able to tolerate more instability and displacement than the spinal cord
treatment is surgical
