Spinal cord disorders

Question 1

Complete cord injury pathology

Answer 1

traumatic SCI most common cause
True transection is rare
Hemorrhage into grey matter with disruption of axons in white matter
Other causes: cord compression by tumor or abscess

Spinal shock:
hypotonia and loss of all reflexes below lesiona fter acute spinal cord injury
days to weeks
Functional disruption of segmental spinal reflexes due to loss of supraspinal descending input

Poor prognosis unless some recovery seen within 24 hours

Question 2

Brown sequard syndrome

Answer 2

L>R
spinal cord hemisection
Ipsilateral loss of tactile sensation and proprioception
Contralateral loss of PT sensation

Question 3

Central cord syndrome

Answer 3

commonest in cervical spine in the elderly
LMN weakness at lesion level
variable UMN features below level of lesion (CST)
arm weakness > leg
DTR: decreased at injury level, N or increased above level (if CST involved)
Sensory: suspended - crossing PT fibers in central grey affected by central lesion
Dissociated: decreased PT with sparing of vibrations, position sense and light touch

Question 4

Central cord syndrome causes

Answer 4

trauma, especially with underlying narrow spinal canal
Intramedullary tumour/syringomyelina

usually an incomplete injury with some partial recovery

Question 5

Anterior spinal artery infarct

Answer 5

anterior 2/3 cord infarction
Only a few (4-7) anterior raduclar arteries along the length of the spinal cord contributes to ASA

Paralysis and loss of PT
normal light touch, vibration and position sense

Question 6

Ant spinal arter territories

Answer 6

cervical and upper thoracic: often >3 radiculars: protected
Mid-thoracic (T4-8): often only small single radicular vessel
Below T8: large single Artery of Adamkieqicz arising on left between T9-L2: supplies lumbar enlargement

Question 7

ASA infarct causes

Answer 7

thrombosis
embolism
surgery on descending aorta (e.g. aneurysms)

Question 8

Subacute combined degeneration/B12 deficiency

Answer 8

gradual onset weakness (legs> arms) and gait imbalance
UMN weakness (DTR may be decreased with polyneuropathy)
absent vibration and position sense
light touch, PT less affected or later
Gait ataxia and + Romberg (PCML and spinocerebellar)
Anemia and/or polyneuropathy frequently associated
Demyelination of posterior and lateral columns (esp CST and spinocerebellar) - starts in thoracic cord
Axon loss uncommon, grey matter spared
Deficiency causes decreased coenzyme NB for maintenace of myelin basic protein and rapid cell replication

Question 9

Acute cauda equina compression

Answer 9

herniated L4/5 disc
Rapid progressi nfo leg weakness, numbness and sphincter disturbance
LMN features, reduced all sensory modalities, reduced rectal tone
Large central disc herniation on CT or MRI
Other causes: L-spine fracture/subluxation, epidural metastatic tumour, hematoma, abscess
Urgent decompression needed - poor recovery if complete loss of function or >48 h of sphincter loss

Question 10

X-ray advantages

Answer 10

best tool of looking at alignment (scoliosis, kyphosis)

Question 11

CT advantages

Answer 11

best for:
- assessing cortical bone
- assessment of hardware position after fixation surgery
- detection o foraminal/spinal stenosis, esp in lumbar spine
- detection of calcium/bone
primary modality for trauma

Question 12

MRI advantages

Answer 12

best for:

• marrow - myeloproliferative disorders, metastases, recent fractures
• soft tissue: disc herniations, ligamentous injuries, post-disectomy
• spinal cord: MS, tumours, myelopathy, syringomyelia, cord compression
• infections: discitis/osteomyelitis, epidural abscess

Question 13

Nerve root

Answer 13

diagnostic to confirm which root is the site of pathology
relieves radiculopathy from weeks-months as a temporizing measure
can be technically challenging, especially at cervical levels with small risk of stroke, dissection

Question 14

Facet block/rhizotomy

Answer 14

diagnostic and therapeutic steroid injection

Rhizotomy destroys the nerve that innervates the facet with radio-frequency ablation

Question 15

Vertebroplasty

Answer 15

acute osteoporotic compression fractures not responsive to conservative management
also as treatment of vertebral hemangiomas, palliation of metastases
Risk of extravasation of the cement into the canal, pulmonary cement emboli
Risk of delayed adjacent vertebral body compression fractures

Question 16

Spinal angiogram

Answer 16

For suspected vascular abnormality - AV fistula/malformation
Embolise a known vascular abnormality/tumour: renal cell metastasis to bone prior to resection/stabilization surgery
technically challenging - segmental arteries from clivus to pelvis
Takes 2-6 hours; significant radiation dose, generally performed under GA

Question 17

Anterior longitudinal ligament

Answer 17

anterior to vertebral body and attaches via Sharpey’s fibers to periosteum of vertebral body along with outer part of disc (annulus fibrosis)

Question 18

Intraspinal contents (external to internal)

Answer 18

vertebra
epidural space
Dura mater
Subdural space
Arachnoid mater
Subarachnoid space
Pia mater
Spinal cord - white matter, grey matter, central canal

Question 19

Foraminal herniation at L4-5

Answer 19

involves exiting L4 nerve root as it enters foramen, just under pedicle

Question 20

Paracentral/subarticular herniation at L4-5

Answer 20

will involve traversing L5 root