Spine: C Flashcards
What is the rate of tandem myelopathy/stenosis
20% lumbar pathology w/ cervical myelopathy
What are parameters for congenital cervical stenosis
What equation can be used
<10mm space available for the cord
Avg normal 17
Torg = B/A = <0.8 = stenosis
3 ways an acute cervical disc presents
Central cord
Acute myelopathy
Cervical radiculopathy
What are the 3 RA C spine manifestations
Basilar invagination = migration of the dens into the foramen magnum
C1-2 instability 2/2 pannus destroys the TAL
Subaxial instability (“stair step” deformity)
Why do patients have balance issues with cervical myelopathy
Posterior cord compression / posterior elements
Lose proprioception
Shuffle / stumble bc dont know where your feet are in space
What is Lhermitte sign
Flex neck causes electric shock
Myelopathy
What is Wartenburgs sign
Slightly greater abduction of the fifth digit
Weakness adducting palmar interosseous muscle
Unopposed radial innervated extensor muscles (digiti minimi, digitorum communis)
Cervical myelopathy
What is the Japanese Ortho Association (JOA) classification
Score to determine if your cervical myelopathy will improve with surgery
<14 = likely to improve
Higher score = more functional
What is the determining factor to determine ant vs posterior for C spine surgery
KYPHOSIS
> 10deg, need some anterior procedure to restore lordosis
If more than 3 levels C spine involved, what surgery:
If >10deg kyphosis
If <10deg kyphosis or lordotic (normal)
Kyphotic - anterior AND posterior
Normal - posterior alone or ant/post
Why should you never choose an answer with cervical laminectomy alone? (aka without fusion)
Post laminectomy kyphosis
Instead choose laminoplasty or lami/fusion (what you think of with fishtail from the back)
Surgical approach for OPLL
Posterior
High rate dural tear from anterior
What is cervical laminoplasty
Make a cut in the lamina that use a plate to put back together but with a gap to preserve additional cord space
Motion preserving - facets left unfused
Expands the canal
Preserves the PLC, decreasing risk of kyphosis
When should you choose front/back C spine surgery
> 3 levels ACDF (pseudo rate)
1 corpectomy (higher rates of graft displacement)
Kyphosis correction (if large enough)
Pts with high risk pseudoarthrosis (smoker, prev pseudo, inflam arthropathy)
Ddx for cervical myelopathy
Stroke
Tumor
Vit B12 def
MS - vision changes, uniL motor/sens, get MR w/ contrast (demyelin lesions, periventricular plaques)
AML (Lou Gehrig) - will have atrophy, CSF sample for dx
When can you return a transient quadriplegia/cord concussion to play
Sx: neuropraxia that resolves in mins/hrs
Return to play with sx resolve and normal MRI
CANNOT return if MRI findings stenosis
What congenital cervical stenosis is a CI to return to play
Speak Tackler’s spine
Spine straightens with trauma
Treat basilar invagination (RA pts)
Occiput - C2 fusion
- No brain stem compression
- Occiput gives you a better level arm to lengthen with than C1
Anterior + posterior - if need brain stem decompression
What are the ADI thresholds for AA subluxation
ADI = posterior aspect of the anterior atlas ring and the anterior aspect of the odontoid process
> 3.5 between flex/ext XRs = instability
10mm = surgery indication
What are the PADI/SAC thresholds for AA subluxation
PADI/SAC = distance from posterior surface of dens to anterior surface of posterior arch of atlas
<14mm = surgery indication
Trt AA subluxation
C1/2 fusion
What is the collagen type for annulus fibrosis vs nucleus pulposus?
What is the disc blood supply?
AF = T1
NP = T2
BS = avascular, diffusion
What level do disc herniations affect in C spine
Nerve exits above the level
Really no traversing roots in C spine, so herniations always affect exiting root
Name the following dermatomes
C3
C6
C7
C8
C3 = occiput
C6 = thumb
C7 = middle finger
C8 = small finger
Name the motor group: C5 - T1
C5 = shoulder abduction (deltoid)
C6 = elbow flexion (BR) + wrist extension (ECRL)
C7 = elbow extension (triceps) + wrist flexion (FCR)
C8 = finger flexion/grip (FDS)
T1 = finger abduction (interossei)
What is the shoulder exam for patients with C spine radiculopathy
Improves with shoulder elevation / hand on head
What is considered instability on lateral flex/ex XRs
> 3mm shift or 11deg
Plate vs no plate for ACDF
Plate for multi level is standard bc of high subsidence rates
Indications / outcome for cervical disc replacement
Young, no arthritis, single level
Neck pain = relative CI
Think radiculopathy or acute myelopathy
Outcomes equiv to ACDF, possible decrease in adj seg dis
What are the soft tissue markers for the following levels: C2-6
C2 = angle mandible
C3 = hyoid
C4-5 = thyroid
C5-6 = cricoid
C6 = carotid tubercle
Innervation of
SCM
Strap muscles
SCM = CN 11 = accessory
Strap = ansa cervicalis
- Omohyoid
- Sternothyroid
- Sternohyoid
Contents of carotid sheath
Common carotid art
IJ
Vagus n
What is the location of screw fixation in the C spine
C1 = lateral mass
C2 = pedicle > translaminar > pars
C3-6 = lateral mass
C7 and below = pedicle
RF pseudarthrosis
Smoking
DM
Multi level surgery
Revision
Recurrent laryngeal nerve
- Which cranial nerve
- Cause
- Strategy for revisions
CN X = vagus
Traction injury
- Left around aortic arch
- Right around subclavian artery (superficial)
Revision - see ENT first, approach from the same side (aka don’t bag the other side nerve)
Cause/sx Hornerns syndrome
Over retraction of longus coli - sympathetic chain injury
Ptosis, miosis, anhidrosis
Hypoglossal nerve injury
- What nerve roots
- Sx
C2-3, C3-4
Tongue deviates to SAME SIDE as injury
Late presentation of esophageal injury
Mediastinitis - can be 50% mortality
Risk factors for adjacent segment disease cervical spine
Plate <5mm from the adjacent level (aka too close)
Smoking
F>M
What side is the artery of Adamkiewicz on? Spine levels
LEFT
T8-L1
How do you determine ASIA level
Most proximal level w/ bilateral motor >3/5 strength w/ sensory intact
How does neurogenic shock present
Low BP + HR
Bc of loss autonomic control aka sympathetic tone
What is the evidence of steroids with spinal cord injury?
Not indicated - no clear benefit, real risks
What is the operative timeline for incomplete vs complete spinal cord injury
Incomplete - surg <12hrs, goal to stabilize to save spinal function
Complete - surg <24hrs, goal to stabilize to facilitate rehab
Presentation for anterior cord syndrome
I.e. sp emergent aortic aneurysm repair
Anterior spinal artery injury
LE strength loss»_space; UE
Lose - motor, pain and temp
Keep - proprioception, vibration (dorsal column intact)
WORST PROGNOSIS
What spinal cord syndrome has the best outcome
Brown Sequard
Ipsilateral motor
CL pain and temp
Describe DISH spine
Nonmarginal syndesmophytes
Flowing candle wax XRs
Older pts
NO SI jt involvement
Associated with DM
Describe disc space DISH vs ank spond
DISH - disc space preserved
Ank spond - ossified
What is the HLA for DISH vs ank spond
DISH - HLA B8
Ank spond - HLA B27
Describe ank spond spine
Marginal syndesmophytes
Bamboo spine, squared vertebral bodies
YOUNGER pts
Bilateral SI joint involvement
When do you decompress a spinal epidural abscess
Weakness / deficits
What is the C2 watershed area
Apex of dens - internal carotid
Base dens - vertebral art
Treat the types of dens fractures
T1 - apex, nonop
T2 - waist, highest rate non union
<50
- Nonop = halo
- Op = displaced w/ non union risk factors
> 50
- Non op - orthosis (NEVER halo)
- Unlikely to be operative candidate
T3 - body, non op
What restriction is placed on people with os odontoideum
CI contact sports
What are RF for type 2 odontoid nonunion
Older (>50)
>6mm displaced **greatest RF
>10deg post angulation
Comminution
Delayed treatment
DM
What are the operative techniques for type 2 odontoid frx
C1-2 screw
- C2 pedicle > translaminar > pars
Wire w/ C1-2 transarticular screw
- If aberrant vert art = ABSOLUTE NO
Anterior screw
- Perpendicular frx
- Intact TAL
- No barrel chest
How do you determine if a C1 fracture is operative
Sum of lateral mass displacement on open mouth >8.1mm = TAL injury = unstable
Trt with occ-C2 fusion
Trt cervical facet dislocation
Alert/NV intact = CR -> MRI -> OR
AMS/deficits = MR -> OR
What is the difference in operative strategy for cervical facet dislocation that can be reduced vs not
ACDF alone if reducible / unilateral
Consider front back if not reducible
What other injuries are associated with cervical facet dislocation
Occipitocervical dissociation
Transverse foramen fracture
Basilar skull fracture
What are two subaxial C spine injuries that have anterior bone flecks? How treat differently?
Extension tear drop / avulsion = mild ext injury
- Orthosis
Flexion teardrop = ant frag stays with ALL, posterior frag retropulses into the canal
- Ant vs ant/post fixation
Treat a floating lateral mass
Lamina and pedicle
2 level fusion
- Post if need reduction
- Anterior if already reduced
What fractures are good for halo
Upper cervical - controls flex/ex and rotation
NOT good for subaxial spine
- Poor control of lateral bend
- Bell ringer phenomenon = increased subaxial motion with a halo on
Absolute CI for halo
Cranial frx
Infx
Soft tissue injury preventing pin placement
<2yo
pins and # inch-pounds for halo pins
Kids vs adults
Adults: 4 pins, 8 inch-lbs
Kids: 8 - 4
What is safe pin placement for adults halo
Ant pin:
- lateral side of orbit
- 1cm above supra-orbital ride
- Nerves at risk = supraorbital and supratrochlear
Post pin
- 180 deg from ant
BOTH below the equator
Nerve palsy seen for halos
Abducens (CN 6) = one eye drifts centrally
What do SSEPs measure?
Pro/con
What are the alert levels?
Somatosensory evoked potentials
SENSORY = dorsal column
Transcranial leads read somatosensory cortex response
Con: slower to respond to injury
Pro: less influenced by anesthetics
Alert level:
- Drop 50% amplitude
- Increase 10% latency
What do MEPs monitor?
Con
Alert level
Motor evoked potentials
MOTOR
Transcranial stim motor cortex - measure the muscle contraction
Detect anterior cord injury (ischemia)
Con: can be unreliable depending on anesthesia
Alert
- >75% decrease in amplitude (sustained)
