Spine Flashcards
Vertebral compression fx palm fxn
Each decreases ~10%, increased risk of mortality from pulm dysfxn
Vert compression fx 1 and 2 year mortality
1 year 15% (less than hip fx)
2 year 20% (same as hip fx)
Kyphoplasty indications and technique
Pain >6 wks with vert compression fx
AAOS recommended use, though limited
Transpedicular approach for canal –> Cavity created w/ ballon and injected w/ cement
Osteoporotic VCF imaging vs malignant VCF
osteoporotic VCF - low T1, high T2 and STIR
Malignant VDF - complete replacement of normal marrow, convex posterior cerebral border, pedicle involvement, mass
Only Tx with moderate evidence for osteoporotic VCF by AAOS?
Calcitonin for 4 weeks for acute injury (directly inhibits osteoclast activity by binding to surface cell-surface receptors)
Mortality risk order: DRF, VCF, hip fx?
Hip fx > VCF > DRF
Injury ass’d with chance fx?
Concomitant bowel injury (colonic rupture)
Predictors of medical tx failure for epidural abscess?
Neuro deficits (strongest) DM CRP >115 WBC >12 age >65 MRSA
Pott’s dz/TB of spine XR/imaging
Predilection for anterior vertebral body, spares disk space until late, significant kyphosis/gibbus deformity
Pavlov ratio - definition and when causes issue in cervical spine?
Width of spinal canal divided by width of vertebral body
<0.8 = congenitally narrow canal
Cervical compression ratio definition and when issue in cervical spine?
CR = smallest AP diameter of cord/ largest transverse diameter
CR <0.4 has poor prognosis
Size of cord/dimension amendable to nonop tx in cervical myelopathy?
Larger transverse area of spinal cord (>70 mm2)
C5 palsy rates after ACDF and timeline to resolve?
3-12%
Resolve at 4-6 months
Contraindication for anterior only cervical operation (angle)?
Kyphosis >13 degrees
Risk factors for airway complications after ACDF?
Exposing >3 vertebral bodies
Blood loss >300 mL
Exposure upper cervical (C2-C4)
Operative time >5 hours
Smoking is NOT a risk factor
UMN Sx?
LMN Sx?
Exaggerated reflexes
Clonus
Spasticity
Weakness
Fasciculations
Flaccid paralysis
How often do cervical selective nerve root injxns provide long term relief?
40-70%
Time preop and postop for smoking cessation to decrease chance of pseudoarthrosis in cervical surgery?
4 weeks preop
6 months postop
ADI defining instability in RA? Indication for surgery?
Instability: >3.5 mm of motion on flex/ext
Surgery: >10 mm motion
PADI/SAC indication for surgery in RA? What rads finding predicts recovery after decompression?
surgery: <14 mm
>13 mm is MOST important rads finding to predict complete neural recovery after surgery
Indications for C1-2 fusion in RA vs O-C2?
C1-2: ADI >10 mm, PADI/SAC <14 mm
O-C2: same as above WITH basilar invagination
Basilar invagination definition? How to measure? MRI?
Def: superior migration of odontoid –> tip of odontoid above foramen magnum
Measure on XR with Runaway C1-C2 index: center of C2 pedicle to a line connecting the anterior and posterior arches of C1 (Nl 15-17 mm), distance <13 mm = impaction
MRI: Cervicomedullary angle <135 deg indication for surgery
Most common site for spine synovial cyst?
L4-5 (60-90%), most mobile segment
Pathology of synovial cyst?
Synovial cells covering a stroma with vascular granulation tissue
Most common level for lumbar disk herniation? What %improve with nonop?
L5/S1, 3:1 M:F ratio, only 5% symptomatic
90% improve in 3 months w/ nonop
Sequestered disc herniations (free fragment) greatest spontaneous resorption (macrophage phagocytosis)
MRI w/ contrast post op fibrosis vs recurrent herniated disc?
Postop fibrosus - enhances w/ gad
Recurrent herniated disc - does NOT enhance
Indications for microdiscectomy?
- Pain >6 weeks failed nonop
- Progressive weakness
- Cauda equina
Size definition of central lumbar stenosis?
<100 mm^2 or <10 mm A/P on axial CT
Strongest predator of clinical outcome after lumbar spine decompression?
Comorbid conditions
Characteristics ass’d w/ good outcome with lumbar disc herniation surgery?
Age>41 years
Absence of joint problems
Married
Most common site of Adult isthmic spondylolisthesis?
82% at L5/S1
11% at L4/5
-Facets more coronal at these levels, forces greatest in lumbar spine at these levels
Which level will isthmic spondy at L5/S1 affect?
L5 - foraminal stenosis causing compression of exiting nerve root (L5)
Types of spondylolisthesis (I through V)
Type I: Dysplastic (congenital defect in pars)
Type II: Isthmic (pars fatigue fx, healed stress fx, acute fx)
Type III: Degen - facet instability w/o pars fx
Type IV: Traumatic -acute posterior arch fx other than pars (ex: pedicle fx)
Type V: Pathologic destruction of pars
Definition of instability on flex/ext films/lumbar spine?
4 mm translation
10 degrees angulation of motion compared to adjacent motion segment
Levels to fuse for low grade and high grade spondylolisthesis (adult) at L5/S1?
Failed nonop for 6 months
- Low grade: L5-S1 decompression/fusion
- High grade: L4-S1 decompression/fusion
Annulus fibrosus composition? collagen:proteoglycan ratio?
vs nucleus pulposus?
Annulus fibrosus
Type I collagen, oblique oriented fibers
high collagen/low proteoglycan
Nucleus pulposus
Type II collagen, 88% water
Proteoglycans interact w/ water and resist compression
Aggrecan responsible for maintain water content of disk**
Low collagen/high PG **
Herniated disk ass’d with increased production of what factors?
Disc aging causes what changes?
OPG
IL-1 beta
RANKL/ NF kappa B
PTH
Disc aging:
loss of H20 and conversion to fibrocartilage***
Decrease in: Nutritional transport H20***, # viable cells Proteoglycans*** pH
Increase in:
Keratin sulfate to chondroitin sulfate ratio*
lactate, degradative enzyme activity
Density of fibroblast like cells** (these reside in annulus only ***)
NO CHANGE in quantity of collagen***
What is annulus fibrosus derived from? Nucleus polposus?
Annulus: sclerotome***
Nucleus: Notochord***
Which molecule increases intervertebral discs production of MMPs, NO, IL-6 and PGE2?
Interleukin-1 beta***
Where does neovascularization of the intervertebral disc originate with aging?
From the outer annulus fibrosus***
Embryology of spinal cord
Neural tube becomes? If doesn’t close cranially? Caudally?
Neural crest becomes?
Notocord?
Neural tube comes spinal cord***
Formed from primitive streak –> primitive/midsagittal groove –> Neural tube
Failure to close cranially = anencephaly
Failure to close caudally - spina bifida occult, meningocele, myelomenigocele
Neural crest
Dorsal to neural tube***
becomes: peripheral nervous system, pia mater, spinal ganglia, sympathetic trunk
Notocord
Forms ventral to neural tube***
Becomes: vertebral bodies, discs
Which direction do ankylosing spondylitis THAs risk dislocation?
Anterior***
Acetabulum is more vertical and anteverted
Which chromosome for AS/HLA B27?
Which HLA for DISH in patients with DM?
Major locus in MHC on chromosome 6
HLA-B8 ass’d w/ DISH in patients with diabetes
Eponym for DISH?
Forestier disease
Diagnostic criteria for DISH?
Flowing ossification along anterolateral aspect of at least 4 continuous vertebrae*
Preservation of disk height*
Absence of facet-joint ankylosis/SI erosion
Throacic spine often involved in isolation
usually T7-T11 on RIGHT side
DISH vs AS mortality after cervical spine trauma? Overall mortality?
DISH has higher mortality after cervical spine trauma than AS***
DISH and AS have similar overall mortality***
Pediatric spondylolisthesis: what % with pars lesion progress to slip?
What level most common?
Risk of progression?
15% w/ pars lesion progress to spondy***
Most common level = L5-S1***
Risk for progression: larger slips, dysplastic slips
PE of peds spondy?
Flattened lumbar lordosis
Palpable step off of SP’s
Limited flex/Exxt
Pain w/ single limb standing lumbar extension **
Measure popliteal angle to eval for hamstring tightness
How to measure slip angle?
Slip angle vs PI relations to spondy?
1: draw line on posterior aspect of sacrum
2: Mark cephalic point on S1
3: draw line through cepahlad point that is 90 deg to first line over post sacrum
4: Draw line on inferior endplate of L5
5: measure angle between line drawn in step 3 and 4
Slip angle vs PI
Slip angle correlates with PROGRESSION*
PI correlates with SEVERITY OF DISEASE*
Operative tx of spondylolysis?
Pars repair for L1 to L4 isthmus defect that failed nonop
L5-S1 in situ fusion:
L5 spondylolysis that fails nonop***
Grade I or II spondy
L4-S1 fusion +/- reduction, +/- ALIF
High grade spondy
Common gait with peds spondy?
Shortened stride length with flexion at hips and knees***
Tx of + imaging for spondylolysis in peds with pain?
TLSO bracing
NOT PT***, avoid strenuous activities to prevent formation pars defect completing
Tx of atlantoaxial rotary displacement: <1 week >1 week >1 month >3 months
<1 week - soft collar, NSAIDs
> 1 week: halter traction, NSAIDs, Benzos, then hard collar for 3 months
tx w/ 5 lbs at home or hospital
> 1 month: halo traction, then halo vest for 3 months
Also for failed halter traction x2 weeks
> 3 months: Posterior C1/C2 fusion
Also if there is a Neuro deficit or recurrent subluxation
What is Grisel syndrome?
Spontaneous atlantoaxial rotary sublimation that occurs after an acute URI
Tx with soft collar for one week
If no improvement, then transition to halter traction + muscle relaxants for 3 weeks
if no improvement then halo traction
If no improvement, then C1-C2 fusion
What conditions ass’d with congenital torticollis?
PE of congenital torticollis?
Other packaging disorders:
DDH
Metatarsus adductus
PE: head tilt TOWARD affected side and chin AWAY from affected side
AIS age definition?
Most common curve?
When to get an MRI?
Age: 10-18 y/o
Most common: right thoracic curve***
MRI: Left thoracic curve, short angular curve, apical kyphosis, rapid progression, neuro sx, foot deformities, abnormal abdominal reflexes***
natural hx of AIS if not treated?
Increased incidence of acute and chronic pain in adults if left untreated
Curves >90 deg ass’d w/ cardiopulmonary dysfunction, early death, pain, decreased self image
Risk factors for curve progression in AIS?
Curve magnitude***
Before skeletal maturity: >25 will continue to progress
After maturity: >50 thoracic will progress 1-2 deg/yr
>40 deg lumbar will progress 1-2 deg/year
Remaining skeletal growth*
Younger age, <12 at presentation
Tanner <3 for females
Risser 0-1** (Risser 0 = first 2/3 of pubertal growth spurt)
Open irradiate cartilage **
‘Peak growth velocity* –> BEST predictor of curve progression
Peak velocity happens in females just before menarche and before Risser 1 –> correlates with Tanner-Whiehouse III RUS
Stable vertebrae?
Neutral vertebrae?
End vertebrae?
Apical vertebrae?
Stable: Most proximal vertebrae that is most closely bisected by central sacral line
Neutral: rotationally neutral SP on PA XR
End: Vertebra most tilted from horizontal apical vertebra (where measure from)
Apical: deviated farthest from center of vertebral column
Tx of AIS - when to observe, when to brace, OR?
Observation: <25 deg
Bracing: 25-45 deg
Must wear 13 hrs/day (50% reduction in need for surgery with compliant brace wear)**
OR: Cobb >45 deg
Bracing of AIS: who does worse?
What type of brace for above T7? Below T7?
What defines bracing success?
What defines skeletal maturity in AIS?
Bracing for 25-45 deg
Must use 13 hrs/day*** (Recommended 16-23 hrs/day)
13 hours give success 90-93% of time in lvl 1 studies**
Poor prognosis: Poor brace fit Hypokyphosis (relative contra) Male Obese Noncompliant
Above T7: Milwaukee (CTLSO)
Below T7: TLSO
Success: <5 deg curve progression
Skeletal maturity: Risser 4, <1 cm height change over 2 visits >6 mo apart, 2 years postmenarchal
Neurocentral synchondrosis (NCS) develops between which 2 spinal elements and closes in what order?
Centrum and posterior neural arches
Cervical (6 y/o), then lumbar (12 y/o), then thoracic (14-17 y/o)
NCS is growth plate implicated as potential cause of AIS
Patient has congenital scoliosis, what imaging tests to get?
MRI of entire spine
Renal u/s **
Echo **
Which side of the spinal curve does an osteoid osteoma occur?
What portion of the spine does osteoid osteoma occur on?
Side: concave portion of the curve
Portion: posterior elements usually, can be in the vertebral body
AS vs DISH
Which undergoes more OR?
Which has more neuro events due to vascular issue?
Higher mortality?
HLA B8?
AS undergoes more OR***
More vascular issues in AS due to EPIDURAL HEMATOMA due to tethering of epidural vessels***
Mortality equal overall for the two
HLA B8 = DISH, HLA B27 for AS***
How to reduce rate of postop dysphagia after multi level ACDF?
Local steroid to the retropharyngeal area**
Can also by systemic during procedure**
Most common peripheral nerve injury detected by eletrophysiologic monitoring during anterior cervical?
1: Brachial plexopathy following SHOULDER TAPING and counetrtraction*
2: Brachial plexopathy on NECK EXTENSION**
3: ULNAR NEURPATHY is third most common* (from malpositioned UE’s)*
% of peds patients with concurrent spinal column injury after trauma (Pt transferred with known T6 burst fx)
30-55%
Mortality risk of type II odontoid in elderly with surgery vs nonop?
Surgery = 1 year mortality of 14%
Nonsurgical: 1 year mortality of 26%***
Worst prognosis for cervical myelopathy patient with what types of changes in cord on MRI?
INCREASED T2, and DECREASED T1***
