Osteoporotic Vertebral Compression Fracture - Spine

summary
- Osteoporotic Vertebral Compression Fractures are very common fragility fractures of the spine that affect up to 50% of people over 80 years old.
- Diagnosis can be made with lateral radiographs. Determining the acuity of a fracture requires an MRI or bones scan.
- Treatment is usually observation and pain management. Kyphoplasty is reserved for patients with recalcitrant symptoms after nonoperative treatment for 4-6 weeks fails. Assessment and management of osteoporosis is indicated in the presence of these injuries.

Epidemiology
- Incidence
  - vertebral compression fractures (VCF) are the most common fragility fracture
  - 700,000 VCF per year in US
  - 70,000 hospitalizations annually
  - 15 billion in annual costs
- Demographics
  - affects up to
    
    25% people over 70 years
    
    50% people over 80 years
- Risk factors
  - history of 2 VCFs
    
    is the strongest predictor of future vertebral fractures in postmenopausal women

Etiology
- Pathoanatomy
  - osteoporosis
    
    characteristics
    
    bone is normal quality but decreased in quantity
    
    cortices are thinned
    
    cancellous bone has decreased trabecular continuity
    
    bone mineral density in the lumbar spine (BMD)
    
    peaks at
    
    between 33 to 40 yrs in women
    
    between 19 to 33 years in men
    
    peak BMD is widely variable based on demographic factors and location in body
    
    decreases with age following peak mass
    
    correlate well with bone strength and is a good predictor of fragility fracture
    
    definition
    
    WHO defines osteoporosis as T score below -2.5
- Associated conditions
  - compromised pulmonary function
    
    increased kyphosis can affect pulmonary function
    
    each VCF leads up to 9% reduction in FV
    
    increased risk of mortality from pulmonary dysfunction

Presentation
- Symptoms
  - pain
    
    25% of VCF are painful enough that patients seek medical attention
    
    pain usually localized to area of fracture
    
    but may wrap around rib cage if dermatomal distribution
- Physical exam
  - focal tenderness
    
    pain with deep palpation of spinous process
  - local kyphosis
    
    multiple compression fractures can lead to local kyphosis
  - spinal cord injury
    
    signs of spinal cord compression are very rare
  - nerve root deficits
    
    may see nerve root deficits with compression fractures of lumbar spine that lead to severe foraminal stenosis

Imaging
- Radiographs
  - obtain radiographs of the entire spine (concomitant spine fractures in 20%)
  - will see loss of anterior, middle, or posterior vertebral height by 20% or at least 4mm
- CT scan
  - usually not necessary for diagnosis
  - indications
    
    fracture on plain film
    
    neurologic deficit in lower extremity
    
    inadequate plain films
- MRI
  - usually not necessary for diagnosis
  - useful to evaluate for
    
    acute vs chronic nature of compression fracture
    
    injury to anterior and posterior ligament complex
    
    spinal cord compression by disk or osseous material
    
    cord edema or hemorrhage

Studies
- Laboratory
  - a full medical workup should be performed with CBC, BMP
  - ESR may help to rule out infection
  - Urine and serum protein electrophoresis may help rule out multiple myeloma

Differential
- Metastatic cancer to the spine
  - must be considered and ruled out
  - the following variables should raise suspicion
    
    fractures above T5
    
    atypical radiographic findings
    
    failure to thrive and constitutional symptoms
    
    younger patient with no history of fall

Treatment
- Nonoperative
  - observation, bracing, and medical management
    
    indications
    
    majority of patients can be treated with observation and gradual return to activity
    
    PLL intact (even if > 30 degrees kyphosis or > 50% loss of vertebral body height)
    
    technique
    
    if the fracture is less than five days old
    
    calcitonin can be used for four weeks to decrease pain
    
    medical management can consist of bisphosphonates
    
    to prevent future risk of fragility fractures
    
    some patients may benefit from an extension orthosis
    
    although compliance can be an issue
- Operative
  - vertebroplasty
    
    indications
    
    controversial
    
    AAOS recommends strongly against the use of vertebroplasty in 2011 but then changed their stance in 2014 based on recent studies
    
    outcomes
    
    randomized, double-blind, placebo-controlled trials have shown no beneficial effect of vertebroplasty
    
    vertebroplasty has higher rates of cement extravasation and associated complications than kyphoplasty
  - kyphoplasty
    
    indications
    
    patient continues to have severe pain symptoms after 6 weeks of nonoperative treatment
    
    AAOS recommend may be used, but recommendation strength is limited
    
    technique
    
    kyphoplasty is different than vertebroplasty in that a cavity is created by balloon expansion and therefore the cement can be injected with less pressure
    
    pain relief thought to be from elimination of micromotion
  - surgical decompression and stabilization
    
    indications
    
    very rare in standard VCF
    
    progressive neurologic deficit
    
    PLL injury and unstable spines
    
    technique
    
    to prevent possible failure due to osteoporotic bone
    
    consider long constructs with multiple fixation points
    
    consider combined anterior fixation

Techniques
- Kyphoplasty vs. vertebroplasty
  - performed under fluoroscopic guidance
  - percutaneous transpedicular approach used for cannula
  - vertebroplasty
    
    PMMA injected directly into cancellous bone without cavity creation
    
    performed when cement is more liquid
    
    requires greater pressure because no cavity is created
    
    increased risk of extravasation into spinal canal is greater
  - kyphoplasty
    
    cavity created with expansion device (e.g., balloon) prior to PMMA injection
    
    performed when cement is more viscous
    
    may be possible to obtain partial reduction of fracture with balloon expansion

Complications
- Neurological injury
  - can be caused by extravasation of PMMA into spinal canal
    
    higher risk with vertebroplasty than kyphoplasty
    
    important to consider defects in the posterior cortex of the vertebral body
- Vertebral body osteonecrosis (aka Kummell's disease)
  - Delayed post-traumatic osteonecrosis

Prognosis
- Mortality
  - 1-year mortality ~ 15% (less than hip fx)
  - 2-year mortality ~20% (equivalent to hip fx)

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T