Osteoporotic Vertebral Compression Fracture - Spine

Introduction
A fragility fracture of the spine 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 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 Prognosis mortality 1-year mortality ~ 15% (less than hip fx) 2-year mortality ~20% (equivalent to hip fx)
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 Diagnosis
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