Vertebral Augmentation vs Nonsurgical Therapy

Abstract

Vertebral fractures are themost common clinical manifestation of osteoporosis. In the United States alone, approximately550 000 individual experienceavertebral fractureeach year, resulting insignificantpainandshort-termdisability.1The morbidity caused by symptomatic vertebral fractures is reflected by the more 150 000 hospitalizations per year. Established risk factors for vertebral fracturesmirror those for factures at other sites and include advanced age, lower bone mineral density, falling, smoking, and inadequate calcium intake. An extremely important point for patients and clinicians is that a vertebral fracture is a very strong predictor of subsequent fractures, both vertebral and nonvertebral. Most clinical guidelines recommend pharmacologic therapy, regardless of bone mineral density, in an older individual with a new vertebral facture. Given the substantialmorbidity associatedwith acute vertebral facture, there is little surprise that therehasbeensomuch enthusiasm for vertebral augmentation. Vertebral augmentation is an invasive procedures designed to “fix” acute vertebral fracturesviapercutaneousinjectionofcementinto1ormore fractured vertebra, thereby renderingthemimmobileand perhaps restoring some biomechanical integrity. Vertebral augmentation includes bothvertebroplasty,wherecement is injected under pressure into the fractured vertebra, and kyphoplasty, where cement is introduced into a cavity created by the inflation of a balloon placed within the fractured vertebral body. Vertebral augmentation is generally safe, but extravasationof cement or othercomplicationscanoccur, sometimewith fatal results.2Although vertebral augmentation can be performed on outpatients, it is often used in hospitalized patients with acute debilitating vertebral factures. It is worth noting that most vertebroplastyproceduresareperformedbyradiologists,while most kyphoplasty procedures are performed by nonradiologists (particularly orthopedists), and the number of proceduresperformedintheUnitedStatesalone is impressive:nearly 25 000vertebroplastyand48 000kyphoplastyprocedureswere performed and billed toMedicare in 2010.3 Unfortunately, theevidencesupporting theefficacyofvertebral augmentation to improve symptomatic outcomes after acute osteoporotic vertebral fracture is mixed. Although uncontrolled studies have consistently demonstrated reduced short-term pain and disability after vertebral augmentation, randomized trial results have been inconsistent. In particular, 2 blinded sham-controlled trials of vertebroplasty showed no significant benefit on self-reported pain or function after 1 month of follow-up.4 Conversely, a randomized but unblinded industry-supported trial of kyphoplastywithout sham controls found that, comparedwith conservative therapy, kyphoplasty treatment improved pain and function scores at 6 and 12months of follow-up, but by 24months the differences wereattenuatedandmostlynonsignificant.5Todate,noshamcontrolled trials of kyphoplasty have been reported, leading to speculation that someor all of the subjective improvement observed in observational studies and unblinded trialsmight be attributable to the placebo effect.2 In addition topain anddisability, somestudieshavedocumented that osteoporotic fractures, particularly of thehip, are associatedwithan increase inpostfracturemortality.Thereare considerably fewer data about the relationship between vertebral fracture and mortality, but several studies have suggested thatmortality is increasedamong individualswithvertebral fracture even after accounting for the effects of age, comorbidities, and other factors. For example, 1 study found that totalmortalitywas 23%higher (95%CI, 10%-37%) among older women with documented vertebral fracture.6 Although the precise cause of death is often difficult to ascertain in large observational studies, this study found that pulmonary deaths were significantly more common among women with documented vertebral fractures. The observation that vertebral fractures may be associatedwithrespiratorycompromiseand increasedmortality logically leads to the hypothesis that interventions that mitigate the symptoms and biomechanical effects of vertebral fractures could potentially reduce postfracture mortality. Because existing trials are much too small to examine survival as an outcome, several studies have used administrative data toanalyze theprospective relationshipbetweenvertebral augmentation and mortality. A frequently quoted study by Edidin et al,7 funded by a company that manufactures kyphoplasty equipment, analyzed the prospective relationship between use of vertebral augmentation andmortality among Medicare enrollees from 2005 to 2008. After accounting for baseline differences in age, health status, and 12 common comorbiditiesusingmultivariatemethods, they found that compared with patients who received nonsurgical management, totalmortalitywas reducedby24%(95%CI, 23%-25%)and44% (95% CI, 43%-45%) among those who received vertebroplasty and kyphoplasty, respectively. In this issue of JAMA Internal Medicine, McCullough and colleagues8 use several approaches to address the question of mortality following vertebral augmentation. Similar to Edidin et al,7 McCullough and colleagues studied the prospective relationshipbetweenvertebralaugmentationandmortalityusing Medicareadministrativedata.Because these investigatorswere concerned thatunaccounted-fordifferences inbaselinehealth CMEQuiz at jamanetworkcme.com and CMEQuestions page 1564