Vertebral Fracture Assessment (VFA)

Vance J. Bray, MD

The 2005 American Medical Association Current Procedural Terminology (CPT®) coding manual includes a new CPT code, 76077, for vertebral fracture assessment (VFA) utilizing DXA technology. VFA is the preferred term for what has been called morphometric x-ray absorptiometry (MXA) in the medical literature. VFA is the same as the proprietary terms used by the DXA manufacturers of VFA technology. Instant Vertebral AssessmentTM (IVA) and Radiologic Vertebral Assessment (RVATM) are terms used by Hologic,Inc. for their DXA machines. Dual-energy Vertebral Assessment (DVA), which was previously known as LVA, is used by GE Healthcare Lunar densitometers. The VFA products of both manufacturers are excellent tools to enhance the care provided at bone densitometry centers. The Centers for Medicare and Medicaid Services (CMS) reimbursement for VFA has been set at a national average of about $40. Approval of the new CPT code and CMS reimbursement for VFA are recognition of the clinical significance of identifying prevalent vertebral fractures.

Previous vertebral fracture is a major risk factor for future fragility fracture. The risk for a new vertebral fracture is greatly increased for an individual with a current vertebral fracture compared to one without a previous fracture, even with identical Bone Mineral Density (BMD). The vertebral fracture incidence for a woman with low BMD and no prior vertebral fracture is 70% less than for a woman with low BMD and a prevalent vertebral fracture. A woman with high BMD and a previous atraumatic fracture is actually at greater risk for another vertebral fracture than is a woman with low BMD who has not previously sustained a vertebral fracture. Multiple vertebral fractures markedly increase the risk of future fractures1. The risk of a hip fracture or of other nonvertebral osteoporotic fractures is also increased in an individual with pre-existing vertebral fractures2.

The prevalence of vertebral deformities is estimated at approximately 11 per 100 women 50-59 years old and 54 per 100 in those 80 years of age and older1. However, only 1 in 4 vertebral fractures are clinically recognized2. Radiographic imaging to identify patients with vertebral fractures would require PA and lateral thoracic and lumbar films, resulting in significant expense and radiation exposure. In most settings where DXA is performed conventional x-ray equipment is not available. This makes it impractical to utilize conventional radiographs for the identification of asymptomatic vertebral fractures. AP and lateral VFA images are available with fan beam bone densitometers using special software. Vertebrae from T5 through L4 are imaged and can be analyzed semi-quantitatively and quantitatively by the examiner for the presence of fractures. The VFA image can also be analyzed to determine the grade (severity) of a vertebral fracture according to semi-quantitative analysis of Genant3.

The sensitivity of VFA for detection of fractures has been estimated at 95% and the specificity for excluding them was found to be 82%4. Of patients evaluated with VFA, 13% of the studies could not be interpreted due to scoliosis, scapular or rib shadow, severe arthritic changes or multiple compression fractures with severe spinal deformities. There is good agreement (96.3%) between vertebral fracture identification with DXA and with conventional radiographs analyzed semi-quantitatively5. The sensitivity of VFA for identifying moderate and severe fractures was 91.9% and the negative predictive value was excellent at 98%. The majority of disagreements between VFA and conventional radiographic images were mild wedge and endplate deformities and poor visualization of the upper thoracic vertebrae on DXA scans.

Among 482 postmenopausal women, mean age 72, with no prior knowledge of vertebral fractures who were screened for osteoporosis, 18.3% were found to have a vertebral fracture by VFA6. The sensitivity of BMD alone to identify osteoporosis as compared to diagnosing osteoporosis based upon either low BMD or the presence of a vertebral fracture ranged from 40% (only total hip measured) to 74% (any central site measured). This would suggest that between 26% (any central site measured) and 60% (only total hip measured) of patients could have been misdiagnosed without spinal imaging. Based upon BMD alone and the central site measured, 11-18.7% of women with vertebral fractures would have been classified as normal. Among 297 men and women referred for routine BMD measurement only 11% of the women found to have a fracture gave a history of prior vertebral fracture and only 56% of those with VFA evidence of fracture met BMD criteria for a diagnosis of osteoporosis4.

Lateral spine imaging is clearly a useful tool in identifying individuals for whom treatment to reduce the risk of future fragility fractures is indicated. Criteria for the performance of VFA are being developed by the ISCD VFA Task Force and will be one of the subjects discussed at the 2005 ISCD Position Development Conference in Vancouver, BC, Canada in July. In February 2005, the ISCD Annual Meeting in New Orleans will offer the completely updated Bone Densitometry Course including newly incorporated one-hour VFA introductory lectures for clinicians and technologists. A newly developed four-hour advanced VFA educational course will also be offered on Wednesday afternoon prior to the Annual Meeting.

References
1. Melton LJ III, Lane AW, Cooper C, et al. Prevalence and incidence of vertebral deformities. Osteoporosis Int 1993;3:113-9.
2. Ross PD, Davis JW, Epstein RS, et al. Pre-existing fractures and bone mass predict vertebral fracture incidence in women. Ann Intern Med 1991;114:919-23.
3. Genant HK, Li J, Wu CY, et al. Vertebral fractures in osteoporosis: a new method for clinical assessment. J Clin Densitom 2000;3:281-90.
4. Vokes TJ, Dixon LB, Favus MJ. Clinical utility of dual-energy vertebral assessment (DVA). Osteoporosis Int 2003;14:871-8.
5. Rea JA, Li J, Blake GM, et al. Visual assessment of vertebral deformity by x-ray absorptiometry: a highly predictive method to exclude vertebral deformity. Osteoporosis Int 2000;11:660-8.
6. Greenspan SL, von Stetten E, Emond SK, et al. Instant vertebral assessment. A non-invasive dual x-ray absorptiometry technique to avoid misclassification and clinical management of osteoporosis. J Clin Densitom 2001;4:373-80.

Last modified: December 17, 2012