The assessment of vertebral deformity: A method for use in population studies and clinical trials

Abstract

The absence of specific criteria for the definition of vertebral fracture has major implications for assessing the apparent prevalence and incidence of vertebral deformity. Also, little is known of the effect of using different criteria for new vertebral fractures in clinical studies. We therefore developed radiological criteria for vertebral fracture in women for assessing both the prevalence and the incidence of vertebral osteoporosis in population and in prospective studies and compared these with several other published methods. Normal ranges for vertebral shape were obtained from radiographs in 100 women aged 45-50 years. These included ranges for the ratios of anterior/posterior, central/posterior and posterior/predicted posterior vertebral heights from T4 to L5. The predicted posterior height was calculated from adjacent vertebrae. In contrast to other methods, our definition of fracture required the fulfillment of two criteria at each vertebral site, and was associated with a lower apparent prevalence of fracture in the control women due to a lower false positive rate. The prevalence and incidence of vertebral deformity using different criteria were then compared in a series of women with skeletal metastases from breast cancer in whom radiographs were obtained 6 months apart. The prevalence of vertebral deformity and the specificity for deformity varied markedly with differing criteria. Using a cut-off of 3 standard deviations the prevalence of vertebral deformity in the women with breast cancer was 46%. Using other methods, the prevalences of deformity ranged from 33% to 74%. Over a 6-month interval 25% of patients with breast cancer sustained 61 deformities using our method, of which only 8% resulted from errors in reproducibility. The number of patients sustaining new deformities was increased twofold when assessed by other methods (45%-53%), but errors of reproducibility may have accounted for 21% of the new deformities. The magnitude and distribution of these errors have important implications for the apparent therapeutic efficacy of agents in clinical trials of osteoporosis. The rapid semi-automated technique for assessing vertebral deformities on lateral spine radiographs that we have developed has a high specificity, and reduces the impact of errors of reproducibility on estimates of prevalence and incidence. The method should prove a value in assessing vertebral deformity both in population studies and in prospective clinical trials.

Impact of prevalent and incident vertebral fractures on utility: results from a patient-based and a population-based sample

“…In EPOS, both baseline and follow-up spinal radiographs (mean = 3.8 years after baseline) were evaluated in a single center (Berlin) [12,22]. Prevalent deformities at baseline were defined morphometrically using the McCloskey-Kanis algorithm [23]. Incident VFX were classified both by qualitative (clinical) radiologist assessment and/or morphometrically.…”

Paraspinal muscle control in people with osteoporotic vertebral fracture

“…Vertebral fractures were identified from standing, lateral radiographs of the thoracic and lumbar spine based on a conservative morphometric deformity criteria. Vertebrae were classified as wedgefractured when anterior vertebral height was reduced ‡30% compared with posterior height in that and the adjacent superior or inferior vertebra, measured using digital image processing software [29]. Qualitative review by a radiologist ensured that compression fractures were not overlooked.…”

The effect of osteoporotic vertebral fracture on predicted spinal loads in vivo

“…Similar to McCloskey et al [39], a vertebral body was classified as 'fractured' when two criteria were fulfilled at each site, to reduce the number of false positives. Vertebrae were classified as wedge-fractured if the H A was reduced by ‡30% compared to its H P and the H P of the adjacent superior or inferior vertebra.…”