A better imaging alternative

Is the recommendation based on six high-risk criteria presented by Holmes et al. (1) the final answer to the question: which patients sustaining thoracolumbar trauma require imaging by plain film radiography? While their result of 100% negative predictive value is invaluable information, their results of 3.9% specificity and 6.6% positive predictive value do not support a conclusive imaging recommendation. This observation, however, does not detract from the authors’ comprehensive research effort, nor from their contribution to the “Best Practice” efforts currently being pursued by many Emergency Physicians and Radiologists. In this study, the authors use an evidence-based approach focusing on input: who requires plain film radiography, based on the presence of high-risk criteria. This is but one approach.

There is another approach currently being investigated by Radiologists. In these studies, the authors use an evidence-based approach focusing on output: who requires multi-detector computed tomography (MDCT), based on the probability of injury and its cost-effectiveness (2). The probability of injury is defined by high-risk criteria similar to those of Holmes et al. as well as the criterion “mechanism of injury” (3). This probability of injury is integrated with cost to determine the cost-effectiveness of MDCT. MDCT has been selected, rather than plain film radiography, for several reasons, which are factored into the cost-effectiveness equation. This new imaging modality, now performed within minutes, affords comprehensive total body scanning, often required by patients sustaining thoracolumbar injury. Compared to plain film radiography, MDCT has enhanced sensitivity and specificity, with less time expended in performance and with images of unequaled technical quality (4). MDCT has been found to be cost-effective in patients when the probability of injury is > 10% (high-risk) and when the probability of injury is > 4% (moderate-risk). In the view of some Radiologists, this approach represents the evolving standard of practice, with a new golden standard of imaging 5, 6. Others identify availability of MDCT as the only issue hindering universal acceptance of this approach. The issue of availability has already been addressed by many Level 1 and Level 2 Trauma Centers.

Does this recommendation of the Radiologists represent the final answer to the diagnosis of thoracolumbar injury? While the “Best Practice” is not yet finalized, as Holmes et al. plan their future study, I am convinced that the critical aspect in achieving this goal is an interdisciplinary approach: the Emergency Physicians defining high-risk, low-risk and moderate-risk criteria; the Radiologists defining the appropriate imaging modality in a given clinical setting; and the Medical Statisticians analyzing these data.