Cervical Spine Fractures: Who Really Needs CT Angiography?

Mitchell S. Fourman, MD, MPhil; Jeremy D. Shaw, MD, MS; Nicholas J. Vaudreuil, MD; Malcolm E. Dombrowski, MD; Rick A. Wawrose, MD; Lorraine A.T. Boakye, MD; Louis H. Alarcon, MD, FACS; Joon Y. Lee, MD; William F. Donaldson III, MD

Disclosures

Spine. 2019;44(23):1661-1667. 

In This Article

Abstract and Introduction

Abstract

Study Design: Retrospective cohort study.

Objective: Compare a novel two-step algorithm for indicating a computed tomography angiography (CTA) in the setting of a cervical spine fracture with established gold standard criteria.

Summary of Background Data: As CTA permits the rapid detection of blunt cerebrovascular injuries (BCVI), screening criteria for its use have broadened. However, more recent work warns of the potential for the overdiagnosis of BCVI, which must be considered with the adoption of broad criteria.

Methods: A novel two-step metric for indicating CTA screening was compared with the American College of Surgeons guidelines and the expanded Denver Criteria using patients who presented with cervical spine fractures to a tertiary-level 1 trauma center from January 1, 2012 to January 1, 2016. The ability for each metric to identify BCVI and posterior circulation strokes that occurred during this period was assessed.

Results: A total of 721 patients with cervical fractures were included, of whom 417 underwent CTAs (57.8%). Sixty-eight BCVIs and seven strokes were diagnosed in this cohort. All algorithms detected an equivalent number of BCVIs (52 with the novel metric, 54 with the ACS and Denver Criteria, P = 0.84) and strokes (7/7, 100% with the novel metric, 6/7, 85.7% with the ACS and Denver Criteria, P = 1.0). However, 63% fewer scans would have been needed with the proposed screening algorithm compared with the ACS or Denver Criteria (261/721, 36.2% of all patients with our criteria vs. 413/721, 57.3% with the ACS standard and 417/721, 57.8%) with the Denver Criteria, P < 0.0002 for each).

Conclusion: A two-step criterion based on mechanism of injury and patient factors is a potentially useful guide for identifying patients at risk of BCVI and stroke after cervical spine fractures. Further prospective analyses are required prior to widespread clinical adoption.

Level of Evidence: 4.

Introduction

Computed tomography angiography (CTA) is used to rapidly screen for blunt vertebral artery injuries (BCVI),[1] which have been associated with devastating and deadly posterior circulation strokes.[2] While the expanded Denver Criteria[3] is widely used as the benchmark for institutional CTA screening criteria, minimal high-quality evidence supports its use.[4] Multiple works argue that the risk of stroke and the complex relationship between BCVI, patient, and injury factors justifies the universal screening of blunt cervical trauma patients to identify all BCVIs.[5–7] However, the low sensitivity of CTAs (< 80% in pooled analyses[8,9]) leads to a high false-positive rate and potentially harmful treatment with anticoagulation if used indiscriminately.[10–13] Optimal CTA efficacy therefore requires judicious patient selection and standardized BCVI diagnostic thresholds.

Existing BCVI screening criteria are largely based on the landmark study by Biffl et al[14] that led to the original Denver Criteria. The American College of Surgeons Committee on Trauma Advanced Trauma and Life Support (ATLS) guidelines mandate CTA screening for any C1–C3 fracture, cervical spine fractures that enter the foramen transversarium, and cervical fracture subluxations,[15,16] without considering mechanism of injury. In contrast, the expanded 2011 Denver Criteria includes nonfracture indications for BCVI screening, such as mandibular fractures and focal neurologic deficits, in addition to the same cervical spine fracture criteria as the ACS standard.[3]

As long-term deficits from BCVIs that do not lead to a stroke are rare,[17] it is critical to identify those lesions likely to cause the posterior circulation strokes that commonly have poor long-term functional outcomes and 25% to 50% mortality rates.[4,10,13] While the goals of current screening criteria are to identify every BCVI, a better goal may be to effectively prevent posterior circulation strokes.[18] Many of the current screening algorithms for BCVI are driven by retrospective studies of high-energy trauma patients. Indeed, in reviewing the works of Biffl and Scott[19,20] no low-energy BCVI progressed to a posterior circulation stroke in either work.

The purpose of the present study is to evaluate a novel two-step algorithm for the use of a CTA by nonspine specialists in the acute trauma setting. Detection rates of BCVI with this novel instrument were compared to the gold standard American College of Surgeons (ACS) or the expanded Denver Criteria. We hypothesized that combining patient factors with fracture characteristics would narrow the indications for a CTA, without missing potentially devastating strokes.

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