Worldwide, spinal cord injury (SCI) occurs with an annual incidence of 15 to 40 cases per million [I]. In the United States, approximately 11,000 incident cases of SCI occur each year [2], and the annual prevalence is estimated to be 253,000 persons. According to the National Spinal Cord Injury Database, the average age of injury has increased as the median age of the general population of the United States has increased. As of 2000, the average age of injury was 38 years, and the percentage of persons over 60 years of age increased from 4.7% before 1980 to 11.5% among injuries occurring since 2000. Among incident cases, 77.8% of SCIs occur among males. Blunt mechanisms of injury, such as motor vehicle crashes, account for 46.9% of SCIs, followed by falls, acts of human violence (eg, gunshot wounds and assaults), and sports-related injuries [3]. Penetrating trauma accounts for approximately 10% to 20% of spinal injuries [4]. Although lifetime costs attributable to SCI depend on the age, level, and severity of injury, estimates range from $472,000 to $2,924,000 [3]. According to a systematic review performed by Sekhon and Fehlings [1], 55% of all spine injuries involve the cervical spine, with a lesser but approximately equal percentage involving the lumbosacral (15%), throracolumbar (15%), and thoracic (15%) regions, respectively. Spinal cord injury without radiographic abnormality (SCIWORA) is defined as the presence of neurologic deficits in the absence of an apparent injury on a complete, technically adequate plain radiographic series. The injury pattern has been attributed to various causes, including ligamentous injuries, disc prolapse, and cervical spondylosis. SCIWORA is reported more commonly among the pediatric population, and it accounts for up to two thirds of severe cervical injuries in children under 8 years of age [5]. However, SCIWORA is not uncommon among middle-aged and elderly patients, accounting for up to 12% of cases of adult SCI [6]. In fact, in a subanalysis performed on the large database of the National Emergency X-radiography Utilization Study (NEXUS), only 27 of the 818 total patients with cervical spine injury were diagnosed with SCIWORA, none of whom were children despite the inclusion of over 3000 pediatric patients [7]. According to the National Spinal Cord Injury Resource Association Center, 45% of all injuries are classified as complete injuries, which result in total loss of sensation and function below the injury level. Overall, a little more than 50% of the injuries result in quadriplegia [8]. Although all SCI patients can improve from the initial classification of having a complete or incomplete injury, no more than 0.9% of patients fully recover. In fact, many SCI patients suffer progressive neurologic deterioration due to myelomalacia, syrinx formation, progressive cord compression, or cord tethering due to adhesions [4]. Early diagnosis and management of SCI is critical in minimizing complications and the severity of injury. This article reviews the test characteristics and evidence-based indications for imaging modalities of SCI.
