Cervical Burst Fractures

h1 class=”calibre8″>12 Cervical Burst Fractures

Scott C. Wagner and Alan S. Hilibrand

Abstract

Subaxial cervical burst fractures occur relatively infrequently but are typically associated with a high rate of instability and neurological injury. Emergency evaluation, radiographic diagnosis, early classification, and appropriate surgical intervention—which may vary depending on the type of fracture and associated injuries—can yield overall good outcomes. This chapter will examine the evaluation, classification, and treatment options for subaxial cervical burst fractures. Patient characteristics and fracture patterns should be considered when determining the appropriate course of intervention; the treating surgeon’s judgment is also paramount for successful management of these rare injuries.

Keywords: cervical burst fracture, Subaxial Injury Classification (SLIC), AOSpine Subaxial Cervical Spine Classification

12.1 Introduction

Subaxial cervical burst fractures are relatively uncommon injuries, with estimated incidence of 5 to 10% of all burst fractures. ¹ Burst fractures were originally described in the early 1960s as injuries caused by herniation of the intervertebral disc through the endplate of the vertebral body. ² Denis expanded upon this description, utilizing the three-column concept of spinal stability to define burst fractures as disruption of the anterior and middle columns, often with retropulsion of the middle column fragment into the spinal canal; though this description was specific for thoracolumbar fractures. ³ Historically, cervical burst fractures were also described as “teardrop” or “quadrangular” fractures, ⁴^,⁵ and were believed to result from compressive forces along the vertical orientation of the cervical spine due to an axial load. ⁶ In their 2002 article describing treatment techniques, Fisher et al defined this fracture subtype as a “coronal split through the vertebral body, with dorsal displacement of the remaining vertebral body that leads to narrowing of the spinal canal.” ⁵ The flexion movement cause by the axial force often disrupts the posterior ligamentous complex, resulting in significant instability at the injured level with a high risk of neurological compromise. ⁷

Over the past decade, several classification systems have been described and validated, such as the Subaxial Injury Classification (SLIC) System and the AOSpine Subaxial Cervical Spine Injury Classification System. These have been developed in an attempt to standardize treatment protocols for spinal trauma. ⁸^,⁹ Considered in the context of these classification schemes, cervical burst fractures can be systematically evaluated and potential treatment options can be considered based on current evidence. However, no universal treatment algorithm is available at present. Treatment options include conservative care with immobilization in patients without neurological deficits and no evidence of discoligamentous instability, an anterior corpectomy with strut grafting, a posterior cervical decompression and fusion, or a combination of these approaches for severely unstable injuries. ⁶^,⁷

12.2 Initial Evaluation

12.2.1 Clinical History and Physical Examination

Despite comprising only 3% of all blunt trauma, injury to the cervical spine is often among the most catastrophic injuries due to the frequency of associated spinal cord injury. ⁷^,¹⁰ Upon initial presentation, any patient sustaining major trauma or suspected cervical spine injury should be managed according to Advanced Trauma Life Support (ATLS) principles, including protection of the airway and maintenance of circulation and breathing. ⁷ Inspection and palpation of the neck may reveal significant pain or gross deformity, and the cervical spine should immediately be protected in a hard collar (though these are typically placed in the field at the point-of-contact by first responders). With cervical immobilization in place, the patient should be log rolled to allow for inspection and palpation of the entire spinal column. ⁷ A thorough neurological examination, including sensory and motor evaluation, should be performed to identify any deficits, which can be used to determine the potential for spinal axis injury. After appropriate resuscitation has begun, the patient should undergo radiographic evaluation to screen for potential diagnoses on the basis of suspected type of injury.

12.2.2 Radiographic Evaluation

There is some controversy with regard to the use of plain films, including anteroposterior, lateral, open-mouth odontoid, and flexion-extension views of the cervical spine, ⁷ which is primarily related to differences in imaging capabilities across various institutions. Traditionally, plain radiographs were utilized to evaluate global alignment of the cervical spine, including areas of kyphosis or dislocation, as well as for changes in disc height or interspinous distance suggestive of flexion-distraction injuries. ⁷ However, some recent studies have suggested that the sensitivity of plain films to rule out cervical fractures or instability secondary to ligamentous injury ranges from 30 to 60%, and a paper by Sim et al ¹¹ found that 95% of flexion-extension views were inadequate due to the inability to visualize T1 or poor patient effort. ¹²^,¹³^,¹⁴ Therefore, use of computed tomography (CT) imaging has become more common to provide rapid, high-quality screening for traumatic injuries, including the cervical spine. CT scans allow for much better evaluation of the occipitocervical and cervicothoracic junctions than traditional plain radiographs. ⁷ If a cervical burst fracture is identified on a CT scan, magnetic resonance imaging (MRI) has very high utility in evaluating associated discoligamentous and soft-tissue injuries. However, some recent literature has suggested that MRI may not be as reliable in identifying disruption of the posterior ligamentous complex (PLC), which has significant implications with regard to classification and treatment of these injuries. ¹⁵