Injuries to the Cervical Spine

Initial Evaluation and Physical Examination

Given the high incidence of C-spine injury and the potentially devastating consequence of SCI, first responders and clinicians must maintain a high index of suspicion in all trauma patients. Patients at risk for spine injuries should be immobilized until an appropriate and thorough evaluation of the spine for fractures or instability is completed. The most common method of full spine immobilization includes the application of an appropriately sized rigid cervical collar together with supportive blocks fastened against a hard backboard. Immobilization should be initiated at the trauma scene and maintained during triage, resuscitation, and primary and secondary surveys. In patients improperly immobilized, the primary survey and airway manipulation can theoretically exacerbate existing cervical spine injuries, although there is new evidence that suggests the risk may be overestimated.

The primary trauma survey places special emphasis on airway, breathing, and circulation (ABCs of resuscitation) and are geared toward rapid identification and rectification of acute life-threatening issues. In addition, appropriate management of the ABCs to maintain adequate ventilation, oxygenation, and tissue perfusion serve to prevent secondary injury to an injured spinal cord. During airway evaluation, care should be taken to avoid excess manipulation of the cervical spine even if a rigid collar has been applied. Hyperflexion/extension can occur during dynamic maneuvers to open the airway or during laryngeal intubation. The provider should consider the potential for difficult airway management and have appropriate expertise and equipment available. The use of video laryngoscope-guided intubation or laryngeal mask airway should be considered.

During the secondary survey, the patient should be logrolled to allow examination of the spine. The spine is palpated for evidence of swelling, deformity, step-off, and tenderness. A detailed neurologic exam should be performed. In the awake patient, a motor and sensory exam is carried out with the aim of identifying the level of injury if one exists. Testing of different sensory modalities may provide information regarding the nature of the injury (eg, Brown-Séquard syndrome with selective loss of pain sensation and proprioception). The obtunded patient may be observed for spontaneous movement in the extremities or in response to central stimuli as evidence of gross motor function. Motor movements in the extremities in response to peripheral painful stimuli should be carefully distinguished from reflex movements that do not require corticospinal input. Testing of rectal tone is mandatory in all patients with suspected spinal cord injury. Eliciting the bulbocavernous reflex is useful for prognostication. In the setting of paralysis following spinal cord injury, absence of the reflex indicates the presence of spinal shock and precludes a definitive statement about completeness of a spinal cord injury. In contrast, the presence (or return) of the reflex signifies the absence (or resolution) of spinal shock, rendering significant improvement in neurologic function less likely. Priapism is another sign of spinal cord injury and signifies the acute loss of spinal sympathetic input to the pelvic vasculature. In acute C-spine injury with significant cord involvement, flaccid paralysis with diminished deep tendon reflexes is common; hyperreflexia, positive Babinski reflexes, and other upper motor neuron signs are less frequent.

Accurate documentation of the patient's neurologic exam is important and serves as a baseline to monitor treatment, allow detection of acute deterioration, and provide prognostic information. At our institution, the American Spinal Cord Injury Association (ASIA) International Standard Neurological Classification is utilized to document the level of injury, motor score, and ASIA Impairment Scale ( Fig. 29.1 ). This assessment scale permits accurate, consistent, and reproducible measures of the patient's neurologic status. In the awake patient without focal neurologic deficit, it is appropriate to attempt clinical C-spine clearance to facilitate early discontinuation of spine immobilization (discussed later). Clearance of the C-spine facilitates the diagnosis and treatment of other injuries and has been shown to reduce complications, including soft tissue pressure injuries and respiratory complications.

Clearing the C-Spine and Radiographic Imaging

An important part of any trauma workup is the evaluation for possible C-spine injuries. Before C-spine injuries are excluded, the patient is kept immobilized. It is important to make a thorough assessment and exclude cervical spine injuries as soon as possible in order to expedite the removal of C-spine immobilization and hard collar. This is advantageous, as C-spine immobilization may interfere with venous outflow and increase intracranial pressure (ICP). Immobilization often causes airway compromise and prevents dynamic maneuvers necessary to facilitate adequate ventilation and positioning for airway management. In the trauma patient, the cervical collar can be a further source of agitation, and a suboptimally applied collar is not an infrequent cause of skin breakdown.

In the awake and asymptomatic patient, the C-spine may be cleared clinically if the following criteria are met : (1) the patient is fully awake and oriented, and his or her mental status is not affected by substances or medication; (2) there is an absence of focal neurologic deficits (3) the patient denies neck pain or posterior midline tenderness (4) an absence of distracting pain from significant associated injuries and (5) on clinical examination the patient has nonpainful normal range of movement. In such a patient, cervical immobilization is unnecessary and if applied, the cervical collar may be safely removed without imaging. In patients who sustained penetrating brain injury, most commonly GSW, evidence has shown that unless the trajectory suggests direct injury to the C-spine, immobilization is not necessary. In the awake patient in whom the C-spine cannot be clinically cleared and, similarly, in obtunded patients, thin cut computed tomography (CT) spanning the occiput to the top of T1 in sagittal, axial, and coronal views is the initial imaging modality of choice. CT provides superior imaging resolution compared to plain film radiograph and is widely available in modern trauma centers, with a sensitivity of 99% and a specificity of 100%. Furthermore, three-dimensional reconstruction of the cervical spine can be useful in the evaluation of complex spine injuries and operative planning. When CT is not immediately available, plain film lateral, anteroposterior, and open-mouth odontoid views have a 92% sensitivity and a 99% negative predictive value.

For patients whose C-spine cannot be clinically cleared, including awake patients with neck pain or midline cervical tenderness, or obtunded patients, in the setting of a normal thin-cut C-spine CT, cervical immobilization should be continued until (1) the symptoms resolve, (2) adequate dynamic flexion/extension plain films exclude cervical instability, (3) there is normal magnetic resonance imaging (MRI) of the C-spine, or (4) the treating physician elects to discontinue immobilization based on balanced assessment of injury severity, clinical risk, and the effects of immobilization on other care requirements. The rationale is the low but real possibility of an occult injury resulting in neurologic deterioration. Plain radiographs of the C-spine with dynamic flexion-extension views under physiologic axial loading in the upright position are useful to evaluate C-spine stability and reveal the presence of subluxations or abnormal ligamentous laxity. However, the utility of flexion-extension x-rays in obtunded patients is limited, and they are no longer recommended and should be performed in awake patients. MRI allows for the evaluation of soft tissue integrity that cannot be visualized on plain radiograph or CT. It permits evaluation of the discoligamentous complex, the integrity of the spinal cord, and evidence of cord injury, as well as the exclusion of compressive lesions such as an expanding epidural hematoma. Following this algorithm, at our institution, unless there is a high index of suspicion, the C-spine is cleared for the acutely ill polytrauma patient following adequate thin-cut CT combined with physical examination demonstrating symmetric motor movements without obvious neurologic deficit. This approach is particularly important in polytrauma patients with coexisting head injury when there is a concern for raised ICP. C-spine clearance facilitates cervical hard collar removal and head-of-bed positioning to promote venous outflow. In patients for whom a high index of suspicion exists—for example, a patient who has a paucity of extremity movements out of keeping with the extent of head injury—an MRI is obtained once the patient is deemed stable to tolerate imaging. Indeed, a review by the Spine Trauma Study Group of missed spine fractures at eight level 1 trauma centers has identified rare cases where neurologic deterioration was attributable to injury missed by plain radiograph and CT but that was evident on MRI. Interestingly, a large-scale meta-analysis of the literature including more than 1718 subjects supports proceeding to removal of cervical immobilization following a negative C-spine CT.

On the other hand, any patient with a focal neurologic deficit that raises concern for a cervical spine injury should remain immobilized until CT and MRI of the spine adequately exclude bony, ligamentous, and cord injuries. Furthermore, C-spine fracture is an indication for radiographic evaluation of the entire axial spine, as in 8% to 14% of cases, C-spine injury is associated with injury in other parts of the axial spine. Although MRI of the C-spine is not always indicated in cervical fractures, it is often informative in cases associated with neurologic deficits and in cases that raise concern for cord compression from discoligamentous complexes or hematomas that are suboptimally visualized on CT. MRI is also indicated in patients with underlying cervical spine pathologies such as ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis. Patients with such underlying pathologies are more likely to have significant injury following trivial trauma, have complex type injuries, and develop complications such as epidural hematoma. Blunt cerebrovascular injury involving the vertebral and carotid arteries may be associated with cervical spine injuries, particularly injuries involving C1 and C2 or injuries resulting in significant subluxation or displacement of adjacent vertebral bodies. Neck CT angiography should be performed to assess vascular structures and exclude injuries.

Closed Reduction of Cervical Spine Fracture-Dislocations

Following initial clinical evaluation and appropriate imaging, a decision should be made regarding whether early closed reduction of the spine fracture-dislocation is indicated. Closed traction reduction of posttraumatic subluxation and facet dislocations facilitates the restoration of normal spine alignment and in the majority of cases significantly reduces spinal cord compression. In reported series, closed reduction is achieved in 70% to 80% of patients. Although class 1 evidence is lacking, the rationale is that early reduction of cord compression prevents secondary injury and leads to improved neurologic outcome. Indeed, there are numerous case reports of rapid neurologic improvement following closed reductions. Furthermore, fracture-dislocation reduction is often associated with symptomatic relief for the patient.

Cervical fracture-dislocations can result in disk bulge and herniation and may be present in over half of patients. A concern with closed reduction is the potential for ventral cord compression with a herniated disk, resulting in the worsening of neurologic deficits. In the awake patient, the reported incidence of neurologic deterioration following closed reduction is low, in the order of 1%, and the utility of a prereduction MRI is limited. In cases where a herniating calcified discoligamentous complex is observed on CT, MRI may be useful, and a decision may be made to forego closed reduction, opting instead for open reduction under direct vision in the operating room. Similarly, in the unconscious patient or patients who cannot cooperate with neurologic evaluation during traction reduction, prereduction MRI is indicated, followed by open or closed reduction.

In a busy trauma center, provision and protocol should be in place for closed cervical traction reduction. Given the potential benefit of early reduction and risk of further neurologic injury due to an unstable spine fracture, reduction should be performed urgently after the patient has been stabilized. At our institution, cervical traction takes place in the preanesthesia care unit (PACU) and involves multiple disciplines, including spine surgery, anesthesia, and radiology ( Fig. 29.2 ). After informed consent is obtained, the patient is taken to the PACU and the anesthesia team readies the patient with light sedation. The patient is placed in a slight reverse Trendelenburg position. Local anesthetic is injected, and MRI-compatible Gardner-Wells tongs are placed an inch above the ear and slightly posterior of the external auditory meatus and tightened appropriately. A baseline neurologic exam and fluoroscopy image are obtained. The pin positions and axis of traction distract and flex the cervical spine and, in the case of jumped facets, promote dis-impaction of the jumped superior facet over the inferior facet. Traction weights are added in 5-pound increments while an assistant provides countertraction through wrist restraints from the foot of the bed. Fluoroscopy is used to evaluate reduction, and weights are added at approximately 5-minute intervals until the spine is reduced, with ongoing neurologic exam as weights are added. The maximum weight that can be safely applied is unknown, but the general rule is to use 10 pounds for occiput and 5 pounds for each vertebral level (ie, ~20 pounds for C1–C2 and 40 to 50 pounds for subaxial cervical spine). Weights up to 80% of body weight or 150 pounds have been used without adverse event in several studies. Traction reduction should be abandoned if the patient experiences a worsening of neurologic symptoms or failure of reduction with maximum weight and adequate distraction (1 cm). Once reduction has been achieved, 10 to 20 pounds are usually sufficient to maintain reduction. The patient then proceeds to MRI, maintaining traction and alignment in the scanner, followed by transfer to the operating room for definitive management if required. The transfer of the patient between traction tables should be carefully coordinated, as there is significant risk of repeat dislocation, and should be supervised by an experienced spine surgeon.

Intensive Care Management of Cervical Spinal Cord Injuries

The primary goals in management of cervical spinal cord injuries are (1) preservation and restoration of neurologic function, (2) correction and prevention of biomechanical instability and deformity, (3) management of distressing symptoms, and (4) prevention of complications. To these ends, acute management includes the prevention of secondary neurologic injuries, stabilization of the spine by immobilization or surgical intervention, aggressive treatment of pain symptoms, and active prevention of potential complications. The medical needs of C-spine injury patients are thus numerous and complex; as such they should be managed in an intensive care unit that incorporates a multidisciplinary approach involving surgeons, intensivists, and rehabilitation specialists. Patients often have other injuries requiring close cardiopulmonary monitoring and treatment. Many level 1 trauma centers have established high-volume acute spinal cord injury centers that offer both excellence and expertise. There is evidence that patient outcome is significantly improved when managed in such centers.