Surgical Treatment Of Spinal Injury

Surgical Treatment of Spinal Injury

Daniel R. Fassett

James S. Harrop

Traumatic injuries to the spinal column are common events, with more than 50,000 fractures to the spinal column occurring annually in the United States (1). Spinal injury remains a heterogeneous group of injuries and therefore various strategies are employed in their treatment. Multiple clinical variables must be addressed, including the degree of ligamentous and bony injury, the presence of neurologic deficits, perceived patient compliance, and overall health status; these factors are used to determine how the injuries are treated. Treatment can range from simple limitation in activity to external orthosis to open reduction and internal fixation with spinal instrumentation. The goal of treating these injuries is to utilize the least invasive surgical technique to stabilize the injured segment while limiting the potential for subsequent catastrophic neurologic injury, progression of a deformity, and chronic pain conditions. These surgical goals are also tempered by other medical management issues that focus on minimizing hospitalization and immobilization and maximizing the benefits of early and aggressive rehabilitation.

Historical Perspective of Spinal Injury Treatment

Treatment of traumatic spinal injuries was first recorded by Hippocrates (460-370 BCE) who used traction devices to obtain spinal reduction and advocated external stabilization and immobilization. Surgery was not considered a viable option at this time because of the high mortality of surgical techniques, and the presence of neurologic deficits in the setting of spinal trauma was deemed universally fatal. Surgical decompression for the treatment of traumatic spinal cord injury was initially popularized by Paulus of Aegina (625-690 CE) but was not universally accepted because of very poor surgical outcomes at the time. In 1646, Fabricius Hildanus performed the first documented open reduction of a spinal fracture (2, 3, 4, 5, 6 and 7).

It was not until the advent of spinal instrumentation in the 1950s that a more aggressive surgical approach was favored in the treatment of spinal column injuries. Before the development of spinal instrumentation, there was a bias toward conservative treatment, which often involved

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long periods of immobilization (4 to 8 weeks commonly) typically with traction to restore the spinal alignment and allow the fractures time to heal (8). These long periods of immobilization were associated with significant medical complications including pneumonia, deep vein thrombosis, and decubitus ulcers. The use of spinal instrumentation provided surgeons the ability to restore immediate stability to the spinal column, thus allowing for earlier mobilization and fewer complications from prolonged immobilization. In addition, spinal instrumentation theoretically improved fusion rates by providing a stable environment of bone healing, thus reducing the risks of late neurologic deterioration due to spinal instability, progressive spinal deformity, and associated axial back pain syndromes. Even with improvements in instrumentation, it was realized that all instrumentation will fail eventually unless a bony fusion is achieved and, therefore, arthrodesis remains a critical part of all spinal stabilization surgeries (4,6).

Clinical and Radiographic Evaluation of the Trauma Patient

The treatment of spinal trauma consists of an assessment of the traumatic injury through a detailed neurologic examination, physical examination, and then a radiographic evaluation. Radiographic evaluation often begins with plain radiographs followed by supplemental imaging of questionable areas of injury. Although modern imaging techniques have greatly aided in the diagnosis of fractures, determination of ligamentous instability with imaging alone is still unproven even with techniques designed to evaluate the soft tissues such as magnetic resonance imaging (MRI) (9).

Cervical Spine Evaluation

Any trauma patient should immediately be placed in cervical spine immobilization when assessed by emergency medical services (EMS) in the field. Any nonintoxicated patient without neck pain, neurologic deficits, and distracting injuries (injuries to other portions of the body that could potentially mask the pain associated with spinal injury) can be cleared of cervical spine injury with a normal clinical examination alone (i.e., showing no neck pain over a full range of motion of the cervical spine) (10). Neurologically intact patients with neck pain or tenderness are usually assessed with three view (anteroposterior [AP], lateral, and open-mouth odontoid views) plain radiographs as initial assessment (11). If these plain radiographs are normal, these patients are often kept in cervical collar immobilization for 1 to 2 weeks and then should have delayed passive cervical flexion and extension imaging to assess for potential occult ligamentous injury. Although the prevalence of occult ligamentous injury in the setting of normal radiographs is small, the delay in the follow-up flexion/extension imaging can minimize false negative results by allowing muscle spasm to subside. In the neurologically intact patient with severe neck pain and normal plain radiographs, computed tomography (CT), and possibly MRI should be considered to rule out an occult fracture or herniated disc not seen on the plain radiographs (11).

In comatose, obtunded, or intoxicated/sedated patients, where an adequate neurologic examination cannot be obtained, plain radiographs or CT scan are standard in most trauma protocols. With the increase in speed and resolution of multidetector helical CT scanning, this modality is becoming more popular for evaluating multitrauma patients in a time-efficient manner. If these patients remain comatose, dynamic flexion/extension studies with fluoroscopic guidance or a normal cervical spine MRI within 48 hours of injury is sometimes performed for cervical spine clearance, although the inherent value of either method for the exclusion of occult soft tissue injury is questionable (9,11).

Patients with neurologic deficits that are clinically attributable to a spinal cord injury deserve rapid radiographic assessment possibly including plain films, CT scanning, and MRI. In the setting of an obvious cervical spine deformity with neurologic deficits, some surgeons may immediately institute reduction measures such as cervical traction. Other surgeons may insist upon further evaluation with CT and MRI before initiating any reduction measures. The extent of radiographic workup in the setting of spinal cord injury will depend on the preferences of the individual surgeon, the unique characteristics of the fracture being evaluated, and the character of neurologic examination. Patients with incomplete spinal cord injuries, where there is some neurologic function below the level of the spinal cord injury, may warrant an emergent MRI examination to assess integrity of the spinal canal and rule out herniated discs as an explanation for the neurologic deficits. The patient with a progressive, incomplete neurologic deficit requires immediate assessment and treatment as these patients have the greatest potential to permanently lose function with treatment delay.

Thoracic and Lumbar Spine Evaluation

Awake, neurologically intact patients can have thoracic and lumbar spine precautions discontinued if they do not have any pain suggestive of spinal injury and do not have distracting injuries. Neurologically intact patients that complain of pain localizing to the spine or who harbor a distracting injury should be evaluated radiographically with a minimum of AP and lateral plain radiographs.

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Depending upon the severity of their symptoms, CT or MRI imaging may be warranted. Comatose, obtunded, or sedated/intoxicated patients should always be evaluated with plain films or CT scanning. Multisystem trauma patients often require routine CT imaging of the chest, abdomen, and pelvis. It has been suggested that limited resolution imaging of the thoracic and lumbar spine can be extracted from these data sets and used as a substitute for radiographs of these areas (12).

In patients with neurologic deficits where there is a high suspicion for spinal injury, CT scans with coronal and sagittal reconstructions are often the initial imaging modality to improve the sensitivity for diagnosis of spinal injury and also provide better anatomic details about the specific fracture. A patient with a persistent neurologic deficit and a “normal” CT scan warrants performance of an emergent MRI both to visualize the spinal cord and cauda equina and to rule out soft tissue etiologies of spinal column compromise such as herniated discs or epidural hematoma that may be not visualized with CT scanning. Some surgeons may wish to obtain emergent MRI in patients with obvious fractures diagnosed with CT, since the MRI can help locate the level of the conus medullaris, assess the integrity of the intervertebral discs, and better appreciate the extent of ligamentous injury. All of these factors may impact the treatment of the patient by providing the surgeon with a better appreciation of the anatomy of the spinal injury.

Current Treatment Options

External Orthosis

Numerous external orthosis (spinal braces) options are available for the treatment of spinal injuries. The principle of bracing is to reduce motion at the injured spinal area in order to improve the likelihood of healing and reduce the potential for neurologic injury as a result of spinal instability. In general it is felt that maximal reduction in motion will result in better healing of the injured spinal segment, but literature is lacking in regard to

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