Trauma to the Spine and Spinal Cord

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60 Trauma to the Spine and Spinal Cord

Stephen R. Freidberg, Subu N. Magge

Clinical Vignette

On a winter’s morning, this vigorous hypertensive, 68-year-old musician, went to pick his newspaper off his icy driveway. He was next found lying on the ground barely able to move any extremity with the exception of some spontaneous, brief dystonic posturing of his right arm. He had no recall of what occurred. Admission to a local hospital led to a diagnosis of a brainstem stroke.

When there was no sign of improvement after 48 hours, his son-in-law, a Lahey colleague, had him transferred to our hospital. Neurologic examination demonstrated an alert, articulate gentleman with absolutely normal brainstem function, full visual fields, and normal optic fundi. He had a severe spastic quadriparesis, and bilateral Babinski signs. There was a dense spinal cord level; he had absolutely no appreciation of touch, temperature, or pin sensation below the C6 dermatomes.

Magnetic resonance imaging (MRI) of the cervical spinal cord demonstrated a large herniated midline disc compressing the spinal cord at the C5–C6. An emergency anterior cervical diskectomy and fusion adequately decompressed the spinal cord. During the subsequent 6 months, he had a slow but marvelous recovery, fully regaining almost all his neurologic function.

Comment:

This patient was most fortunate having a physician in his family who did not accept the initial diagnosis. Senior citizens are very prone to cervical spine fracture dislocation injuries particularly from such simple things as a fall in the home or on the ice as occurred here. Furthermore subsequent history led to yet another diagnosis of a cardiac arrhythmia. In retrospect it was thought that this arrhythmia led to a brief loss of consciousness, precipitating the fall that provoked his catastrophic cervical spine injury. Although acute spinal cord lesions are not often considered in the differential of a “brainstem stroke,” the demonstration of the “spinal cord level” at the time of the neurologic examination was the keystone to the diagnosis. This observation differentiated our patient’s clinical diagnosis from the initial impression of a brainstem stroke. This patient’s eventual excellent recovery was totally dependent on his consulting neurologic physician’s most careful clinical evaluation.

Traumatic spinal cord injury (TSCI) secondary to spinal column trauma is one of the most devastating human injuries in terms of morbidity, changes in the normal activities of daily living, and severe economic costs to the patient, family, and society. The recognition of the seriousness of spinal cord injury dates back to antiquity. It was noted in the Edwin Smith Surgical Papyrus dating to the 17th century BC. The recent major interest in stem cell research has brought hope to many TSCI individuals; however, no matter how promising one might think these techniques may prove to be, it is likely that successful clinical application of these technologies are many years removed. These patients and their physicians need to be realistic and take heart in the plethora of current research into rehabilitation problems and the opportunity to adequately confront the long-term medical, social, psychological, urological, and skin issues that they are faced with going forward. Unfortunately, war settings such as have recently occurred in Iraq and Afghanistan always lead to a major influx of TSCI patients.

When one reflects on the greatly shortened life spans that TSCI individuals faced 50 years ago, today’s survivors are a marvel to both their own courage as well as many medical advances. In spite of the neurologic injury, most TSCI patients are able to live active, productive lives. The Americans with Disabilities Act of 1990 has removed many physical barriers to wheelchair accessibility and has prevented discrimination in the workplace. To watch the wheelchair paraplegics come to the finish line of the Boston marathon speaks to these triumphs.

Major trauma centers evaluate two to three TSCI individuals out of every 100 patients brought to their emergency departments. The very high mortality (50%) associated with TSCI occurs mainly at the initial accident scene. Most often, these patients are accidentally injured while in an automobile (Fig. 60-1) or on a motorbike, particularly motorcycles. This type of injury also predisposes the patient to multiple-organ damage, for example, brain shear injury and/or intracerebral or subdural/epidural hematoma, cardiac tamponade, or a ruptured aorta, often leading to their very substantial fatality rate. In contrast, nonvehicular spinal cord injuries often occur with falls in (Fig. 60-2) or near the home (Fig. 60-3).

Figure 60-1 Cervical Spine Injury: Compression.

Figure 60-2 Cervical Spine Injury: Hyperextension.

Figure 60-3 Cervical Spine Injury: Hyperextension Flexion-Rotation.

These patients have a 16% mortality rate if they survive to get to the hospital. Young men sustain 85% of TSCI, and thus there is a high correlation with alcohol, motor vehicle accidents, or athletic injuries usually from contact sports or on occasion skiing, diving, or trampolines. In the older population, individuals having significant predisposing cervical spinal spondylosis and/or stenosis are much more likely to develop TSCIs, a central cord injury (Fig. 60-2), from relatively simple falls on stairs or precipitously while navigating icy walkways.

The dollar cost per year is estimated at $4 billion to care for the acute and long-term needs of the patient with TSCI. The costs to the patient and family are incalculable as their problems will last a lifetime. The patient with a spinal cord injury must adjust to limited mobility, psychiatric issues, urological problems, pulmonary difficulty, skin breakdown, sexual dysfunction, and frequently the inability to perform his or her job. The higher within the spinal cord the level of neurologic injury, the more difficult will be the patient’s adjustment to the injury. Clearly, TSCI is a condition where the opportunity for prevention far exceeds the potential for treatment. The patient in the opening vignette of this chapter was extremely fortunate and is not an example of the typical course of TSCI. The American Association of Neurological Surgeons sponsors an effective and aggressive program, Think First. This program has brought the very meaningful message of prevention to more than 8 million high school and elementary school pupils in almost all of the United States and seven foreign countries.

Pathophysiology

Different types of trauma can lend themselves to severe spinal cord injury. One of the most well-known, particularly among adolescents, is that related to diving or vehicular trauma leading to compression damage to the spine and concomitantly the spinal cord (see Fig. 60-1). The more senior population is primarily subject to TSCI in relation to seemingly simple falls in the home (see Fig. 60-2); similarly, alcoholics or abusers of other drugs are also at significantly increased risk of spinal cord trauma (see Fig. 60-3).

In addition to the various types of trauma to the vertebrae per se (Fig. 60-4), there may be gross external cord trauma varying from a simple contusion to a total severing of the proximal from the distal cord, and there is often very significant intramedullary microvascular thrombosis. This is associated with hemorrhage and necrosis secondary to infarction. The hemorrhage is probably venous in origin. Toxic excitatory amines produced by the trauma worsen the secondary injury.

Figure 60-4 Fracture and Dislocation of Cervical Vertebrae.

Initial Management

Many spinal cord injuries, particularly of vehicular or wartime origin, have a number of other important associated clinical accompaniments equally demanding immediate focus and intervention. Thus, usually it is not possible to focus on the problems of spine and spinal cord trauma per se as isolated clinical phenomena in such settings. Frequently multisystem injuries are concomitantly present, leading to issues such as hypotension, hypoxia, infection, and the need for surgery on other organ systems. Each and every one of these factors complicates the treatment of the spine injury. The ABCs of Advanced Trauma Life Support, that is, Airway, Breathing, and Circulation, demand immediate medical attention. Because any degree of hypotension and hypoxia will further the intrinsic spinal cord injury, it is absolutely essential that everything be done to minimize any subsequent injury to the contused spinal cord secondary to inadequate blood supply and/or oxygen (Fig. 60-5).

Figure 60-5 Suspected Cervical Spine Injury: Treatment at Site of Accident.

Diagnostic Approach

Cervical Spine

Most trauma patients require spinal computed tomographic (CT) examination especially with the alert patient who complains of neck pain, and/or tenderness even when he or she has no obvious neurologic deficits. While the neck is still immobilized, if modern CT scanning is available, spinal CT is indicated. This examination is very rapid and is so elegant that it is our procedure of choice (see Fig. 60-1 and 60-2). It is definitely more useful than plain radiographs as it offers the opportunity to provide reconstruction of the CT data in sagittal, coronal, or any angled plane desirable to the physician. The elegance of modern CT scanning far surpasses the utilization of plane spine radiographs performed with portable technique in the emergency department. However, in settings lacking the rapid CT scan capabilities, standard radiographic imaging still provides very important initial screening for fracture dislocations. This three-view cervical spine study must include lateral, anteroposterior, and open-mouth views of the odontoid. It is essential to visualize the entire cervical spine from the occiput through T1. Whenever this traditional imaging is questionable or just inadequate, thin-cut CT scanning with reconstruction through the questionable areas must be performed. In addition, when caring for any head trauma patient requiring CT, the scanning must always be carried through the cervical spine.

Whenever there is any neurologic injury, an MRI (see Fig. 60-2) is performed before removing the collar or instituting therapy. An MRI will elegantly provide evidence of any spinal cord injury, nerve root pressure, disc herniation, and ligamentous soft tissue injury. A normal examination makes it safe to remove the collar support and allow for early mobilization. This mitigates the possibility of skin breakdown if the patient unnecessarily remains in a hard cervical collar for prolonged periods of time. Formal MRI imaging may not be necessary if the trauma victim is alert, has no neck pain or tenderness, full painless range of motion of the neck, a normal neurologic examination, and no evidence of alcohol or illicit drug use,.

In the circumstance of the neurologically intact patient with definite posttraumatic neck pain, but whose cervical radiographs and/or CT are normal, it is still essential to evaluate for the possibility of a subtle but unstable fracture dislocation with potential for severe cord injury. Here one must obtain dynamic, lateral flexion/extension radiographs or fluoroscopy. These required neck excursions can be performed by the cooperative patient. However, in the setting when the patients are not cooperative or are obtunded, these individuals must be kept in rigid collar until flexion–extension films can be performed passively by a neurosurgeon, orthopaedic spine surgeon, neuroradiologist, or other experienced trauma physician.

Thoracic, Thoracolumbar, and Lumbar Spine

For injuries to the thoracic, thoracolumbar, and lumbar spines, plain radiograph, CT, and MRI scanning are all used. MRI is a mandatory examination whenever there is any question of injury to the spinal cord or disc rupture. Plain bony radiographs may point to and demonstrate any specific vertebral injuries. However, to see the extent of the fracture and/or any spinal canal compromise by bone, CT scanning reconstruction is the study of choice.

Treatment

Immediate

Treatment begins at the accident scene. EMT personnel are trained to safely extract injured patients from the accident location. This may include individuals within or those thrown from a motor vehicle, the presence of a football helmet, or an elderly person who has just taken a fall and is found in an awkward position in the bathroom. Immediate spine immobilization is mandatory; the patient is placed on a back board with his or her neck in a collar, taped to the board with the spine stabilized to prevent secondary injury (see Fig. 60-5). This position must be maintained until the entire spine is clinically, and usually radiologically, cleared by appropriate physicians. Because of spinal instability, 4% of patients with TSCI deteriorate after initial attempts at treatment. Nonoperative spinal stabilizing techniques include a collar, craniocervical traction, a halo, a rotating frame, or rocking bed (Fig. 60-6).

Figure 60-6 Cervical Spine Injury: Traction and Bracing.

Corticosteroids

Therapeutic guidelines published in 2002, vis-à-vis immediate medical treatment of spinal cord injury, established a consensus that there is insufficient evidence to support initiating corticosteroid treatment as a standard despite the then traditional and widespread use of this medication. This controverts a 1990 document sponsored by the National Acute Spinal Cord Injury Study. Corticosteroids are sometimes mentioned currently as a TSCI treatment option “that should be undertaken only with the knowledge that the evidence suggesting harmful side effects is more consistent than any suggestion of clinical benefit.” In fact, the Canadian Neurosurgical Society states that steroids are contraindicated for spinal cord trauma.

Surgery

When spinal cord neural compression is documented or bony spine misalignment is evident, neurosurgical and/or orthopedic surgery intervention must be immediately considered. The degree of neural compression is assessed by CT and MRI. Significant spinal cord or nerve root compression requires surgical decompression and stabilization. The issue of stability can be difficult to evaluate. There is disagreement among neurosurgeons regarding the timing of surgery. Earlier surgical decompression and stabilization are championed by some when there is a partial lesion, especially with residual autonomic function, as this greatly improves the potential for neurologic improvement.

In contrast, the outlook for improvement with a complete spinal cord lesion is very poor. However, some neurosurgeons feel that early surgery and stabilization, even with complete lesions, allows for early mobilization and rehabilitation, possibly reducing the significant morbidity of prolonged bedrest. Early surgery may also be indicated for facet fractures to improve nerve root function. Other neurosurgeons are more conservative and wait until the patient’s neurologic recovery has plateaued before any surgery. It is generally thought that regardless of the timing, surgical decompression and fusion provides better neurologic results than nonoperative treatment even after a long delay. This applies to both spinal cord and/or nerve root injury.

Controversy continues to exist as to whether early surgery with complete cord injury improves neurologic function compared to late surgery. In summary, the goals of surgery are twofold: to decompress the neural elements and to stabilize the spine. This allows the best chance for early mobilization. There are also specific evaluation and therapeutic approaches necessary depending on the anatomical site of injury.

Atlanto-axial (C1–2)

In the cervical spine, open-mouth odontoid films are used to demonstrate the relationship of the lateral masses of C1 with the articular pillars of C2. The “rule of Spence” states that if the sum of the overhang of both C1 lateral masses on C2 is greater than 7 mm, then the transverse ligament is likely disrupted, resulting in C1–2 instability. Treatment typically involves halo vest immobilization or occipitocervical fusion (see Fig. 60-4).

Dens fractures are subclassified (see Fig. 60-4). Type 1 fractures occur through the tip of the dens above the transverse ligament. They are quite rare and may be associated with atlantoaxial instability, necessitating arthrodesis. Type 2 fractures, the most common, occur through the base of the dens and are usually unstable (Figs. 60-4 and 60-6).

There is considerable controversy regarding treatment. The primary indications for surgery include a displacement of the dens greater than 6 mm, instability in a halo, and painful non-union. Otherwise, this treatment consists of immobilization in a halo or hard cervical collar. Type 3 fractures occur through the body of C2 and are usually stable, healing with immobilization in a hard collar or halo vest (see Fig. 60-6).

Traumatic spondylolisthesis of the axis caused by bilateral fractures of the C2 pars interarticularis is known as “hangman’s fracture.” Judicial hangings (executions) caused injury by hyperextension and distraction (Fig. 60-8). Today these injuries are caused by hyperextension and axial loading.

Figure 60-8 Plain Radiograph of Hangman’s Fracture: Cervical Spine.

Type 1 hangman’s fractures have minimal angulation and less than 3-mm subluxation. These are considered stable. Treatment involves fracture reduction and stabilization in a hard collar or halo. Type 2 hangman’s fractures have 4 mm or more subluxation. These are usually unstable and require reduction and stabilization in halo. Type 3 hangman’s fractures involve marked disruption of C2–3 posterior elements and wide subluxation. These injuries are often fatal. They require open reduction and stabilization via C2–3 anterior discectomy and fusion or posterior C1–3 fusion.

Figure 60-7 Dens Fracture of Cervical Spine.

Subaxial Cervical Spine

Subluxation is defined by neutral spinal radiographs demonstrating instability with greater than 3.5 mm or angulation greater than 11 degrees. Injuries resulting in stable fractures usually heal well with immobilization in hard collar or halo. Grossly unstable injuries require surgical stabilization (see Fig. 60-8, Fig. 60-9).

Figure 60-9 Non-Axial Burst Fracture: Cervical Spine.

Thoracolumbar Spine

Approximately 64% of spine fractures occur at the thoracolumbar junction (Fig. 60-10). These can be successfully repaired; however, the degree of initial, spinal cord or cauda equina injury usually determines the long-term prognosis.

Figure 60-10 Burst Fracture: Lumbar Spine.

Prognosis

Spinal cord injury remains an absolutely devastating life-altering injury. When there is complete loss of neurologic function, clinical improvements allowing return to some activities of daily living are totally dependent on the availability of superior physiatric rehabilitation medical principles rather than anatomic spinal cord regeneration. Obviously whenever there is a complete spinal cord transection, there is no possibility for any specific return of clinical neurologic function. However, the presence of a partial lesion, with even residual autonomic function, provides some potential for a degree of certain neurologic functions.

Early patient mobilization is mandatory; it is a primary treatment goal. Deconditioning and morbidity are associated with any significant bedrest. This also makes the patient more susceptible to major complications, particularly deep venous thrombosis (DVT) and/or phlebitis, pneumonia, and skin breakdown. Interestingly the incidence of DVT appears to be relatively low (2–3%) and not influenced by use of heparin.

Fortunately, patients with TSCI now have many entrees back into a normal life. Many hold full-time jobs, including being teachers, physicians, or attorneys (Fig. 60-11). They can marry and have children as better understanding of sexual function in the spinal injury patient has led to excellent counseling and means to perform adequately in this setting. Lastly many athletic endeavors are now available as best exemplified by the many wheelchair participants in the marathon (see Fig. 60-11).