A. Introduction. Spinal cord compression is a medical emergency that requires prompt intervention. The clinical diagnosis of cord compression may be difficult because early symptoms are often attributed to more common processes. Furthermore, the characteristic symptoms often occur too late to prevent irreversible damage. Clinical suspicion is therefore paramount, and early diagnosis is key to good outcomes.
B. Causes of Spinal Cord Compression
a. Malignancy, most often from metastatic disease, is the most common cause of spinal cord compression. Consistent with the number of each type of vertebrae, the thoracic vertebrae are most often involved, followed by approximately equal involvement of the cervical and lumbosacral vertebrae.
i. If you remember the cancers that involve the bone—breast, lung, thyroid, kidney, prostate, and multiple myeloma—you will remember the most common causes of spinal cord compression (see Chapter 73). Breast, lung, and prostate cancer account for most cases of cord compression.
ii. Lymphomas, primary spinal tumors (i.e., meningiomas, neurofibromas), and many other malignancies can also cause spinal cord compression.
b. Infections. Epidural abscesses, diskitis, and osteomyelitis (e.g., from bacteria or tuberculosis) can lead to cord compression.
c. Herniated disks that are large and central in location occasionally result in cord compression.
d. Epidural hemorrhage may occur spontaneously or result from arteriovenous malformations, trauma, anticoagulation therapy, or underlying tumors, resulting in cord compression.
e. Rheumatologic disorders. Arthritis (especially rheumatoid arthritis) with cervical involvement can result in cord compression from relatively minor trauma (e.g., whiplash, intubation). Ankylosing spondylitis may result in lumbar cord compression.
f. Trauma. Motor vehicle collisions, falls, and assault can cause spine fracture and cord compression. Injuries causing concussion (e.g., loss of consciousness) are frequently accompanied by spine injury.
C. Clinical Manifestations of Spinal Cord Compression
a. Back pain is the most common symptom and is present in at least 80% of patients. The quality of the pain is variable and nonspecific and does not usually allow spinal cord compression to be distinguished from more benign disorders. Point tenderness over the involved vertebrae is common in spinal cord compression and should raise a red flag.
i. If the lesion is in the cervical or thoracic spine, upper motor neuron weakness will be seen (e.g., increased tone, hyperreflexia, and extensor > flexor weakness in the arms and flexor > extensor weakness in the legs). There may also be a sensory level, dissociated sensory signs (e.g., preserved pain/temperature but diminished vibration/joint position sense), constipation, and urge incontinence.
ii. If the lesion affects the lumbar spine and thus the cauda equina, lower motor neuron weakness will be seen (i.e., decreased tone, hyporeflexia, and weakness in the pattern of the nerve roots affected). Saddle anesthesia, numbness in the distribution of a nerve root, constipation, and urinary retention with overflow incontinence are seen if the sacral plexus/perineal nerve roots are also involved.
iii. Lesions in the conus medullaris (located at the level of vertebrae L1–2) can cause both upper and lower motor neuron weakness and often affects bladder function.
Upper motor neuron signs do not always develop immediately in patients with acute spinal cord compression. Do not rule out the possibility of acute cord compression solely because upper motor neuron signs are absent.
D. Approach to the Patient. Diagnosis depends on imaging studies. If you suspect cord compression, always obtain an imaging study to rule this in or out as soon as possible.
i. Magnetic resonance imaging (MRI) is extremely sensitive and noninvasive and is therefore the preferred imaging modality. The entire cord should ideally be evaluated because multiple skip lesions are sometimes present. Focused imaging—in the setting of a focal deficit—may be appropriate.
ii. Computed tomography (CT) with a myelogram can be used when MRI is not available or is contraindicated.
iii. Radiographs and bone scans are of little value in the diagnosis of cord compression (although they may be a useful initial screen in patients presenting only with back pain). Radiographs are not sensitive enough to detect vertebral metastases, and neither test evaluates the spinal cord or nerve root itself.
i. Absolute indications. The following patients usually require testing:
1. All patients with a known cancer accompanied by symptoms or signs of possible cord compression (e.g., severe back pain)
2. Patients with focal neurologic symptoms or signs (e.g., gait difficulty, bowel or bladder incontinence, saddle anesthesia, bilateral weakness or numbness)
ii. Risk stratification. In the remaining patients who present with back pain, you can perform a simple risk stratification to assess the likelihood of possible cord compression and the appropriateness of imaging studies.
1. Simple back pain. Patients with back pain who are younger than 50 years, without a history of cancer or weight loss, and with normal neurologic examinations have musculoskeletal pain approximately 99% of the time. Usually, no tests are indicated, and conservative therapy is appropriate.
2. Back pain with risk factors. Risk factors include pain that is worse at rest, history of or suspected malignancy, history of chronic infection (e.g., tuberculosis), history of recent trauma, age older than 50 years, pain lasting for more than 1 month, history of intravenous drug use, steroid use, unexplained fever or weight loss, and spine percussion tenderness. Patients with these risk factors have a higher incidence of an underlying malignancy or infectious process. They are often initially evaluated with plain radiographs, complete blood count (CBC), and an erythrocyte sedimentation rate (ESR). If these test results are abnormal or if conservative therapy has failed to resolve the back pain, additional diagnostic tests and imaging to rule out serious causes of back pain are indicated.
If spinal cord compression is suspected, then imaging studies should be performed immediately. Patients with stable symptoms may be evaluated on a less acute basis. However, change in stable symptoms also warrants rapid imaging. MRI is the imaging modality of choice for spinal pathologies.
i. Steroids. High-dose dexamethasone (often 10–100 mg given by intravenous [IV] route) followed by 4–24 mg every 6 hours (IV or orally) is often administered.
If cord compression is suspected, do not wait for the MRI results before initiating treatment. There is usually little harm in one dose of steroids if your clinical diagnosis proves incorrect.
ii. Radiation therapy should be initiated if the diagnosis of metastatic cord compression is made. The combination of steroid treatment plus radiation therapy is more beneficial than radiation alone presumably because steroids decrease the swelling associated with radiation.
iii. Ketoconazole administered IV can reduce malignant prostatic metastases acutely; therefore, it is sometimes used in patients who have known prostate cancer associated with cord compression.
iv. Chemotherapy alone is sometimes effective in patients with extremely chemosensitive tumors (e.g., small cell lung cancer, lymphoma).
v. Emergency surgery. Early consultation with a neurosurgeon is essentiall and can prevent long-term disability. Surgery for cord compression is usually indicated in the setting of:
1. Rapidly progressive or fluctuating neurologic deficits
2. Radiation therapy failure or spinal instability
3. Radioinsensitive tumors
4. Unclear etiology of cord compression (i.e., for diagnostic and therapeutic purposes)
b. Infection. Whenever possible, a microbiologic diagnosis should be made. Treatment with antibiotics is tailored to the pathogen. Surgery may be indicated if the spine is unstable.
c. Herniated disk. Surgery is usually indicated if there is a myelopathy (e.g., spinal cord involvement), progressive motor deficit, bowel or bladder incontinence, or radicular pain unrelieved by conservative therapy for 5 months.
d. Traumatic spinal cord injury
i. Hemodynamic support. Maintenance of perfusion is critical in traumatic spinal cord injury. Thus, hypotension and hypoxemia should be prevented.
ii. Steroids. High-dose intravenous methylprednisolone is an option if the patient presents within 8 hours of the injury (30 mg/kg over 1 hour then 5.4 mg/kg/hr for 24 hours if started within 3 hours of injury and for 48 hours if started within 8 hours of injury).
iii. Surgery may be indicated if there is an unstable spine fracture and neurosurgical consultation is always indicated.
Suggested Further Readings
Al-Qurainy R, Collis E. Metastatic spinal cord compression: diagnosis and management. BMJ 2016;353.Find this resource:
Deyo RA, Weinstein JN. Low back pain. N Engl J Med 2001;344:363–70. (Classic Article.)Find this resource:
Ropper AE, Ropper AH. Acute spinal cord compression. N Engl J Med 2017;376:1358–69.Find this resource: