Spinal cord compression overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Spinal cord compression develops when the spinal cord is compressed by bone fragments from a vertebral fracture, a tumor, abscess, ruptured intervertebral disc or other lesion. It is regarded as a medical emergency independent of its cause, and requires prompt diagnosis and treatment to prevent long-term disability due to irreversible spinal cord injury.
Pathophysiology
The spinal cord extends from the foramen magnum down to the level of the first and second lumbar vertebrae. The cord is protected by the vertebral column, which is mobile and allows for movement of the spine. It is enclosed by the dura mater and the vessels supplying it. The spinal cord and nerve roots depend on a constant blood supply to perform axonal signaling. Conditions that interfere, either directly or indirectly, with the blood supply will cause malfunction of the transmission pathway. Injury to the spinal cord or nerve roots arises from direct trauma, compression by bone fragments, hematoma, or disk material or ischemia. The tissue responses by gliosis, demyelination, and axonal loss. This results in injury to the white matter (myelinated tracts) and the gray matter (cell bodies) in the cord with loss of sensory reflexes (pinprick, joint position sense, vibration, hot/cold, pressure) and motor function.
Natural History, Complications and Prognosis
Once complete paralysis has been present for more than about 24 hours before treatment, the chances of useful recovery are greatly diminished, although slow recovery, sometimes months after radiotherapy, is well recognised. The median survival of patients with metastatic spinal cord compression is about 12 weeks, reflecting the generally advanced nature of the underlying malignant disease.
Diagnosis
History and Symptoms
Symptoms suggestive of cord compression are back pain, a dermatome of increased sensation, paralysis of limbs below the level of compression, decreased sensation below the level of compression, urinary and fecal incontinence and/or urinary retention.
X Ray
Diagnosis is by x rays but preferably magnetic resonance imaging (MRI) of the whole spine.
MRI
Diagnosis is by x rays but preferably magnetic resonance imaging (MRI) of the whole spine. The most common causes of cord compression are tumors, but abscesses and granulomas (e.g. in tuberculosis) are equally capable if producing the syndrome. Tumors that commonly cause cord compression are lung cancer (non-small cell type), breast cancer, prostate cancer, renal cell carcinoma, thyroid cancer, lymphoma and multiple myeloma.
Treatment
Medical Therapy
Dexamethasone (a potent glucocorticoid) in doses of 16 mg/day may reduce edema around the lesion and protect the cord from injury. It may be given orally or intravenously for this indication.
Surgery
Surgery is indicated in localised compression as long as there is some hope of regaining function. It is also occasionally indicated in patients with little hope of regaining function but with uncontrolled pain. Emergency radiation therapy (usually 20 Gray in 5 fractions) is the mainstay of treatment for malignant spinal cord compression. It is very effective as pain control and local disease control. Some tumors are highly sensitive to chemotherapy (e.g. lymphomas, small cell lung cancer) and may be treated with chemotherapy alone.