A spinal epidural hematoma (SEH) is a collection of blood forming within the spinal canal, specifically in the space between the dura mater (the outer membrane of the spinal cord) and the surrounding vertebrae. This accumulation creates a mass that exerts pressure on the spinal cord or the nerve roots extending from it. Although relatively rare, with an estimated annual incidence of about 0.1 to 1 per 100,000 people, SEH represents a serious medical issue. Because the spinal canal is a confined space, even a small amount of bleeding can quickly lead to compression, resulting in rapid neurological decline and potentially permanent paralysis if not addressed swiftly.
What Is a Spinal Epidural Hematoma and Why Does It Occur
The spinal canal encases the spinal cord. The epidural space is the area situated just outside the dura mater, containing fat, connective tissue, and a network of blood vessels known as the Batson vertebral venous plexus. SEH develops when one of these vessels, most commonly a vein from the venous plexus, tears and bleeds into this space. The resulting blood clot expands, mechanically squeezing the spinal cord and disrupting its function.
Spinal epidural hematomas arise from several distinct causes. Trauma is a recognized factor, even minor trauma in susceptible individuals. Bleeding disorders (coagulopathies) or the use of anticoagulant medications significantly increase the risk of developing SEH. These factors impair the body’s ability to stop bleeding, allowing a hematoma to form and expand.
Medical procedures involving the spine are another cause of SEH, referred to as iatrogenic causes. Procedures like lumbar punctures, spinal surgery, or the placement of epidural anesthesia needles carry a small risk of causing bleeding. In many instances, however, SEH is classified as “spontaneous,” meaning it occurs without any apparent preceding trauma or medical procedure. Risk factors like vascular malformations or high blood pressure are sometimes identified, but up to 40 to 50% of spontaneous cases lack a definitive cause.
Recognizing the Acute Symptoms
The clinical presentation of SEH is typically abrupt and involves rapidly worsening symptoms. The initial and most common symptom is the sudden onset of severe, localized back pain. This pain is often described as sharp and may be disproportionate to any preceding activity or injury. Depending on the location of the bleeding, the pain may also radiate into the limbs, following the path of the compressed nerve roots (radicular pain).
As the hematoma expands and compresses the spinal cord, neurological symptoms emerge and progress quickly. Patients may experience weakness or numbness in the legs (paraparesis), or abnormal sensations like tingling (paresthesia). The progression of motor and sensory deficits can be swift, often developing over minutes to hours.
A particularly concerning sign of spinal cord compression is the loss of control over bladder or bowel function, such as urinary retention or incontinence. Because the window for a successful outcome is narrow, the rapid progression of back pain followed by any new or worsening neurological deficit demands immediate emergency medical evaluation.
Diagnosis and the Urgency of Intervention
When SEH is suspected, a physical examination focuses on a detailed neurological assessment to determine the extent and level of spinal cord or nerve root dysfunction. This examination checks for motor strength, sensation, and reflexes to help localize the affected area. Tenderness upon palpation over the site of the hematoma is another common finding during the initial assessment.
The definitive diagnostic tool for visualizing the hematoma and determining the degree of spinal cord compression is Magnetic Resonance Imaging (MRI). MRI provides superior soft tissue detail, clearly showing the collection of blood in the epidural space and its effect on the spinal cord. If MRI is not immediately accessible, a Computed Tomography (CT) scan may be performed as an alternative, but it offers less detail regarding the soft tissues of the cord.
The time interval between the onset of severe symptoms and surgical decompression is a significant factor in predicting recovery. Neurological function loss can become permanent if the pressure on the spinal cord is not relieved within a short timeframe, often cited as 6 to 12 hours of the onset of severe deficits. Delays in diagnosis or intervention can lead to irreversible neurological injury, underscoring the necessity for immediate neurosurgical consultation upon suspicion of SEH.
Treatment Options and Recovery
For a symptomatic SEH causing progressive neurological deficits, emergency surgical decompression is the standard course of action. This procedure usually involves a laminectomy, where a section of the vertebral bone is removed to gain access to the spinal canal. The surgeon then evacuates the blood clot, immediately relieving the compressive pressure on the spinal cord and nerve roots.
In cases where the hematoma is small, non-progressive, and the patient has minimal or no neurological symptoms, conservative management may be considered. This approach involves close observation and supportive measures, such as pain control and reversing any underlying blood-thinning issues. However, this non-operative management is the exception and requires ongoing monitoring for neurological deterioration.
The prognosis for recovery is closely linked to the patient’s neurological status before surgery and the speed of decompression. Patients who have minor deficits or who undergo surgery sooner (ideally within 12 to 36 hours of symptom onset) generally exhibit better neurological recovery. Following the acute phase, physical rehabilitation is often necessary to help patients regain lost motor function and adapt to any residual deficits.