A spinal stroke (Spinal Cord Infarction) is a serious medical event caused by a sudden interruption of blood flow to the spinal cord. This lack of oxygen and nutrients (ischemia) rapidly leads to tissue damage and neurological dysfunction. Spinal cord infarction is notably rare, accounting for less than one percent of all stroke cases. Prompt recognition and treatment are necessary due to the potentially severe outcome.
The Underlying Mechanism of Spinal Cord Infarction
The spinal cord depends on a network of blood vessels for a continuous supply of oxygenated blood. The primary vascular supply consists of a single anterior spinal artery (ASA) and two posterior spinal arteries (PSA). These arteries run vertically along the cord and are fed by smaller radicular arteries branching off the aorta.
The ASA is functionally dominant, supplying the anterior two-thirds of the spinal cord, including the motor tracts and pathways for pain and temperature sensation. Blockage in the ASA territory is the most frequent type of spinal stroke, causing extensive tissue damage in these areas. The PSA supply the dorsal columns, which transmit information about vibration and position sense.
Infarction occurs when a blockage, such as a blood clot or an embolus, obstructs the flow in a feeder artery or the ASA itself. Because collateral circulation in the spinal cord can be sparse, especially in the mid-thoracic region, this interruption quickly starves the tissue of oxygen. This localized tissue death causes the abrupt and profound neurological deficits associated with the condition.
Immediate Symptoms and Clinical Presentation
The hallmark of a spinal stroke is the acute, sudden onset of symptoms, typically reaching maximum severity within minutes to a few hours. The presentation often begins with a sudden, severe, and sharp pain located in the neck or back, usually at the level of the vascular occlusion. This pain is frequently followed immediately by the rapid development of motor weakness.
Patients commonly experience rapidly progressing bilateral weakness, manifesting as paraplegia (paralysis of the lower body) or tetraplegia (paralysis of all four limbs), depending on the infarction location. This motor dysfunction is accompanied by sensory loss below the affected spinal level. Pain and temperature sensations are typically lost bilaterally due to the involvement of the anterior cord.
A distinguishing feature is the preservation of vibration and position sense, as the posterior columns are supplied by the posterior spinal arteries and are often spared. Autonomic functions are also frequently compromised, leading to immediate bladder and bowel dysfunction, such as urinary retention.
Identifying the Root Causes and Risk Factors
Spinal strokes are often triggered by events that compromise blood flow in the major arteries supplying the spinal cord. One frequently identified cause is a complication from aortic surgery, particularly procedures involving the thoracic or thoracoabdominal aorta. Temporarily clamping the aorta during these operations disrupts blood flow from the feeder arteries, leading to ischemia.
Other significant causes include aortic dissection, where a tear in the aorta impedes blood delivery, and severe systemic hypotension (low blood pressure). Hypotension often occurs during critical illness or major surgery and can be insufficient to perfuse the spinal cord. Less common causes involve the blockage of small spinal arteries by material originating elsewhere, such as fibrocartilaginous emboli.
Underlying conditions amplify the risk. Risk factors like severe atherosclerosis, uncontrolled high blood pressure, and diabetes contribute to the narrowing and hardening of arteries. These conditions make the spinal cord’s blood supply more vulnerable to sudden interruption, even from a modest drop in blood pressure.
Diagnosis and the Recovery Pathway
A suspected spinal stroke requires immediate medical evaluation, as symptoms can mimic other conditions like acute transverse myelitis or spinal cord compression. Magnetic Resonance Imaging (MRI) is the preferred diagnostic tool, used to visualize the ischemic area and exclude compressive lesions. Although an MRI may not show definitive signs of infarction immediately, ruling out other causes guides acute management.
Acute treatment focuses on supportive measures, as there is no specific clot-busting drug approved for spinal stroke. Medical teams stabilize the patient, maintain adequate blood pressure to maximize spinal cord perfusion, and manage symptoms like pain and bladder dysfunction. Addressing the underlying cause, such as repairing an aortic tear or correcting severe hypotension, is a simultaneous priority.
The long-term outlook and recovery are highly variable, depending on the initial severity and location of the damage. Recovery involves extensive inpatient and outpatient physical and occupational therapy to maximize functional return. The extent of permanent neurological deficit is determined by the amount of tissue irreversibly damaged by the initial lack of blood flow.