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Spinal Cord Arteriovenous Malformations

by Michael Rubin, MDCM

Arteriovenous malformations (AVMs) in or around the spinal cord can cause cord compression, ischemia, parenchymal hemorrhage, subarachnoid hemorrhage, or a combination. Symptoms may include gradually progressive, ascending, or waxing and waning segmental neurologic deficits; radicular pain; and sudden back pain with sudden segmental neurologic deficits. Diagnosis is by MRI. Treatment is with surgery or stereotactic radiosurgery and may include angiographic embolization.

AVMs are the most common spinal vascular malformations. Most are thoracolumbar, posterior, and outside the cord (extramedullary). The rest are cervical or upper thoracic and often inside the cord (intramedullary). AVMs may be small and localized or may affect up to half the cord. They may compress or even replace normal spinal cord parenchyma, or they may rupture, causing focal or generalized hemorrhage.

Symptoms and Signs

A cutaneous angioma sometimes overlies a spinal AVM. AVMs commonly compress

  • Nerve roots, causing pain that radiates down the distribution of a nerve root (radicular pain)

  • The spinal cord, causing segmental neurologic deficits that gradually progress or that wax and wane

Combined lower and upper motor neuron deficits are common. AVMs may rupture into the spinal cord parenchyma, causing sudden, severe back pain and sudden segmental neurologic deficits. Rarely, high cervical AVMs rupture into the subarachnoid space, causing sudden and severe headache, nuchal rigidity, and impaired consciousness (see Subarachnoid Hemorrhage (SAH)).

Diagnosis

  • Imaging

Spinal cord AVMs may be detected incidentally during imaging. AVMs are suspected clinically in patients with unexplained segmental neurologic deficits or subarachnoid hemorrhage, particularly those who have sudden, severe back pain or cutaneous midline angiomas.

Diagnosis is by MRI (usually done first), then magnetic resonance angiography, and then selective arteriography. Occasionally, myelography plus CT is used.

Treatment

Surgery is indicated if spinal cord function is threatened, but expertise in specialized microtechniques is required. Stereotactic radiosurgery is helpful if the AVM is small and located in a surgically inaccessible location. Angiographic embolization occludes feeder arteries and often precedes surgical removal or stereotactic radiosurgery.

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