Most vascular disorders of the spine are due to ischemia or malformations. The posterior third of the spine is supplied by the posterior spinal arteries, while the anterior spinal artery (ASA) supplies the anterior two-thirds of the spine. The ASA receives sparse collateral circulation. The artery of Adamkiewicz, a branch off the aorta, provides circulation at the T8-L1 level through the conusmedullaris. Damage to this artery results in ASA syndrome, characterized by complete motor paralysis below the level of the lesion, loss of pain and temperature sensation at and below the lesion level, and retained proprioception and vibratory sensation. Infarcts are usually caused by aortic insufficiency, including aortic aneurysms, dissections, trauma, atherosclerosis, and surgery. ASA syndrome has poor prognosis and functional recovery. Treatment is supportive.
Vertebral body hemangiomas are the most common primary spine tumor. They are benign and rarely symptomatic, usually requiring no treatment. For those that present symptomatically, treatment options include radiation therapy, embolization, vertebroplasty, or surgery, as a last resort. Other spinal vascular disorders include spinal arteriovenous malformations (AVMs) and arteriovenousfistuals (AVFs), and, rarely, spinal cord cavernomas and venous angiomas.
Spinal Arteriovenous Malformations (AVMs)
Spinal vascular malformations comprise approximately 4% of all primary intraspinal masses. Malformations of the spine include spinal arteriovenous malformation (AVM) and spinal duralarteriovenous fistula (AVF). Spinal AVF is the most common type of spinal vascular malformation in adults and are usually located in the lumbar or lower thoracic spine. AVFs are fed by the radicular artery, forming a fistula at the dural root sleeve and draining into an engorged spinal vein on the posterior cord. Symptoms include low back pain and progressive myeloradiculopathy or caudaequina syndrome. Spinal AVMs have the same pathology as cerebral AVMs, wherein arteries drain into veins without intervening capillaries. They are rare lesions that may occur on, in, or near the spinal cord. Symptoms usually arise acutely from hemorrhage, typically progressive neurologic deficit.
Spinal AVMs may be classified into 4 types:
- type I: single coiled vessel (dural AV fistula)
- type II: intramedullary glomus AVM
- type III: juvenile
- type IV: intraduralperimedullary (AV fistula)
- sub-type I: single arterial supply (ASA), single small fistula, slow ascending perimedullary venous drainage
- sub-type II: multiple arterial supply (ASA and PSA), multiple medium fistulae, slow ascending perimedullary venous drainage
- sub-type III: multiple arterial supply (ASA and PSA), single giant fistula, large ectatic venous drainage
Individuals with both spinal AVFs and AVM should undergo angiography for pre-treatment planning. AVFs are usually amenable to endovascular techniques using glue but must be
completely occluded to prevent recurrence. Surgery is most commonly used for resection of AVMs, especially those that have hemorrhaged, intradural AVMs, and those that compress the spinal cord.
References
- Doppman JL, Di chiro G, Oldfield EH. Origin of spinal arteriovenous malformation and normal cord vasculature from a common segmental artery: angiographic and therapeutic considerations. Radiology. 1985;154 (3): 687-9