From the Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA.
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Dr. Hornicek or an immediate family member has received research or institutional support from Stryker; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research–related funding (such as paid travel) from Biomet; and serves as a board member, owner, officer, or committee member of the American Association of Tissue Banks and the International Society of Limb Salvage. Dr. Schwab or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Synthes and Stryker Spine; serves as a paid consultant to and serves as a board member, owner, officer, or committee member of Biom’up; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non-research–related funding (such as paid travel) from Globus Medical and Stryker. Neither Dr. Colman nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article.
Received June 08, 2014
Accepted January 03, 2015
Journal of the American Academy of Orthopaedic Surgeons: October 2015 – Volume 23 – Issue 10 – p 581-591
The blood supply to the spine is based on a predictable segmental vascular structure at each spinal level, but true radiculomedullary arteries, which feed the dominant cord supply vessel, the anterior spinal artery, are relatively few and their locations variable. Under pathologic conditions, such as aortic stent grafting, spinal deformity surgery, or spinal tumor resection, sacrifice of a dominant radiculomedullary vessel may or may not lead to spinal cord ischemia, depending on dynamic autoregulatory or collateral mechanisms to compensate for its loss. Elucidation of the exact mechanisms for this compensation requires further study but will be aided by preoperative, intraoperative, and postoperative comparative angiography. Protocols in place at our center and others minimize the risk of spinal cord ischemia during planned radiculomedullary vessel sacrifice.
General Structure of Spinal Cord Blood Supply
The spinal cord is nourished by a structure of arterial supply that follows a generally predictable path from the great vessels to the parenchyma of the white and gray matter throughout the spinal cord (Figure 1). Segmental vessels originate from the great vessels of the neck, thorax, and abdomen at each segmental level and, with few exceptions, are paired bilaterally. Although the segmental vessel typically divides into an anterior and posterior ramus, the posterior ramus is the dominant vessel and divides further into a muscular branch and a spinal branch. The spinal branch becomes an anterior radicular artery and a posterior radicular artery as it traverses the neuroforamen alongside the segmental nerve root. There are 31 paired radicular arteries, one for each segmental level, but relatively few of them contribute meaningfully to the spinal cord. Most end within the nerve root, dura, or pial plexus.
Illustration of typical spinal cord blood supply under normal conditions. One radiculomedullary vessel is shown, which supplies the anterior spinal artery through a hairpin loop.