Anatomy of the Great Posterior Radiculomedullary Artery

Abstract

BACKGROUND AND PURPOSE: Although considerable variability exists as to the overall caliber of radiculomedullary arteries, dominant radiculomedullary arteries such as the artery of Adamkiewicz exist. The existence of a great posterior radiculomedullary artery has attracted little attention and has been a matter of debate. The aim of this anatomic study was to determine the presence or absence of the great posterior radiculomedullary artery. MATERIALS AND METHODS:We performed microsurgical dissection on formaldehyde-fixed cadaveric human spinal cords. The artery of Adamkiewicz in the spinal cord specimens (n = 50) was injected with colored latex until the small-caliber arterial vessels were filled and the great posterior radiculomedullary artery was identified. The course, diameter, and location of great posterior radiculomedullary artery were documented. RESULTS:A great posterior radiculomedullary artery was identified in 36 (72%) spinal cord specimens. In 11 (22%) specimens, bilateral great posterior radiculomedullary arteries were present. In 13 cases (26%), a unilateral left-sided great posterior radiculomedullary artery was identified. In 11 cases (22%), a unilateral right-sided great posterior radiculomedullary artery was identified. In 1 specimen (2%), 3 right-sided great posterior radiculomedullary arteries were noted. The average size of the great posterior radiculomedullary arteries was 0.44 mm (range, 0.120-0.678 mm on the left and 0.260-0.635 mm on the right). CONCLUSIONS:A great posterior radiculomedullary artery is present in most (72%) individuals. The authors describe the microsurgical anatomy of the great posterior radiculomedullary artery with emphasis on its morphometric parameters as well as its implications for spinal cord blood supply. Variations of the arterial supply to the dorsal cord are of great importance due to their implications for ischemic events, endovascular procedures, and surgical approaches.

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“…Segmental perfusion of the anterior and posterior spinal arteries will be rendered, in most cases, predominantly through the artery of Adamkiewicz and the great posterior radiculomedullary artery, respectively. 8 However, the small caliber of these arteries (range, 0.5-1 mm) and their substantial anatomic variability have made their identification using preoperative imaging studies practically unattainable and, therefore, poses a challenge for their successful embolization. However, their functional importance can be reliably assessed intraoperatively using MEP monitoring, which was demonstrated in the present patient.…”

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“…The number and level of these radicular feeders are unpredictable, with a median number of four vessels and an inverse relation between the number and caliber of these vessels. 4…”

“…The number and level of these radicular feeders are unpredictable, with a median number of four vessels and an inverse relation between the number and caliber of these vessels. 4 The midthoracic region (T4-T8) has the most tenuous blood supply to the ASA, usually with up to three anterior radiculomedullary arteries contributing to the anterior longitudinal system, branches of the intercostal arteries. The diameter of the ASA is at its smallest by the end of this region, and it may even be focally discontinuous, creating a potential watershed area with conflicting downward flow from the cervical feeders and ascending flow from the lower thoracic/lumbar feeders.…”

Extremely Long Spinal Cord Infarction

“…Its rarity has been explained by abundant anastomosis between paired posterior spinal arteries (4) . Recently, however, the great posterior radiculomedullary arteries longitudinally feeding the dorsal part of the spinal cord, similar to the artery of Adamkiewicz for the ventral part, has been identified in 72% of human spinal cord specimens: one unilateral artery 48%, two bilateral arteries 22%, and three unilateral arteries 2% (5) . We speculate that the single, well-developed, great posterior radiculomedullary artery would be occluded by atherosclerosis.…”