Variations in arterial supply to the lower lumbar spine

Several papers examined the vascular anatomy of the lumbosacral region using cadavers with angiography. However, few reports used CT angiography, and discussion on variations of fourth lumbar, fifth lumbar, and lumbar branch of iliolumbar arteries were limited. To clarify the vascular variations around the lower lumbar spine including the lumbosacral region, particularly at the posterior elements, we performed anatomical analysis using computed tomography (CT).

Extra-osseous arteries surrounding the lumbar spine including the lumbosacral region were evaluated by two orthopedic surgeons independently, using 323 consecutive abdominal contrast-enhanced multi-planner CT scans that were taken for surgical plans in colon cancer patients. Subjects were 204 men and 119 women, whose ages ranged from 15 to 89 years (mean 66.5).

Each segmental artery was visible at the L1-4 spinal levels, running from the vertebra through the lamina in 91.0 % on the right side, in 90.7 % on the left side, while it was visible in 4.6 % on the right side, in 8.7 % on the left side at the L5 level. The extra-osseous arterial supply to the L5 lamina was basically provided by two vessels on each side. One was mostly derived from the L4 segmental artery (right: 92.6 %; left: 92.0 %) that was distributed around the superior articular process, the other was derived from the iliolumbar artery (right: 62.9 %; left: 55.7 %) that was distributed around the inferior articular process through the lamina. There were mainly four combination patterns of those arteries. These combinations, which had been considered as regular patterns in textbooks, were observed in approximately 50 % (right: 55.7 %; left: 48.6 %) of patients.

Various distributions of arteries around the lower spine were identified.