Introduction Determining safer techniques for lumbar injections is an important goal in pain medicine. This study aims to characterize the location of the T10–L5 spinal arteries using CT angiogram scans to define a safer approach for sympathetic and splanchnic blocks that minimizes intra-arterial injection.

Methods CT angiograms of 68 patients were included this study. The path of the spinal arteries from the aorta origin along the vertebral body to the neural foramina was traced on axial CT images. The sagittal plane of the vertebral body was divided into nine quadrants to map the path of a spinal artery at a vertebral level. At a given vertebral level and laterality, the presence of an artery as well as the quadrants the artery traveled in along its path were recorded.

Results At the anterior vertebral body, >90% of the spinal arteries were observed either at or below the pedicle level. At the middle portion of the vertebral body from T11 to L3, >80% of the spinal arteries were found at the pedicle level. For the posterior portion of the vertebral bodies at L4 and L5, the spinal arteries terminated almost universally below the pedicle level. For other levels at the posterior vertebral bodies, the spinal arteries were equivocally located at or below the pedicle level.

Conclusion Using routine anatomic landmarks visible on CT imaging, we classified the anatomic course of low thoracic and lumbar spinal arteries originating from the aorta into the neural foraminal space. A safe recommendation to avoid intra-arterial injection for a splanchnic or lumbar sympathetic is to start above the pedicle and add a slight caudal angulation to the needle trajectory to avoid disc injury at the anterolateral vertebral body.