ABSTRACT
<p><b>BACKGROUND</b>Several studies, including those done in China, report that paravertebral vascular injury during posterior spinal surgery can greatly harm patients, though it is a relatively rare complication. However, few studies have examined their course and anatomic relationship to the spine. The aim of this study was to measure the course of the major paravertebral vessels and their positional relationships to the vertebral bodies in Chinese subjects using computed tomography.</p><p><b>METHODS</b>We studied a total of fifty subjects who underwent thoracolumbar computed tomography from T1-S1 at our institution. We measured the theoretical distance, actual distance, theoretical angle, and actual angle of the paravertebral vessels at each thoracolumbar intervertebral disc.</p><p><b>RESULTS</b>The paravertebral artery actual angle at T4-L4 ranged from -11.41 to 79.75° and the actual distance from 16.98 to 52.53 mm. The actual angle of the inferior vena cava at L1-L5 intervertebral disc ranged from -40.75 to 34.50° and the actual distance from -36.63 to 61.69 mm. There was no significant difference in the actual angle of the paravertebral vein or in the actual distance in the thoracic segments according to gender (P > 0.05). However, the actual distance in the lumbar segments were significantly different according to gender (P < 0.05).</p><p><b>CONCLUSIONS</b>The major paravertebral vessels' course is closer to the mid-sagittal plane as they move posterior along the vertebrae, and the actual distance of the paravertebral artery and azygos vein increase, while the actual distance of the inferior vena cava decreases. The course of the lumbar paravertebral vessels varies, especially at L4/L5, and may be more prone to intraoperative injury in female subjects.</p>