INTRODUCTION: Clinical and epidemiological studies have shown that cardiovascular diseases, including atherosclerosis, are associated with lumbar disc degeneration and low back pain. Atherosclerosis can obstruct lumbar arteries that supply the lumbar spine. However, the direct effect of impaired flow in lumbar arteries on intervertebral disc (IVD) matrix changes has not been examined. The purpose of this study was to evaluate IVD matrix changes in a rabbit lumbar artery ligation model using magnetic resonance imaging (MRI) T2 values.
METHODS: New Zealand White rabbits (n=15, 12‐weeks‐old) were used in this study. The abdominal aorta was exposed and the third and fourth lumbar arteries that arise from the aorta were ligated using vascular clips. The blood flow of the L3/L4 disc was diminished by ligation of the third lumbar artery, and the L5/L6 disc by ligation of the fourth lumbar artery, while the L4/L5 disc, by the ligation of the third and forth lumbar arteries. The L2/L3 disc was used as the control disc. Disc height was radiographically monitored biweekly. At 4‐, 8‐, 12‐ weeks after surgery, five rabbits were sacrificed and processed for T2 value analysis (axial 3.0‐MRI).
RESULTS: There were no significant changes in disc height over the experimental period. The T2 values of the ID, BD and SD decreased at 8‐weeks (ID: 90.1%, BD: 77.6%, SD: 85.0%), with the magnitude of change being greatest in the BD. However, at 12‐weeks, the T2 value of BD and SD recovered to a level approaching 90% of the control disc (ID: 89.2%, BD: 85.0%, SD: 90.1%).
DISCUSSION: The results of this study showed that diminished flow in the lumbar arteries affects changes in T2 values in the corresponding IVD. The recovery of T2 values at 12‐weeks would be attributed to the development of collateral arteries surrounding the lumbar spine.