Objective: To investigate epidural fat distribution patterns in patients with lumbar intervertebral disc protrusion. Methods: Medical records were selected randomly from 30 patients whose diagnoses were consistent with the inclusion criteria of the study. Thickness of bilateral fat

the longest length of posterior fat

thickness of bilateral yellow ligament and the hernial distance of lumbar discs were measured by MRI at L3/L4

L4/L5 and L5/S1 levels. According to clinical symptoms of lumbar intervertebral disc protrusion

the patients were divided into two groups at all space levels. All data were analyzed by statistical software. Results: The longest length of posterior epidural fat at the symptomatic levels was shorter than that at the non-symptomatic levels in each disc space. The symptomatic levels had no effect on the whole thickness of the lateral fat and lateral yellow ligaments. Conclusion: Epidural fat distribution in patients with lumbar intervertebral disc protrusion is different from that in normal adults. It is affected by the hernial distance of lumbar discs. The diagnostic criteria for spinal epidural lipomatosis in normal adults may therefore prove to be inappropriate for patients with lumbar intervertebral disc protrusion.