From: Spinal epidural lipomatosis presenting to a U.S. Veterans Affairs pain and rehabilitation department: a report of two cases
Grade I
Grade II
Grade III
Dural Sac Diameter ÷ Epidural Fat Diameter
1.49–1
0.99–0.34
≤0.33
Epidural Fat Diameter ÷ Spinal Canal Diameter
41–50%
51–74%
≥75%