Table 1 Rydell classification
From: Salvianolic acid B reduced the formation of epidural fibrosis in an experimental rat model
Grade 0 | Epidural scar tissue was not adherent to the dura mater. |
Grade 1 | Epidural scar tissue was adherent to the dura mater, but easily dissected. |
Grade 2 | Epidural scar tissue was adherent to the dura mater and difficultly dissected without disrupting the dura matter. |
Grade 3 | Epidural scar tissue was firmly adherent to the dura mater and could not be dissected. |