Table 1

- Histopathological classification of epidural fibrosis.23

GradesCriteria
Grade 0No fibrosis affecting the dura mater
Grade IOnly a thin fibrous band between the scar tissue and dura
Grade IIAdhesion continues to progress but does not cover the entire laminectomy defect (less than 2/3)
Grade IIIScar tissue adhesion is larger, constituting more than 2/3 of the laminectomy defect or extending to the nerve root