Fig. 2.

Axial (a) and sagittal (b) MRI images in a patient with disc herniation with extrusion and segmental instability 38 months after primary surgery. There is epidural fibrosis (black arrow). Axial (c) and sagittal (d) preoperative CT images. The primary surgery consisted of L4–L5 discectomy with a partial laminectomy of L4 (white arrow). e Intraoperative picture showing a modified dissector used to release the drug locally (black arrow). f Intraoperative picture. h Postoperative radiographs