Fig. 1

Endoscopy diagrams of the OSE technique. A Intraoperative operation by the attending surgeon, with both working and observation channels in the same soft incision (arrow); B Removal of a portion of the lamina (triangle) and the ligamentum flavum (arrow); C Herniated disc tissue (arrow) compressing the dural sac; D Incision of the annulus fibrosus (triangle) and removal of herniated disc tissue (arrow); E Nerve root (arrow) decompression; F Decompression of the dural sac(arrow), with the triangle for epidural fat