Fig 2.

Representation and principle of the double-oblique approach. A, Drawing from a sagittal perspective. The craniocaudal approach in the sagittal plane enables going through the posterior and inferior parts of the foramen, away from the radicular nerve and vessels. B, Drawing from an oblique axial view (in the axis of the sagittal angulation). The lateromedial approach allows slipping along the facet joint with the 18-ga needle (arrow), away from the nerve and vessels (arrowhead). The 28-ga thermosensor (dotted arrows) can then be advanced into the anterior epidural space toward the posterior wall of the vertebral body.