Fig 3.

Fluoroscopic details of the technique of the transforaminal approach. A, The craniocaudal angulation in the sagittal plane is estimated on the lateral projection to point the 18-ga needle (white arrow) used as a landmark on the skin of the patient toward the posterior and inferior parts of the foramen. B, The 35° oblique view (from the anterior-posterior view) is then used to define the distance of the entry point laterally. The 18-ga spinal needle (arrow) should be pointed toward the lateral part of the facet joint (dotted line). C, The needle is advanced in the oblique view toward the foramen. D, Once in the vicinity of the foramen, the lateral view confirms that the needle enters it at its posterior and inferior parts. E, Satisfactory localization of the needle tip (arrow) inside the foramen is confirmed on anterior-posterior projection. F, The 28-ga thermosensor (dotted arrow) is gently advanced into the canal until it reaches the midline (G), where resistance is felt. H, At this point, the tip of the thermometer (dotted arrow) should be located at the middle portion of the vertebral body on the lateral view.