technique

The procedure is started with sterile preparation with aseptics (Iodine) of the skin. The skin's subcutaneous, lumbar muscles are infiltrated by local anethesia (1% lidocaine) with a 22-gauges 9 cm long needle. The position of the 22-gauge needle is checked by fluoroscopy and CT.

• For cervical level : The patient is placed in supine position, head slightly turned and in hyperextension. The entry point and the pathway are determined by CT. After local anesthesia of the skin, a 22-gauge 9.5 to 12.5 cm spinal needle is placed by an antero-lateral approach in the center of the disk under dual CT and fluoroscopy control. Under precise CT control the puncture of the carotid is avoided.
• For lumbar level : The patient is placed in prone position. The entry point and the pathway are determined by CT. The skin's subcutaneous layer and lumbar muscles are infiltrated by local anethesia (1% lidocaine) with a 22-gauge 9 cm long needle. The tip of the 18-gauge needle is placed to reach the articular process, the position of the needle is checked by fluoroscopy and CT. The stylet of this needle is then removed and a 22-gauge 20 cm needle is inserted into the 18-gauge needle. The tip of the 22-gauge spinal needle is placed in center of the disk. The position of the needle is checked by fluoroscopy and CT.
  Contrast agent injection and memory pain test
• 1 to 2 ml of contrast agent are injected for lumbar level ; 0.3 to 0.5 for cervical level. The patient is asked to describe the pain reproduction and radiation during injection. Memory pain is positive if injection reproduces his leg or back pain.