Thoracic selective injections are performed with the patient in prone position. The X-ray beam is tilted laterally such that a "Window" is created allowing access between the facet joint, pedicle, transverse process, and rib (Fig. 1). The beam is tilted cranio-caudally such that it is directed "down the barrel" of the pedicle, the lower margin of which is about halfway between the end plates. The area is prepped and draped, the skin entry site is localized fluoroscopically, and subcutaneous lidocaine is administered. Deeper, lidocaine is administered along the angle of the X-ray beam. Next, a 22- or 25-gauge spinal needle is advanced inferior to the pedicle through the aforementioned "Window" until the posterolateral vertebral body is reached or
FIGURE 1 Localization for thoracic selective epidural injection: fluoroscopic and computed tomography (CT) methods. (A) Fluoroscopic image showing obliquity required for needle placement. Note pleural margin (arrowheads) and vertebral pedicle (letter "P"). Optimal needle course between the rib, facet joint, and pedicle is marked with an asterisk. Care must be taken not to pass the needle medial to the medial edge of the pedicle (arrow), which demarcates the spinal canal. (B) Axial CT image of needle tip (arrow) positioned within a thoracic neural foramen. Localization is performed using the same basic technique as for a CT-guided biopsy.
radicular pain is perceived. If there is severe radicular pain, the needle should be repositioned. Care must be taken to avoid the pleural margin more laterally, which is easily visualized fluoroscopically. The needle should not be advanced more medial than the medial margin of the pedicle, which forms the border of the spinal canal.
If there is any blood return from the needle, the tip should immediately be repositioned; in the thoracic spine, especially from T7 to T9, small arterial feeders to the spinal cord can extend through the superior aspect of the neural foramen. Injection of air, lidocaine, or particulate steroid into these branches has the potential to cause cord infarction. For this reason we also position the needle more inferiorly within the neural foramen, because the feeding vessels run just below the pedicle. Next, contrast injection is performed to verify satisfactory positioning. A "Wet" connection is important to assure that no air is injected (in case of intravascular positioning). The injected contrast should extend centrally into the lateral epidural space of the spinal canal, and peripherally around the nerve root. If there is vascular opacifi-cation, the needle should be repositioned. If the patient complains of an acute onset of severe radicular pain immediately upon injection, an intraneural injection may have occurred; injection should be stopped immediately and the needle should be repositioned. After proper positioning is verified, the anesthetic and steroid mixture is injected with periodic fluoro-scopic observation.
Was this article helpful?
Deal With Your Pain, Lead A Wonderful Life An Live Like A 'Normal' Person. Before I really start telling you anything about me or finding out anything about you, I want you to know that I sympathize with you. Not only is it one of the most painful experiences to have backpain. Not only is it the number one excuse for employees not coming into work. But perhaps just as significantly, it is something that I suffered from for years.