It is important, among other items, to inquire as to the allergy history of the patient, prior to proceeding with any invasive injection of the facet joint. Specifically, providone iodine based skin preparation agents, iodine-based arthrography contrast agents, local anesthetic agents, steroids, and agents used for preserving various pharmaceuticals may all be present for utilization during portions of this procedure. Specific investigation as to whether there is a history of latex allergy should be made, as some arthrogram kits come complete with latex gloves or other latex-containing devices, such as syringes, included. Many liquid pharmaceuticals are secured in the bottle by rubber-containing stoppers, which must be removed and not transversed with the injection needle for such patients, for example. Alternatives exist for most of these agents, and utilization of substances to which the patient may be allergic is contraindicated, especially because they can lead to such life-threatening reactions as anaphylaxis in certain individuals.
Facet joint injection can be performed safely in the outpatient setting. No premedication is otherwise indicated in the absence of allergy to the materials being utilized. Few side effects are reported from the local injection of anesthetics or steroids (34). Steroid injections can produce local reactions, lasting 24-48 h, and can frequently be relieved by applying an ice pack. Septic arthritis, a potential major complication, can be avoided with strict adherence to aseptic technique. As degenerative disease of the facet joints usually affects multiple levels, multilevel injections are frequently provided bilaterally.
Facet joint injection is performed under the radiologic guidance of fluoroscopy. The patient is placed in the prone position on the fluoroscopy table. For lumbar facet joint injections, a pillow can be placed under the patient's abdomen, so as to achieve a more flexed spine. To best view the facet joint in the tangential plane, the patient, or, where possible, the image intensifier is rotated obliquely until the facet joint of interest is centered in the field of view and the joint space visualized. To minimize irradiation to the physician's hands and other anatomy, a metallic localization probe can be used as a pointing device, and, under fluoroscopy, the desired location for needle placement can be found on the patient's skin, thereafter being marked with an indelible skin marking pen.
The skin under and around the marked site is prepared and draped in standard, sterile fashion, utilizing a providone iodine based skin prep when possible and an isopropyl alcohol based prep for patients with an iodine allergy. At least three sterile washes are made on and about the area to be injected and instrumented. Following air drying of the skin preparation agent, the sterile drapes are placed into position. Using a small (3- or 5-cc) syringe and a small 25-gauge injection needle, a skin wheal is made using 1% or 2% lidocaine, through which slightly deeper anesthesia may be given, depending on the body habitus of the patient. The 25-gauge needle is left in place in the skin, to confirm the desirability of the chosen site of injection.
The 25-gauge anesthetizing needle is replaced with a 20- or 22-gauge spinal needle. As the facet joints are curved, the joint can be divided visually into an anteromedial and a posterolateral half. Because the needle must transverse the posterolateral aspect of the joint, a shallow obliquity to the needle is best. The obliquity necessary for successfully intubating the facet joint varies by level, for example, being as little as 30° for an upper lumbar level joint, while as great as 60° for a lower lumbar level joint. The needle is advance under fluoroscopic guidance until the tip hits bone or cartilage, and is then repositioned until it slips into the center of the joint space (Figs. 5 and 6). The needle tip placement can be checked further by lateral (orthogonal) fluoroscopy. In cases in which the aforementioned technique is unsuccessful, or where the facet joint is difficult to appreciate fluoroscopically, or where severe osteoarthritis blocks the needle from entering the joint space, the needle can be directed toward the inferior recess of the facet joint, a synovial outpouching that projects inferior to the tip of the inferior articular facet (35). The adequate position of the needle tip can be confirmed with an injection of a minimal amount (0.1 cc) of nonionic contrast (180 mg/dl of iohexol [Omnipaque]; Nycomed, Princeton, NJ), as the capacity of the synovial joint may be only 1-2 cc (36). An attempt to aspirate the contrast following arthrogram should be made prior to any pharmacotherapy.
Pharmaceutical therapy of the facet joint routinely involves the utilization of both an anesthetic agent and a steroid agent. Both agents are generally drawn into a single syringe for simultaneous intraarticular injection. Just such a steroid-anesthetic mixture might include 0.5 cc of meth-ylprednisolone acetate (Depo-Medrol) with 2 cc of 0.25% bupivacane hydrocloride (Marcaine) for each separate joint injected. With the joint space so small, injection is terminated when resistance to further injection is encountered, to avoid capsular rupture.
Various local anesthetic agents that have been utilized for joint space injection include 5-25 mg of Xylocaine (lidocaine), 10-50 mg of Carbocaine (mepivacaine), 2.512.5 mg of Sen-sorcane (bupivacaine), and 2.5-12.5 mg of Marcaine (bupivi-caine). Various long-acting steroid agents that have been utilized for joint space injection include 1.5-3 mg of Celestone suspension (betametha-sone sodium phosphate and beta-methasone sodium acetate), 2-6 mg of an Aristospan suspension (triamcinolone
hexacetonide), and 4-10 mg of Hydeltranol (prednisolone tebutate). Care must be taken to ensure combinations of agents are combatable to be admixed to avoid such potential incompatibilities leading to precipitation or floc-culation (19).
For cervical facet joint blocks, the skin puncture point is selected two to three segments below the target level, as the joint space slopes posteroinferiorly. The needle is then advanced craniad and ventrally toward the target joint. As the needle tip articulates with the inferior margin of the joint, it can be passed into the middle of the joint space, as confirmed on posteroanterior and lateral imaging. It is important to remember that the epidural space rests just medially to the anatomy under investigation, with spinal nerves and vertebral arteries also in close proximity.
If CT-guided injection is being utilized, the patient is placed on the CT table in a prone position. Contiguous axial views can be obtained through the facet joint. Under CT, the proposed site of skin puncture can be marked utilizing an opaque or metallic marker, such as a paper clip. Once a proposed site is chosen, the skin can be marked with an indelible marker and thereafter prepped and draped in a similar fashion as described in the preceding. A procedure and instruments similar to those described in the preceding for fluoroscopic guidance can be used with CT as the guidance modality.
Was this article helpful?