Chapter 67. Intra-Articular Injections and Facet Blocks

The use of systemic corticosteroids for the treatment of symptomatic arthritis began shortly after the discovery and synthesis of cortisone in the 1940s.1 Intra-articular steroid injections followed shortly thereafter. In 1951, Hollander published the results of a large series of patients treated with corticosteroid joint injections. Since then, corticosteroid injections have played an important role in the diagnosis and management of acute and chronic joint and periarticular pain problems.

Intra-articular and periarticular injections are indicated for diagnostic, prognostic, and therapeutic purposes (Table 67-1).

Diagnostic Injection

A careful history, physical examination, and supporting radiographic studies are important in the evaluation of a patient with a pain complaint, but often these three components of the evaluation fail to identify the source or sources of the patient’s pain. Despite some limitations, a series of accurately performed local anesthetic injections often is the best diagnostic “test” we have to identify the pain generator(s) contributing to the patients pain problem.

Prognostic Injection

Injection techniques may help to determine if a more definitive therapeutic intervention is indicated. Pain relief following a local anesthetic injection into an arthritic joint may lead to consideration of viscosupplementation or may convince a surgeon that an operation is indicated (Fig. 67-1). The decision to perform total joint replacements or bursectomies frequently is guided by the response to one or more diagnostic injections.

Prognostic injections may help to determine if a joint denervation procedure is indicated. Chronic facet pain and discogenic pain often are treated with denervation procedures (e.g., radiofrequency). A denervation procedure is performed following a series of carefully controlled prognostic local anesthetic blocks.

Therapeutic Injection

Injections are used to treat a variety of inflammatory and noninflammatory joint and periarticular soft tissue pain problems.

Rheumatoid Arthritis

Rheumatoid arthritis is a chronic systemic inflammatory disease with polyarticular involvement. Because this is a systemic disease, the principal therapeutic agents are systemic anti-inflammatory and/or immune modulating drugs. Injection of isolated joint flare-ups with local anesthetic and corticosteroid may help to quickly restore function and allow participation in physical therapy. Studies have demonstrated short-term pain relief and improved periarticular muscle strength in patients following intra-articular corticosteroid injection of a symptomatic rheumatoid joint.3,4 For a flare-up of a single or a couple of joints, it is preferable to inject one or two joints rather than to increase the dose of systemic agents or to add an additional systemic agent.

Osteoarthritis and Other Joint Conditions

The treatment continuum for osteoarthritis ranges from conservative therapy, including physical therapy and oral medications on one end, to total joint replacement on the other end. Injection therapy with corticosteroids or viscosupplementation may be used for the treatment of symptomatic flare-ups or treatment in patients who are poor surgical risks. Patients with severe bone-on-bone osteoarthritis may not respond or may have only minimal response.

Intra-articular corticosteroid injection and intra-articular viscosupplementation typically provide several weeks to months of relief.5,6 This period can be used as a therapeutic window for an appropriate rehabilitation and exercise program. Small and non-weight-bearing joints have a longer duration of relief than large weight-bearing joints following corticosteroid injection for osteoarthritis.

Corticosteroid injection has been reported in case reports and anecdotal series to be effective in the relief of other painful joint conditions including psoriatic arthritis, lupus, crystalline arthritis (gout and pseudogout), and Reiter’s disease.

Periarticular Injections

The injection of local anesthetic and corticosteroids is extremely effective in the treatment of bursitis and tendonitis. Unlike corticosteroid joint injections in which the relief tends to be short-term and temporary, symptomatic tendon and bursa inflammation typically have a longer period of relief and a significant “cure” rate if therapy is initiated early and combined with an appropriate rehabilitation program.7,8Table 67-2 lists the most common indications for periarticular soft tissue injections.

Contraindications

Infection in the area to be injected is the major absolute contraindication. If a joint infection is suspected clinically, a sample of synovial fluid should be aspirated and analyzed prior to performing an intra-articular injection. Documented allergy to the injectant is the only other major contraindication.

Joint injection in the presence of a coagulopathy or in patients taking systemic anticoagulants is somewhat controversial. A recent study of 32 injections and aspirations performed in patients taking therapeutic warfarin resulted in no cases of joint or soft tissue hemorrhage.9 This was a small study but it did demonstrate that the risk of significant hemorrhage was minimal after a carefully performed injection in patients taking systemic anticoagulants.

Corticosteroids continue to be the most commonly used therapeutic injectant. Viscosupplementation, the local injection of a viscous fluid containing hylan polymers, is commonly used to treat symptomatic osteoarthritis of the knee. Many other analgesics, anti-inflammatory, and immune modulating agents have been injected with varying success.

Corticosteroid Injection

A variety of corticosteroids are available for joint and periarticular injection. The duration of analgesic and anti-inflammatory effects is inversely related to their aqueous solubility (Table 67-3). In general, the duration of effect for triamcinolone hexacetonide, the longest duration agent, is approximately 3 to 6 weeks. Pharmacokinetic studies have shown it to be absorbed from the joint over a period of 2 to 3 weeks.10 On the other end of the spectrum, hydrocortisone acetate has a clinical duration of less than 1 week and is completely absorbed from the joint in less than a day.

The putative mechanisms of symptomatic relief from injected corticosteroids include an anti-inflammatory or disease-modifying effect, an analgesic effect, systemic effects following systemic uptake, and a local neuronal suppressive effect.

Intra-articular steroids have been demonstrated to reduce synovial inflammation in patients with rheumatoid arthritis.11 Similarly, they have been shown to have a favorable disease-modifying effect in osteoarthritis joints.12 Local application of corticosteroids around damaged or inflamed nerves has been shown to suppress neural discharge and symptoms of neuropathic pain.13,14 Corticosteroids also have been shown to promote the secretion of a surface-active phospholipid into the joint, which acts as a joint “lubricant” and may contribute to improved joint mobility.15

Most corticosteroids are injected along with a local anesthetic to minimize the injection and post-injection pain and to provide immediate feedback regarding the effectiveness of the injection. Most local anesthetics are compatible with injectable corticosteroids; however, most manufacturers recommend the use of methylparaben-free and preservative-free anesthetics to reduce the extent of clumping or flocculation of the agent. Table 67-4 lists the relative potencies of the more commonly used agents and Table 67-5 lists dosage guidelines.

Viscosupplementation

The synovial fluid of osteoarthritic joints has been shown to be significantly less viscous than normal, at least in part due to a decreased concentration of hyaluronic acid. It is presumed that this reduces the protective function of the synovial fluid.

Viscosupplementation is the injection of hyaluronic acid derivatives into the synovial fluid of an osteoarthritic joint. Many clinical studies have demonstrated significant clinical improvement and increased synovial fluid viscosity and hyaluronic acid concentration following a series of these injections. Side effects have been minimal and typically involve a brief period of pain and swelling.

Two agents currently are approved for viscosupplementation therapy of symptomatic osteoarthritic knees. Trials involving therapy of joints other than the knee are under way. Hylan G-F 20 (Synvisc) is a viscous fluid containing hylan, which is manufactured from sodium hyaluronate, extracted from chicken combs. It is supplied in 2-mL prefilled syringes and is administered as an intra-articular knee injection 1 per week for 3 weeks.

Hyalgan also is manufactured from sodium hyaluronate from chicken combs. It is administered as an intra-articular knee injection 1 per week for 5 weeks.

Viscosupplementation has been shown to be as effective as oral nonsteroidal anti-inflammatory agents (NSAIDs).16–18 The average duration of effect is approximately 6 months and ranges from 2 to 18 months. As this is a relatively new treatment, its role in the treatment of osteoarthritis is evolving. It may be considered as a first line of treatment in patients who cannot take NSAIDs or who do not respond to NSAIDs. It may be an adjuvant agent in patients who are taking NSAIDs.

The main difference between Hyalgan and Synvisc is the viscosity of the preparation. Synvisc has a higher molecular weight and viscosity than Hyalgan, and is very similar to that of synovial fluid. It is not known if this results in differences in efficacy as comparative studies have not been done.

Other Injectants

Injection of beta-emitting radiopharmaceutials into rheumatoid joints with active disease has been shown to produce a radiation-induced synovectomy and is effective in controlling symptoms.19,20 The technique has not gained widespread use or acceptance because of radioactive leakage from the joint to nontarget organs. Studies are currently under way; looking at new radiopharmaceuticals that may minimize such leakage.20

Photodynamic therapy is a promising new therapy, which may be effective for the treatment of arthritis. Injection of hydrophobic photosensitizers may be preferentially absorbed by hypervascular inflamed synovium, which then is targeted for destruction by laser techniques. This technique is well established for the treatment of certain neoplasms, and currently is being investigated for treatment of inflammatory arthritis.21

Side Effects and Complications

The three major concerns with corticosteroid joint injections are infection, joint and/or periarticular tissue damage, and systemic side effects. By using sterile technique and disposable needles and syringes, the risk of infection is remote. Several large series have demonstrated the risk of infection to be 1:50,000 injections or less.22

Systemic absorption occurs following corticosteroid joint injection. Possible systemic side effects include virtually any side effect or untoward effect that has been reported to accompany systemic steroid administration. Practically speaking, using the lowest effective dose and limiting the number of injections minimizes the risk. Patients with diabetes may see a temporary (1 week) rise in blood glucose. Dosages >40 mg of triamcinolone may transiently suppress the hypothalamic–pituitary–adrenal (HPA) axis. Fluid retention, weight gain, and facial flushing have been reported following corticosteroid injection.23

Many clinicians assume that corticosteroid injection exposes patients to a significant risk of tendon or periarticular bone or cartilage damage. Some of these concerns were initiated by anecdotal reports of “steroid arthropathy” and subprimate animal studies demonstrating bone and tendon pathology following corticosteroid injection.24,25

More recent human studies and primate animal studies have shown that within reasonable dosage limits, corticosteroid injections do not weaken tendons or damage bone and cartilage. In fact, recent studies have demonstrated an articular protective effect in inflammatory arthritis and steroids may actually suppress the formation of painful osteophytes in osteoarthritis.12,26–28 The risks and benefits of joint injection can be balanced by following the dosage guidelines in Table 67-5 and limiting injections to less than 3 to 4 per joint per year.

Shoulder Injections

Injection of the Shoulder Joint

This injection may be performed with or without fluoroscopy. Studies of major joint injections (knee, hip, and shoulder) have shown significant rates of failure to localize the joint when fluoroscopy was not used.29

When performed without fluoroscopy, the patient is placed sitting or supine with the shoulder externally rotated. The point of entry is marked just medial to the head of the humerus and just below (inferolateral) the coracoid process (Figs. 67-2 and 67-3). After sterile skin preparation, the skin and subcutaneous tissues are anesthetized with lidocaine using a 27- or 30-gauge needle. Then a 22-gauge 1½- to 2½-in. needle is advanced posteriorly with a slight superolateral angle. The resistance of the joint capsule will be obvious. The needle is advanced until it “pops” through the capsule and is advanced 0.5 cm. After careful aspiration, 2 to 3 mL of anesthetic-corticosteroid suspension is injected. If pressure is encountered during injection, the needle should be repositioned slightly medially.

Never inject any joint if resistance is encountered, as the needle ending may be in ligament, tendon, or cartilage and these structures can be damaged by mechanical disruption from a direct injection. Aspiration is important prior to injecting the agent, as it is possible for the needle to enter the axillary or subclavian vessels.

A posterior approach may also be used. The patient is in the sitting position with the arm internally rotated and adducted. This is best accomplished by having the patient place the hand of the arm to be injected on the opposite shoulder. The needle entry point is marked just under the posteroinferior border of the acromion. After sterile preparation and local anesthesia, a 22-gauge 2½-in. needle is advanced anteriorly with a slight cephalomedial angle (Fig. 67-4 and 67-5). Again, the needle is advanced 0.5 cm through the capsule and anesthetic–corticosteroid suspension is injected.

Intra-articular shoulder joint injections are used chiefly for diagnostic purposes to help determine if the shoulder joint is contributing to a patient’s pain problem. There is insufficient data to determine whether or not shoulder injections have long-term therapeutic value.30

Injection of the Subacromial Bursa

This injection can be performed using a lateral or posterior approach. Using the lateral approach, the needle entry site is marked on the lateral shoulder just inferior to the acromium. A 22-gauge 1½-in. needle is advanced toward the inferior border of the lateral acromium (see Fig. 67-2). After the needle contacts the acromium, it is “walked” inferiorly until it slips off the inferior edge of the acromium. Then it is advanced 0.5 to 1.0 cm and 2 to 3 mL of anesthetic-corticosteroid suspension is injected.

The posterior approach is the preferred approach because there is a larger space between the acromium and humeral head. The point of entry is marked 1 cm below the posterior acromium, at or just medial to the angle of the acromium (Figs. 67-4 and 67-6). A 22-gauge 1½-in. needle is advanced anteriorly with a slight cephalomedial angle to contact the acromium. The needle is walked inferiorly until it slips off the inferior edge and then it is advanced 0.5 to 1 cm. If resistance is encountered during the injection, the needle should be repositioned, as the needle may be in the supraspinatous tendon. This tendon is fragile and could be damaged by an intra-tendinous injection.

Injection of the Acromioclavicular Joint

The joint space is palpated as a groove or depression between the acromium and clavicle on the top surface of the shoulder. This groove is marked, and after sterile preparation and local anesthesia, a 22-gauge 1½-in. needle is advanced into the joint space (Figs. 67-2 and 67-7), then 0.5 mL of injectant is placed into the joint.

Elbow Injection

Elbow Joint Injection

The elbow joint is injected using a lateral approach. The radial humeral joint can easily be palpated laterally at level of the skin crease of the elbow.

The lateral epicondyle of the humerus is the most obvious identifiable landmark. Identify this with the examining finger and then slide the finger down the epicondyle until the groove between the epicondyle and the plateau of the radius is felt. Mark this spot as the needle entry point (Figs. 67-8 and 67-9). After sterile skin preparation and cutaneous anesthesia, a 22-gauge 1½-in. needle is advanced through the needle entry point and advanced to contact the distal epicondyle. Then walk the needle distally until it slides off the epicondyle and into the joint space. Advance the needle 0.5 cm and inject 1 to 2 mL of injectant. If an ulnar paresthesia is elicited during this block, the needle is too dorsal and a more volar approach should be used.

Olecranon Bursa Injection

The olecranon bursa is a large bursal sac between the soft tissue and the olecranon process of the ulna. After sterile skin preparation and cutaneous anesthesia, a 25-gauge 1- to 1½-in. needle is advanced in a direction perpendicular to the olecranon (see Fig. 67-8) until the olecranon surface is contacted. Then the needle is withdrawn approximately 1 to 2 mm and 1 to 2 mL of injectant is placed at the site. To avoid a subcutaneous injection, do not withdraw the needle too far after contacting the olecranon.

Hand and Wrist Injections

Finger Joint Injections

The carpometacarpal (CMC), metacarpophalangeal (MCP), and interphalangeal (IP) joints commonly are affected by rheumatoid and osteoarthritis flare-ups and are amenable to injection therapy. The specific joint to be injected can easily be palpated. For the IP joints, a lateral or medial approach is used. For the MCP or CMC joints, a dorsal approach is used. It is best to avoid the more richly innervated volar (palmar) surface of the hand, as these injections are more painful.

A 27-gauge 1½-in. needle is advanced into the joint space. It only needs to enter the superficial joint, just through the capsule (Figs. 67-10 and 67-11). Inject 0.5 mL of anesthetic-corticosteroid solution.

Wrist Injections

A dorsal approach to the radiocarpal and ulnocarpal joints is preferred. These joints can easily be palpated and the needle entry site marked (Figs. 67-10 and 67-12). Care should be taken to avoid the extensor tendons. The joint space can be “opened up” slightly by placing the wrist in 45 degrees of flexion. After sterile skin preparation and local anesthesia, a 22-gauge 1½-in. needle is advanced into the joint. Again, the needle should be advanced into the superficial joint and 1 to 2 mL of solution injected.

Hip Injections

Hip Joint Injection

Intra-articular hip joint injections usually are performed diagnostically to help determine if hip arthritis is contributing to a patient’s pain problem and prognostically to help determine if total hip arthroplasty would be beneficial.31 The duration of pain relief after intra-articular corticosteroid hip injection typically is 1 to 3 months in patients with symptomatic osteoarthritis.31,32

The hip joint can be injected from an anterior or lateral approach. The use of fluoroscopy is highly desirable. A lateral or anterolateral approach results in a more favorable needle trajectory for joint entry.

The patient is placed supine on the fluoroscopy table with the hip internally rotated (toes and knees pointed inward). The needle entry point is just anterior and cephalad to the greater trochanter (Fig. 67-13). Using fluoroscopy, the needle is directed medially and slightly cephalad (Figs. 67-13 and 67-14). The joint capsule is quite thick and easily identified with the needle. The needle is advanced just through the capsule. Aspirate to be sure the needle has not entered the femoral vessels. Two milliliters of radiopaque contrast can be injected to confirm placement. This is followed by placing 2 to 3 mL of injectant into the joint.

Trochanter Bursa Injection

The trochanteric bursa is a large bursal sac located between the lateral surface of the greater trochanter and the overlying iliotibial band (see Fig. 67-13). It is a common cause of lateral thigh pain and responds well to local anesthic-corticosteroid injection.33

The injection is performed by placing the patient in a lateral position with the symptomatic side up (Fig. 67-15). The area of maximal trochanteric tenderness is marked. After sterile skin preparation and cutaneous anesthesia, a 22- or 25-gauge 2½- to 3½-in., needle is directed perpendicular to the trochanter and advanced until bone is contacted. Then the needle is withdrawn 3 to 5 mm and 3 to 5 mL of solution is injected.

Iliopsoas Bursa Injection

The iliopsoas bursa is the largest bursa in the body and lies between the iliopsoas muscle and the anterior hip capsule (see Fig. 67-13). It is a common but often overlooked cause of groin pain.34,35 There may be direct communication between the bursa and the joint.

The injection is performed with the patient supine. The needle entry site is just below the inguinal ligament and 1 to 2 cm lateral to the neurovascular bundle (femoral artery pulsation) to avoid needle trauma to the femoral nerve and vessels (see Fig. 67-13). After sterile skin preparation and anesthesia, a 22-gauge 3½-in. needle is advanced perpendicular to the skin and advanced until the anterior bone of the acetabulum is contacted. The needle is then withdrawn 3 to 5 mm, and after careful aspiration, 3 to 5 mL of solution is injected. If blood is aspirated, or a femoral nerve paresthesia occurs during needle placement, re-direct the needle 1 to 2 cm laterally. Be sure to check the patient for femoral nerve anesthesia prior to allowing ambulation.

Knee Injections

Knee Joint Injection

Intra-articular knee joint injection can be valuable diagnostically to help determine the contribution of the joint versus periarticular structures in a patient with knee pain. It can be therapeutic in patients with rheumatoid arthritis by suppressing pain and inflammation in an acute flare-up.36 It can provide short-term relief (2 to 4 weeks) in patients with symptomatic osteoarthritis.37 This will allow time for affected patients to participate in an appropriate rehabilitation program.

Knee joint injection can be performed using either an anterior or a medial approach. For the more commonly used medial approach, the patient is placed supine with the leg straight or slightly flexed. The needle entry site is identified and marked as follows. The medial border of the inferior patella is identified. The needle entry site is 1 cm medial to this (Figs. 67-16 and 67-17). After skin preparation and local anesthesia, a 1½- to 2-in. 22-gauge needle is advanced to contact the medial edge of the patella. Then it is walked off the patella and advanced between the patella and the medial femoral condyle and 2 to 3 mL of solution is injected.

For an anterior approach, the patient is seated with the knee flexed. The needle entry point is marked on the anterior surface of the knee as a point just below the inferior pole of the patella and just medial to the inferior patella tendon (Figs. 67-16 and 67-18). After sterile preparation and skin anesthesia, a 1½-in. 22-gauge needle is advanced perpendicular to the skin until bone is contacted. The needle is then withdrawn 0.5 cm and 2 to3 mL of solution is injected.

Patellar Bursa Injection

The prepatellar bursa lies between the patella and the overlying soft tissue. Prepatellar bursitis is a common cause of localized knee pain and responds well to local injection and rest.38 Local injection is not much more than a trigger point injection. After skin preparation and local anesthesia, a 25-gauge needle is advanced until it contacts the patella (see Fig. 67-16). Then it is withdrawn 2 to 3 mm and 1 to 2 mL of solution is injected.

Anserine Bursa Injection

The anserine bursa lies between the medial knee joint and the pes anserinus (tendons of the semitendinous, graclis, and sartorius muscles). Anserine bursitis is a common cause of medial knee pain and it responds well to injection therapy.39

The injection technique is quite simple and is similar to a trigger point injection. The area of maximal tenderness is identified over the medial tibial plateau and marked. After skin preparation and anesthesia, a 25-gauge 1- to 1½-in. needle is advanced until bone is contacted (see Fig. 67-16). The needle is withdrawn 2 to 3 mm and 1.0 mL of solution is injected.

Foot and Ankle Injection

Ankle Injection

The ankle joint is entered from an anterior approach to enter the joint between the tibia and the talus. The patient is positioned supine with the leg‐foot angle placed at 90 degrees. The point of entry is just medial to the anterior tibial and extensor hallicis longus tendons on a line drawn between the medial and lateral malleoli (Figs. 67‐19 and 67‐20). These tendons can be easily identified by having the patient dorsiflex the foot and great toe. After skin preparation and anesthesia, a 1‐in. 22-gauge needle is advanced directly posteriorly until bone is contacted. The needle is then walked inferiorly until it slips between the tibia and talus. One to two milliliters of solution is injected. Joints between the tarsal bones are best injected by using fluoroscopic guided injection.40

Forefoot Injections

The injection technique for metatarsal phalangeal and interphalangeal joints is exactly the same as the techniques described for the IP and MCP joints on the hand (see Fig. 67-19). Again, a lateral or dorsal approach is usually favored over the more painful plantar approach.

Sacroiliac Joint Injection

In patients with acute spondyloarthropathies, an inflammatory sacroiliac component may be present. More often, sacroiliac joint pain occurs as a result of injury. Diagnostic sacroiliac injections are considered an important part of the diagnostic workup for mechanical low back pain because history and physical examination are notoriously unreliable.41

Sacroiliac joint injection can be performed with or without the use of fluoroscopy; however, when fluoroscopy is not used, there is a significant rate of failure to enter the joint. Therefore, if the block is being performed for diagnostic reasons, fluoroscopy or CT guidance should be used.

The patient is placed in the prone position. The sacroiliac joint is most accessible to injection at the most caudal or inferior portion of the joint.42,43 Attempts to enter the synovial cavity of the joint at the middle and cranial or superior portions of the joint have a higher failure rate.

Using fluoroscopy, or by palpation, the posterior superior iliac spine (PSIS) is identified. The needle entry site is approximately 1 cm below the PSIS (Fig. 67-21A and 21B). After skin preparation and local anesthesia, a 22-gauge 2½- to 3½-in. needle is advanced through the above mentioned entry site toward the joint. The correct needle angle is typically 20 to 30 degrees laterally from the sagittal plane. Upon initial entry, the needle will traverse through the thick and tough posterior sacroiliac ligament (Fig. 67-22). The needle must be advanced through this ligament to reach the synovial joint cavity. This joint cavity may be obliterated or replaced by fibrous tissue in some patients. If fluoroscopy is used, 1 to 2 mL of radiopaque contrast can be injected to confirm an intra-articular dye patter (Fig. 67-23). This is followed by an injection of 1 to 2 mL of the diagnostic or therapeutic injectant.

If fluoroscopy is not used then a larger volume is injected in order to improve the likelihood of spread to the joint. To obtain the greatest chance of joint entry, it is best to direct the needle down to the sacrum and then walk the needle laterally until the needle contact changes from bone to the tough ligamentous tissue. Because the injectant may spread to a variety of adjacent structures, including muscles, ligaments, and sacral nerve roots following an injection done without imaging guidance, diagnostic inferences should not be made following such a procedure.

Cervical Facet Injection

Atlantoaxial Joint Injection

Intra-articular cervical facet injections are performed to diagnosis and treat a variety of neck pain problems. Anatomically, the first cervical facet joint, the atlantoaxial or C1-2 joint is markedly different from the remaining five cervical facet joints and the cervical-thoracic facet joint. This joint is responsible for the majority of axial rotation in the normal cervical spine. Accordingly, suboccipital pain with rotation of the head to the left or right often is indicative of C1-2 joint pathology.

The C1-2 joint may be injected using a lateral or posterior approach.44–47 Because the vertebral artery courses along the lateral edge of the joint, the posterior approach is preferred. The patient is positioned prone on the fluoroscopy table and the fluoroscopy beam is positioned in a posteroanterior (PA) projection (Fig. 67-24). Because the teeth and jaw frequently project over the upper cervical spine, it is usually necessary to have the patient open the mouth. Once a clear view of the joint is obtained by adjusting the fluoroscopy column, the entry point is marked, sterilized, and anesthetized. Then a 3½-in. 22- or 25-gauge needle is advanced directly toward the joint with the target being the junction of the lateral one third and the medial two thirds of the joint. The needle is advanced to contact the boney edge of the joint at C2. The needle is then walked off the bone into the joint and advanced no more than 1 to 2 mm. Intra-articular placement is confirmed by the injection of 0.25 to 0.5mL of radiopaque dye suitable for myelography (e.g., iopamidol). An appropriate arthrogram should be identifiable (Fig. 67-25) and there should not be any intravascular uptake or spread to the spinal axis. This is followed by the injection of a mixture of 0.25 mL of anesthetic (recommend 1% lidocaine) and 0.25 mL of corticosteroid. The C2 nerve root runs across the posterior surface of the joint (Fig. 67-26). If a paresthesia is obtained during needle placement, it is advisable to choose a slightly different trajectory. It is usually best to make the initial needle puncture sight slightly more caudad.

Potential complications include intravascular injection, spinal axis injection, needle trauma to the nerve root or spinal cord, and vascular injury. Since most injectable corticosteroids are particulate, it is theoretically possible for a particulate cerebral embolism to occur.

Cervical Facet Joint Injection

The C2-3 through C6-7 joints can be injected using a posterior approach or a lateral approach.48,49 The posterior approach is safer but technically more difficult due to the marked cephalocaudal angulation of the joints. The lateral approach is technically easier but more risky as the advancing needle can pass through the joint and into the spinal canal. This can be prevented by frequent PA and lateral fluoroscopic views.

For the posterior approach the patient is prone and the neck is slightly flexed (see Fig. 67-24). The fluoroscopy column is adjusted to identify the target joint(s). The needle entry site should be marked one level below the target joint. This will allow angulation of the needle at an angle that will facilitate entry into the cephalocaudal oriented cervical facet joints. A 3½-in. 22- or 25-gauge needle is advanced into the joint under fluoroscopic guidance. Intra-articular placement is confirmed with PA and lateral fluoroscopy by injecting 0.25 to 0.5 mL of contrast. After proper needle placement is confirmed, and following negative aspiration, a mixture of 0.25 mL of anesthetic plus 0.25 to 0.50 mL of corticosteroid is injected.

For the lateral approach, the patient may be positioned prone, lateral, or even supine. Lateral positioning usually is preferred by the patient and is convenient for the physician (Fig. 67-27). The target joint is identified and marked using fluoroscopy. Following sterile preparation and local anesthesia, a 1½- to 2½-in. 25-gauge needle is advanced to contact bone at the inferior edge of the joint. The needle is walked off the bone and advanced 2 to 3 mm into the joint (Fig. 67-28A and Fig. 67-29). Posteroanterior fluoroscopy is used to confirm that the needle is in the lateral one third of the joint (Fig. 67-28B). The needle is withdrawn slightly if the tip is beyond the lateral one third of the joint. Injection is performed as described for the posterior approach.

Complications and side effects from cervical facet blocks include intravascular injection, spinal axis injection, joint trauma, nerve root and spinal cord trauma, infection, and side effects from the injected corticosteroid.

Thoracic Facet Joint Injection

Thoracic fact joint pain is not a common clinical problem. The thoracic facet joints are not as prone to arthritic involvement as are the cervical and lumbar facet joints. The most common cause of thoracic facet pain is trauma.

Like the lower cervical facets, the thoracic facets have a marked cephalocaudal angulation. The average angle of incline from the horizontal plane is 60 degrees in the mid-thoracic region. Accordingly, the technique for thoracic facet injection is very similar to the posterior approach to the cervical facet joint.50

The patient is placed prone and the fluoroscopy tube is angled in order to get the best view of the target joint. The needle entry site is one to two segments below the target joint to allow angulation of the needle to facilitate joint entry (Fig. 67-30A and 30B). The remainder of the technique is as described for posterior cervical facet injection.

Lumbar Facet Joint Injection

Because of the prevalence of low back pain, lumbar facet injection is one of the most commonly performed pain management procedures. Intra-articular facet injections can be performed for diagnostic or therapeutic purposes.51–53 Because of the oblique orientation of the lumbar facet joints, especially the lower two levels, it often is helpful to position the patient in a slightly oblique position with the side to be injected rotated up 30 to 45 degrees (Fig. 67-31).

With the patient appropriately positioned, the target joint is identified with fluoroscopic guidance and the skin is marked. It is best to identify the level by starting at the lumbosacral junction and then working up to the thoracolumbar junction. It is not unusual to have lumbosacral anomalies. To make communication between practitioners clear, it is important to specify the presence of any abnormalities and how it influences the counting and reporting of the level or levels injected.

After sterile preparation and local anesthesia, a 22-gauge needle is advanced under fluoroscopic guidance toward the target joint. A 3½-in. needle will be long enough for most patients; however, the larger patient may require a 5- or 6-in. needle. The needle is advanced until it contacts the boney edge of the facet joint. The needle is then walked off the bone to slip into the facet joint.

In patients with severe osteoarthritis, the joint space may be narrowed to the point that needle entry is not possible. A periarticular injection can be performed in this situation for therapeutic purposes but a periarticular injection will be of minimal diagnostic value. Following needle entry into the joint, the needle is advanced 2 to 3 mm. Because the lumbar facet joint surfaces are curved, it is often not possible to advance more than 2 to 3 mm. Intra-articular position is confirmed by injecting 0.5 mL of contrast suitable for intrathecal injection (e.g., iopamidol). A typical lumbar facet arthrogram is shown in Figure 67-32.

It is not unusual for the facet capsule to have small fenestrations. It is possible that the injectant may spread to contiguous structures including the epidural space or intervertebral foramen. It is important to identify such spread during the contrast injection, if the injection is being used for diagnostic purposes, as spread to the epidural space or adjacent nerve root would limit the diagnostic utility of the injection. Figure 67-33 is an example of contrast spreading from the L5S1 facet joint to the adjacent S1 nerve root. Arthrography is followed by the diagnostic or therapeutic injection. Typically, 0.25 to 0.50 mL of anesthetic is mixed with 0.25 to 0.50 mL of corticosteroid for each joint.

Complications following facet joint injection are uncommon and include intravascular injection, spinal injection, infection, and needle trauma to the joint or adjacent nerve root.

Costovertebral Joint Injections

The pain related to costovertebral and costotransverse joints usually is unilateral, beginning in a paravertebral location and often radiates in a banklike fashion around the thorax.54,55 The pain is described as aching and burning, and is usually worse in the morning. It is also worsened by deep inspiration, coughing, and twisting or rotation of the torso.

The injection is performed with fluoroscopy guidance to minimize the risk of pneumothorax. The patient is placed in the prone position, and the lateral tip of the transverse process of the level in question is identified. The skin is entered just cephalad and lateral to this point, with a 25-gauge 3½-in. needle directed medially, usually approximately 3 cm from midline. The needle is advanced approximately 3 to 4 cm until contact is made with the vertebral body, which indicates that the needle tip is in the intertransverse space. The needle tip placement is then adjusted cephalad or caudad until it lies within the joint, or pierces the articular capsule. At this point, 0.5 to 1 mL of local anesthetic and/or depot steroid is injected.

Pneumothorax is the most feared complication of this block, although the incidence should be low with proper technique and fluoroscopic guidance.

Costosternal Joint Injection

Costosternal joint pain can be post-traumatic or inflammatory in nature. The costosternal joints are synovial joints; however, the joint space can be obliterated or replaced by fibrous tissue.

The patient is placed supine and the affected joint (or joints) is identified by palpation. Fluoroscopy is not helpful as the costosternal joints are not identifiable with plain x-ray films or fluoroscopy. The joint space is usually identifiable by palpating a groove between the costal cartilage and the sternum. Once identified, the affected joint is injected with 0.5 to 1.0 mL of local anesthetic and/or corticosteroid using a 25-gauge 1-in. needle (see Fig. 67-2).

Sternoclavicular Joint Injection

The patient is placed in the supine position, and the gap between the medial end of the clavicle and the sternum is palpated. The joint is entered with a 25-gauge 1-in. needle and 1 mL of local anesthetic and/or depot steroid is injected (see Fig. 67-2). There should be little resistance to injection. If resistance is encountered, the needle tip is most likely in the meniscal cartilage and should be withdrawn slightly or repositioned until the injectant flows freely.

If posterior sternoclavicular pain is suspected, the posterior ligament of the sternoclavicular joint may be injected. There are two ways to approach this ligament. With the patient in the supine position, a slightly longer 25-gauge needle may be passed completely through the joint, until ligamentous resistance is felt, and then 1 mL of local anesthetic and/or depot steroid is injected around the ligament. The alternate approach is to enter the skin above the superior aspect of the clavicle, and walk the needle off the posterior aspect of the clavicle in a slightly medial direction. Again, the injection is carried out as described above.

With both costosternal and sternoclavicular joint injections, care must be taken to have the needle enter the skin perpendicularly in order to diminish the possibility of pneumothorax. With sternoclavicular joint injections, there is also the possibility of puncture of the subclavian artery or vein with a misplaced needle. Careful attention to technique and use of short (e.g., ½ in.) needles should minimize these complications.