风湿性疾病的肌肉骨骼超声七

Chapter 7 Ultrasound-guided procedures 205 Needle aspiration of synovial fluid and intra- lesional injection of various compounds are very common procedures in rheumatological practice. Local steroid injection, in particular, is relatively simple and cost-effective and may be alternative or adjunctive to systemic drug therapy in several rheumatological conditions [1-5]. Both efficacy and side effects of the injection depend on the correct placement of the tip of the needle inside or around the lesion. Particular attention must be taken to avoid direct needle contact with nerves, tendons, articular cartilage and blood vessels [6]. Intra-articular and intra-lesional therapy is usu- ally performed using palpation and bony land- marks for guidance. Conventional blind inter- ventional procedures may be particularly prob- lematic when a small and/or deep target has to be reached, or when an injection has to be carried out into a dry joint. It has been reported that 50% of conventional joint injections are placed incorrectly [7-8]. US guidance during such procedures may min- imize both the difficulty and margin for error dur- ing intra-lesional therapy. This approach is, how- ever, still very limited in rheumatological practice. US-guided injections can be performed using the method where the skin surface is marked after the detection of the most appropriate entrance point and the measurement of the depth of the target area, or under direct visualization of needle place- ment during real-time scanning [1, 2]. US-guided injection under direct visualization should be performed according to the following principles: 1. Baseline US assessment to explore the target area and evaluate the indication for the planned injection therapy. 2. Definition of the best US window to optimize visualization of needle placement within the target area. 3. Antiseptic swabbing of both the injection site and the surface of the probe. 4. Placement of a thin layer of sterile gel on the skin of the patient. 5. Continuous monitoring of the needle progres- sion within the soft tissues on the screen with particular attention to the tip of the needle, which is placed within the target area. 6. Visualization of the steroid suspension during and after the injection (Fig. 7.1). Rheumatoid arthritis.US-guided injection of triamcinolone acetonide (5 mg) into a metacarpophalangeal joint with proliferative synovitis.a Placement of the tip of the needle (arrowhead) in the target area.b Visualization of the steroid suspension (d) during the injection. m = metacarpal head; * = synovial fluid; + = synovial proliferation Fig. 7.1 a, b a b 206 Musculoskeletal Sonography On longitudinal scans, when the needle is per- pendicular to the US beam it appears as a sharply defined echoic band with strong posterior rever- berations. On transverse scan, the needle appears as a small hyperechoic round spot that can be easily identified by dynamic assessment (fine movements of the syringe). Confirmation of the needle’s correct position- ing can be obtained by direct observation by inject- ing air or under power Doppler control (the inject- ed fluid is visualized as a patch of color). Needle placement is quick and easy to perform when marked distension of the joint cavity is pres- ent. Optimal visualization of the needle depends on the correct alignment between the needle and ultrasound beam.Accurate positioning of the probe is critical to obtain a clearly defined image both of the needle and the target site (Fig. 7.2). Local injection therapy has a well-established role in patients with tenosynovitis. The cost/benefit ratio largely depends on the cor- rect placement of the needle into the widened ten- don sheath.An experienced rheumatologist should be able to perform a safe and accurate intra-lesion- al injection in most patients with tenosynovitis. The main problem is taking care to avoid contact between the tip of the needle and the tendon (Fig. 7.3). The conventional blind approach to intra-lesion- al injection cannot avoid the theoretical risk of caus- ing damage to tendons and surrounding structures. Joint effusion in knee osteoarthri- tis. US-guided aspiration using a supra-patellar transverse scan with the knee extended. a, b Different steps during synovial fluid (*) aspi- ration. The arrowhead indicates the tip of the needle. f = femur; t = quadriceps tendon Fig. 7.2 a, b a b Carpal tunnel syndrome due to rheumatoid tenosynovitis of the finger flexor tendons. Position of the tip of the needle is accu- rately visualized both on transverse (a) and longitudinal (b) scans.arrowhead = tip of the needle; f = finger flexor tendons;n = medi- an nerve; t = flexor carpi radialis tendon Fig. 7.3 a, b a b Ultrasound-guided procedures 207Chapter 7 The injection of steroids within a widened tendon sheath under US control appears to be very effective in minimizing this risk. The progression of the nee- dle can be accurately controlled “step by step” on the monitor until the tip of the needle is properly placed within the tendon sheath. Bursitis is a very common problem in rheuma- tological practice. Injection of steroid is an effec- tive and safe procedure in non-responders to other conservative therapeutic options, including rest, local application of ice and anti-inflammatory medication. The US approach to patients with sus- pected bursitis serves three purposes: firstly, con- firmation of the diagnosis; secondly, aspiration of synovial fluid for microscopic examination and thirdly, correct placement of the needle for steroid injection. US is very useful for the detection of popliteal cysts and for careful assessment of their content. Once the inner structure of the cyst is established, it is possible to define an appropriate therapeutic approach that depends on the cyst characteristics. Needle aspiration of synovial fluid and steroid injection within a popliteal cyst under US control are indicated especially in patients with large cysts due to a valve effect of the synovial tissue. US con- trol is critical to avoid puncture wounds of nerves and/or blood vessels and to ensure the correct posi- tion of the tip of the needle especially in patients with loculated cysts. References 1. Koski JM (2000) Ultrasound guided injections in rheu- matology. J Rheumatol 27:2131-2138 2. Grassi W, Farina A, Filippucci E, Cervini C (2001) Sono- graphically guided procedures in rheumatology. Semin Arthritis Rheum 30:347-353 3. Grassi W, Farina A, Filippucci E, Cervini C (2002) Intra- lesional therapy in carpal tunnel syndrome: a sono- graphic-guided approach. Clin Exp Reumatol 20:73-76 4. Qvistgaard E, Kristoffersen H, Terslev L et al (2001) Guidance by ultrasound of intra-articular injections in the knee and hip joints. Osteoarthritis Cartilage 9:512-517 5. Balint PV, Kane D, Sturrock RD (2001) Modern patient management in rheumatology: interventional muscu- loskeletal ultrasonography. Osteoarthritis Cartilage 9:509-511 6. Kumar N, Newmon RJ (1999) Complications of intra- and peri-articular steroid injections. Br J Gen Pract 49:465-466 7. Jones A, Regan M, Ledingham J et al (1993) Importan- ce of placement of intra-articular steroid injections. Br Med J 307:1329-1330 8. Eustace JA, Brophy DP, Gibney RP et al (1997) Compa- rison of the accuracy of steroid placement with clini- cal outcome in patients with shoulder symptoms. Ann Rheum Dis 56:59-63