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Article Excerpt
ABSTRACT: Corticosteroid/anesthetic injections may be useful diagnostic and therapeutic tools for painful shoulder conditions. The current dogma is to avoid performing more than 3 injections over a 9- to 12-month period, but this rule may be broken. The volume of local anesthetic typically injected might be insufficient for assessing accuracy. Data demonstrating significant advantages of one corticosteroid over another are scarce. For patients with diabetes mellitus, consider a somewhat insoluble phosphoric corticosteroid. There is no consensus about appropriate dosages and techniques. We recommend using 1.5-inch 25-gauge needles for most injections. Re-evaluating provocative maneuvers after each injection is important. The patient's estimated pain relief always should be documented. Two approaches to injection may be used, an advanced/detailed method and a basic/quick method. (J Musculoskel Med. 2008;25:375-386)
Corticosteroid/anesthetic injections may be useful diagnostic and therapeutic tools for physicians treating patients with painful shoulder conditions. When clinicians have a clear understanding of the local and systemic effects, indications, contraindications, appropriate doses and dose ranges, and methods for injecting corticosteroid/ anesthetic mixtures, they may administer these injections safely and effectively.
This 3-part article describes the diagnostic and therapeutic uses of corticosteroid/anesthetic injections for painful shoulder conditions. The first part ("The use and misuse of injectable corticosteroids for the painful shoulder," The Journal of Musculoskeletal Medicine, February 2008, page 78) covered the mechanism of action, current preparations, indications and contraindications, adverse effects, misuses, and lack of uniform standards of care. In the second part ("Injectable corticosteroids for the painful shoulder: Patient evaluation," The Journal of Musculoskeletal Medicine, May 2008, page 236), we discussed physical examination and radiographic evaluation procedures for determining when to inject corticosteroids. This third part describes specific injection techniques and approaches and offers algorithms for evaluation and injection.
FREQUENCY, DOSE, TYPE, AND LOCATIONS
The current dogma in corticosteroid injection for most shoulder conditions is to avoid performing more than 3 injections over a 9- to 12-month period. However, this rule may be broken.
We often "reset" the injection count when pain recurs after a 12-month injection-free and, typically, pain-free interval. If there is significant pain during the 12 months, however, starting a "new" series of corticosteroid injections may not be appropriate. For example, recurrent pain localized to the subacromial (SA) area may require a different treatment strategy, including re-examination with additional diagnostic imaging (eg, MRI), giving only 1 more injection (maybe only local anesthetic for diagnostic purposes), and resumption of physical therapy.
Can and should injections be given when there is a rotator cuff tear? They may be useful in treating middle-aged to older patients who have acute or subacute cuff tears that are potentially operative. In fact, animal studies support the idea that delaying surgery while nonoperative measures are attempted does not necessarily compromise a good surgical outcome. (1)
By decreasing inflammation resulting from the SA bursitis that accompanies a rotator cuff tear, corticosteroid injections may provide short-term pain relief. In some cases, physical therapy could then be started. In a few patients, the relief is at an acceptable level and surgery may be avoided; in these cases, especially when the tear is posttraumatic, we try to make a definitive decision about whether to perform surgery within 2 to 3 months of injury. In addition, corticosteroids should be used judiciously because they may weaken tendons.
In contrast, when a chronic tear is present and is considered nonoperative and where replacement arthroplasty is not an option, we allow 2 or 3 injections per year. Again, this usually is done in older patients (eg, older than 70 years) who want to avoid surgery. In some of these cases, the diagnosis is rotator cuff tear arthropathy.
Injection volumes/doses
In many cases, the volume of local anesthetic typically injected with corticosteroid into some regions of the shoulder might be insufficient for assessing injection accuracy. For example, in 1983, Neer (2) described the SA impingement "test" as injecting 10 cc of 1.0% lidocaine into the SA bursa. This test is based on comparison of pain elicited from the impingement sign preinjection with pain elicited 10 minutes postinjection. It also may be used to help determine whether the cause of limited range of motion is shoulder pain or weakness attributed to a rotator cuff tear. (3)
Neer (4) found that these techniques were "the most valuable method for separating impingement lesions from other causes of chronic shoulder pain." The impingement test also has been used to predict surgical outcomes. (5-8) Therefore, we use similarly "large" volumes of anesthetic in our diagnostic/ therapeutic injections.
Using large volumes of corticosteroid/ anesthetic solution and injecting in the posterior third, middle, and anterior third of the SA space may help prevent the solution from being localized into "compartments" that might occur normally or be associated...
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