Atlas of Primary Care Procedures, 1st Edition

Musculoskeletal Procedures

60

Shoulder Injection

The shoulder comprises a series of joints and musculoskeletal tissues that affords the extraordinary range of motion to the arm. Specific injections have been advocated for a variety of shoulder ailments, but primary care physicians may not have the opportunity or desire to perform some of the less common and more difficult techniques. For instance, injection into the acromioclavicular joint can relieve symptoms of degenerative arthritis, but the opportunity to perform the injection is infrequently encountered in a generalist practice. The glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic joints can be difficult to enter and may be best injected by experienced physicians.

This chapter describes aspiration and injection techniques in the lateral rotator cuff and subacromial bursa. Commonly called a shoulder injection, this procedure generally does not involve entering the shoulder joint. Shoulder injections are easy to perform and frequently provide beneficial intervention for a number of shoulder conditions. Four of the more common shoulder disorders that benefit from this aspiration and injection technique include calcific tendinitis, impingement syndrome, supraspinatus tendonitis, and subacromial bursitis. Anatomic proximity of the rotator cuff tendons and the bursa creates overlap among these conditions, allowing for a similar injection technique for three conditions.

CALCIFIC TENDINITIS

Calcific tendinitis is a degenerative condition of the tendons of the rotator cuff. The supraspinatus tendon is most commonly involved, with localized deposits of calcium identified in the tendon sheath. It is estimated that 2% to 3% of the U.S. adult population suffers from this disorder, although many with the disorder are asymptomatic. The disorder is more common in middle-aged men in the dominant shoulder, and it may be connected to use and activity. More than 25% of individuals have bilateral shoulder involvement. Calcific tendonitis usually is characterized by an acute onset of intense shoulder pain that is not related to position or activity.

Because the subacromial bursa is adjacent to the supraspinatus tendon, most of the pain from calcific tendinitis is related to bursal inflammation. Point tenderness

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is identified over the lateral shoulder, and pain can be produced with active abduction from 60 to 120 degrees. Calcium can be detected on x-ray films (in external rotation); acute deposits are sharply delineated, whereas chronic calcium deposits are hazy and ill defined as they are being resorbed. Symptoms tend to resolve over a period of 2 weeks. Greater degrees of inflammation (i.e., greater pain) tend to result in rupture of the calcium deposit into the overlying bursa, with more rapid resolution of symptoms. Persistently large deposits may lead to disuse and eventually to frozen shoulder.

Acutely painful deposits are treated with injection of a local anesthetic and steroid. Repeated injection of steroid can inhibit repair, and some physicians recommend caution after two injections. Aspiration of calcium-containing (toothpaste-like) tendon fluid has been recommended by some physicians. Removal of calcium requires larger (and more uncomfortable) needles, and the technique can be difficult for patients and practitioners. Some physicians believe that the greatest benefit from injection comes from the needle puncture holes made in the diseased tendon sheath. The holes allow calcium and thick inflammatory fluid to flow into the adjacent bursa, hastening resolution of the tendinitis. The technique that allows for redirecting the needle or fan-shaped application of steroid is likely to produce multiple holes in the sheath.

IMPINGEMENT SYNDROME

Impingement syndrome describes mechanical compression of the rotator cuff between the humeral head and the overlying acromion. Narrowing in this region is often attributed to spur formation on the anteroinferior acromion and may be related to excessive overhead use of the limb in certain sports and occupations. Unlike calcific tendinitis, the major component of discomfort is tendonitis. Three stages of impingement have been described: stage 1, edema and hemorrhage; stage 2, tendinitis and fibrosis; and stage 3, tendon rupture and bony changes.

Patients with impingement commonly complain early of chronic aching in the shoulder. Acute onset of symptoms is much more suggestive of calcific tendinitis. The discomfort of impingement is frequently experienced at night when reaching over the head to grasp the pillow and when abducting the shoulder between 60 and 120 degrees. A positive impingement sign indicates pain just distal to the anterior acromion when passively elevating the arm 30 degrees forward of the coronal plane of the body, with the elbow bent to 90 degrees and the shoulder internally rotated.

Impingement syndrome generally is treated with exercises to restore flexibility and strength. Avoidance of painful activities is important early in the course of this disorder, and nonsteroidal antiinflammatory drugs (NSAIDs) and ice therapy can be added to rest and physical therapy. Steroid injection may provide symptom relief. Surgical procedures are advocated for stage 3 disease.

SUPRASPINATUS TENDINITIS AND SUBACROMIAL BURSITIS

Supraspinatus tendinitis and subacromial bursitis are considered together, because they usually coexist in these adjacent structures. Many physicians believe that these disorders almost always occur as part of the two previously discussed conditions. Primary bursitis in the absence of tendonitis probably is rare, but not all

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tendonitis need be calcific. If calcium cannot be identified on x-ray films or after insertion of the needle tip into the tendon sheath, noncalcific tendinitis is possible.

The point of the shoulder (just under the acromion) is the location of maximal tenderness from supraspinatus tendinitis. Soft tissue disorders of the shoulder are difficult to differentiate clinically, because these conditions produce remarkably similar signs and symptoms. Injection therapy often is a valuable adjunct, unless there is evidence of complete rotator cuff tear or loss of motor function.

RELATIVE CONTRAINDICATIONS

• Uncooperative patient
• Bleeding diathesis or coagulopathym
• Bacteremia or cellulitis overlying the lateral shoulder
• Evidence of complete rotator cuff tear

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PROCEDURE

Anatomy of the shoulder is illustrated.

The subacromial bursa lies between the deltoid muscle and the supraspinatus muscle.

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Circumscribed, distinct margins of the calcium deposit in the supraspinatus tendon suggests an acute process.

The examiner stands behind the seated patient. The patient's elbow is flexed to 90 degrees, and the shoulder is internally rotated so that the patient's hand lies over the trunk. The arm is elevated and abducted to about 30 degrees anterior (slightly forward) of the coronal plane of the body. A positive impingement sign is accentuation of the pain with this technique and tenderness just below the acromion.

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One technique for locating the point of maximal tenderness uses the palpation of multiple sites with the index finger, asking the patient to differentiate between sites 1 and 2. This is repeated until the site is identified, and the skin is marked by indentation with a fingernail or capped needle.

After skin preparation, a 22- to 25-gauge needle is inserted horizontally under the acromion until the supraspinatus tendon is reached. If calcium exists in the tendon sheath, it often creates a gritty feel on the needle tip.

Between 4 and 8 mL of 1% lidocaine is added to the steroid in the syringe, as administering the added volume of fluid appears to improve symptom resolution. The added volume also facilitates a fan-shaped administration of the solution. Multiple punctures can be made in the tendon sheath, and administration of solution is made around the tendon and in several sites in the bursa. A bandage is applied to the skin after removal of the needle.

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CODING INFORMATION

INSTRUMENT AND MATERIALS ORDERING

Consult the ordering information in Chapter 65. A suggested tray for performing soft tissue aspirations and injections is listed in Appendix D. Skin preparation recommendations appear in Appendix H.

BIBLIOGRAPHY

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