Dual-target Ultrasound Guided Corticosteroid Injection for Shoulder Impingement Syndrome

Subacromial injection is considered one of the best treatments for patients with subacromial impingement syndrome. The subacromial bursa is located between the deltoid muscle and the supraspinatus tendon. It facilitates the gliding of the humeral head through the undersurface of the acromion. If the bursa is thickened, the patient may experience pain when he/she tries to raise the arm. In patients with subacromial impingement due to a thickened subacromial bursa, the physician can precisely inject the medication into the bursa using ultrasound guidance. Use of ultrasound guidance has been proven to yield a better effect of pain relief than the technique using guidance. A previous study found that even using ultrasound guidance to deliver medication, there were still many patients suffering from initial treatment failure or recurrence after the first successful injection. Because the pathophysiological mechanism of subacromial impingement is complexed, the proximal biceps tendon may be involved but is often ignored. Recently, the investigators published a randomized controlled trial comparing the effect of dual-target injection (proximal biceps tendon and subacromial bursa) with the standard subacromial injection in patients with subacromial impingement syndrome, and found that the dual target approach was safe and had a longer effective duration than the standard subacromial injection. In this regard, the investigators will conduct a longitudinal follow-up study to examine the long-term effectiveness of the dual-target corticosteroid injection for subacromial impingement syndrome.