In a randomized trial, lateral and anterior routes were better than posterior.

The subacromial bursa can be injected using anterior, lateral, or posterior approaches. To determine which approach is best, U.S. researchers performed a study in which each of 75 patients with rotator cuff syndrome was randomized to one of these three approaches. A single orthopedist (who traditionally had used the posterior approach) performed all injections, which contained corticosteroid, local anesthetic, and radiopaque contrast medium. After the injections, shoulders were x-rayed to determine whether the contrast was within the bursa.

The proportion of patients whose injections were intrabursal was significantly greater with the lateral and anterior approaches (92% and 84%, respectively) than with the posterior approach (56%). The lower accuracy of the posterior approach was especially striking in women. Pain relief at 1 hour was significantly greater in patients whose injections were intrabursal than in those whose injections were extrabursal.

Comment: A limitation of this study is that a single physician did the injections; nevertheless, the authors discuss anatomic reasons why the posterior route might be the least accurate. I’ve always done subacromial injections via the lateral approach; this study vindicates that practice.

Source: Journal Watch General Medicine