PM R 7 (2015) 329-333
www.pmrjournal.org
Case Presentation
Ultrasonography of Subcoracoid Bursal Impingement Syndrome Shane Drakes, MD, Sunil Thomas, MD, Sooyeon Kim, MD, Luis Guerrero, MD, Se Won Lee, MD
Abstract Subcoracoid impingement syndrome with bursitis is an underrecognized cause of anterior shoulder pain. It usually presents with pain around the coracoid process and a positive impingement test with shoulder adduction, forward flexion, and internal rotation. The pain is mediated by impingement of soft tissues such as the subcoracoid bursa or subscapularis tendon between the coracoid process and humerus. Ultrasonography (US) can be useful in the evaluation of subcoracoid bursal impingement syndrome because of its high resolution capacity and the use of dynamic maneuvers. In this case series, we present 3 patients with subcoracoid impingement syndrome with bursitis diagnosed with in-office US. This case series illustrates the application of US in the evaluation of anterior shoulder pain with subcoracoid bursal impingement syndrome.
Shoulder impingement syndrome is 1 of the most common causes of shoulder pain [1]. It is caused by entrapment of the soft tissues such as rotator cuff, biceps tendon, bursa and the capsule of the glenohumeral joint between the humeral head, labrum, and the coracoacromial arch including the coracoid process, coracoacromial ligament, and acromioclavicular joint complex [2]. Depending on the location of entrapment, it can be categorized into subacromial, postero-superior, and subcoracoid impingement, with subacromial impingement syndrome being the most common. Subcoracoid impingement is an underrecognized cause of anterior shoulder pain. It involves the rotator cuff tendons (most commonly the subscapularis tendon), the glenohumeral joint capsule, and the subcoracoid bursa specifically between the coracoid process and the humeral head. The subcoracoid bursa is located between the coracoid process, the conjoint tendon (of the biceps short head and coracobrachialis) and the subscapularis, and minimizes the friction between the coracoid and the subscapularis. The subcoracoid bursa occasionally communicates with the subacromial bursa [3] and merges with the superior subscapularis recess known as subscapularis bursa (under the subscapularis) [4]. Subcoracoid impingement syndrome is usually diagnosed clinically with anterior shoulder pain with positive provocative tests and possibly with a diagnostic injection.
Imaging studies are helpful in evaluating the anatomical structures located in the anterior shoulder region, including the subscapularis muscle/tendon, biceps tendon/ tenosynovium, subcoracoid bursa, and glenohumeral joint complex [5]. Ultrasonography (US) is an effective modality to evaluate these anatomic structures, and the ability to perform a dynamic evaluation can be useful to assess snapping and to aid in narrowing the differential diagnosis of anterior shoulder pain. Herein, we present 3 patients with complaints of anterior shoulder pain with impingement signs who were subsequently diagnosed with subcoracoid impingement syndrome with bursitis using dynamic US. Case Presentation Patient 1 A 44-year-old, left handedominant woman presented with right shoulder pain that had been present for years. She had previously received a noneimage-guided subacromial injection, with relief for a few days. The pain was rated as 7 out of 10 on the numeric pain scale and was located at the anterior aspect of the shoulder with a “snapping-like sensation.” It started without any preceding injury or trauma and was aggravated by overhead activity. Physical examination was positive in
1934-1482/$ - see front matter ª 2015 by the American Academy of Physical Medicine and Rehabilitation http://dx.doi.org/10.1016/j.pmrj.2014.09.015
330
US of Subcoracoid Bursal Impingement Syndrome
Neer’s, Speed’s, Hawkins’, and coracoid impingement (a position of cross arm adduction, forward elevation, and internal rotation) tests. An x ray of the shoulder was unremarkable. Ultrasound evaluation of the right shoulder was performed with LOGIQ S8 scanner with an 8- to 15-Hz broadband linear transducer (GE Healthcare, Milwaukee, WI). Significant bursal thickening in the subcoracoid region was noted, as well as snapping under the coracoid process during dynamic evaluation (internal and external rotation) (Figure 1). Biceps tendon/ tenosynovium was within normal limits. No gross tendon thickening, calcification, or tear was noted in the subscapularis or supraspinatus tendons. No significant joint effusion was observed in the acromioclavicular joint or posterior glenohumeral joint. The patient underwent US-guided steroid injection to the subcoracoid bursa and had significant pain relief for more than 3 months. Patient 2 A 49-year-old right handedominant woman with a past medical history of hypothyroidism presented with left anterior shoulder pain for a few months, of gradual onset. The pain was rated as 5 out of 10 and was located in the anterior aspect of the shoulder. It was accompanied by a “snapping-like sensation” in the anterior aspect of the shoulder. The patient underwent a noneimage guided subacromial steroid injection with only temporary pain relief and persistent snapping of the shoulder. The patient was referred for musculoskeletal ultrasonography (US) evaluation. Physical
examination revealed tenderness at the coracoid process and a positive Speed’s test. A US evaluation of rotator cuff tendons and long head of the biceps was normal. No capsular bulging or significant separation was noted in the acromioclavicular joint evaluation. Dynamic US examination, including internal and external rotation of the glenohumeral joint, revealed subcoracoid bursal thickening causing snapping under the coracoid process (Figure 2). Snapping was palpated under the US probe with glenohumeral internal/external rotation. MRI of the shoulder did not reveal other bony or labral pathology to explain the shoulder snapping. Patient 3 A 74-year-old right handedominant female woman presented with left shoulder pain that started gradually after open heart surgery for a triple coronary artery bypass. The pain was described as aching and located in the anterior shoulder, with occasional radiation to the lateral aspect of the forearm. The pain gradually worsened to 8 to 9 out of 10 and was aggravated by overhead movements. Physical examination revealed positive Hawkins’, Neer’s, and coracoid impingement tests. Electrodiagnostic evaluation ruled out brachial plexopathy and cervical radiculopathy. Sensory nerve conduction study was normal in the lateral antebrachial cutaneous and radial/median nerves to digits I to III. Needle electromyographic examination of the left biceps, brachialis, deltoid, infraspinatus, and cervical parspinal muscles was within normal limits. US evaluation
Figure 1. Ultrasound imaging of the subcoracoid bursal impingement syndrome. Long-axis view of the isoechoic heterogeneous thickened subcoracoid subdeltoid bursa superficial to the subscapularis tendon on external rotation of the shoulder (A). On oblique sagittal view, hypoechoic bursal effusion is noted under the conjoint tendon (biceps short head and coracobrachialis) attached to the coracoid process (B). Long-axis (C) and short-axis (D) view of the supraspinatus tendon.
S. Drakes et al. / PM R 7 (2015) 329-333
331
Figure 2. Transverse ultrasound imaging of the anterior shoulder. On external rotation of the shoulder (A), isoechoic heterogeneous thickened subcoracoid subdeltoid bursa superficial to the subscapularis tendon is noted under the coracoid process with palpable snapping compared to internal rotation of the shoulder (B).
of the shoulder revealed an anechoic effusion immediately adjacent to the coracoid process above the subscapularis tendon on transverse view with external rotation of the shoulder. On the oblique sagittal view, a significant bursal effusion was observed surrounding the conjoint tendon and under the coracoid process (Figure 3). Magnetic resonance imaging (MRI) of the shoulder was performed to evaluate other periarticular structures and verified the US findings (Figure 3). The patient received a US-guided steroid injection that provided approximately 70% pain relief and resolution of radiating pain for more than 1 year despite a persistent effusion. Discussion This case series illustrates the US findings of subcoracoid impingement syndrome with bursitis
presenting with anterior shoulder pain with shoulder impingement signs and anterior shoulder snapping and radiating pain to the forearm. MRI has been used as a gold-standard test for evaluation of musculoskeletal pathology because of its ability to evaluate multiple structures including bony lesions (edema/subtle fracture), cartilage, and capsular and ligamentous abnormalities. In addition, MRI has less dependence on operator skill when compared to US. However, the cost and accessibility of MRI have been significant barriers to routine use [6]. Interestingly, MRI evaluation failed to reveal any pathological finding explaining the symptoms in patient 2 compared to dynamic US evaluation, which illustrates a relative advantage of US over static MRI. Ultrasound has been used in subacromial impingement syndrome as a guide for subacromial injections as well as demonstrating increased
Figure 3. Transverse ultrasound view (A) of subcoracoid bursitis with effusion between the coracoid process and subscapularis tendon. Longitudinal view (B) of conjoined tendon attached to the coracoid process demonstrate the subcoracoid bursal effusion under the coracoid process and surrounding conjoined tendon. Fat suppressed axial (3-C) and sagittal (3-D) MRI images demonstrate distension of subcoracoid bursa with effusion.
332
US of Subcoracoid Bursal Impingement Syndrome
bursal thickness [7]. Although dynamic US examinations have previously shown the different stages of subacromial impingement [8], the use of dynamic US in diagnosing subcoracoid impingement syndrome was only recently demonstrated in a patient with anterior snapping syndrome [5]. All 3 patients presented with anterior shoulder pain that was aggravated by overhead activity, similar to subacromial impingement syndrome. Although clinically it can be difficult to differentiate subcoracoid impingement from subacromial impingement, certain findings can be ascertained from the history and physical examination that can aid in diagnosis, as highlighted by this case series. Historically, the location of typical pain in the anterior shoulder in the vicinity of the coracoid process may favor subcoracoid syndrome versus the anterolateral or lateral aspect of the shoulder in subacromial impingement syndrome [9]. Physical examination findings of anterior pain or reproduction of the symptoms with adduction of the arm is reported to be more specific for subcoracoid syndrome [10]. The theoretical mechanism is impingement of the soft tissues between the coracoid process and the lesser tuberosity [11,12]. Patients with subcoracoid impingement syndrome have been described to also have intermittent pain to the forearm, as in patient 3 [13]. With the proximity of the musculocutaneous nerve to the coracoid process, the radiating pain may be attributed to nerve irritation; however, this was not confirmed by nerve conduction studies and needle EMG in patient 3. Snapping syndrome can be caused by impingement of soft tissue on bony structures or soft tissues on other soft tissues, which is perceived by patients along a spectrum ranging from mild discomfort to significant pain [14]. Dynamic US can facilitate identification of the source of “snapping” pain to a greater extent than can MRI alone. The differential diagnosis for anterior shoulder snapping includes biceps tendon instability, labral tears, chondral or osteochondral lesions, bursopathy and tendinopathy, glenohumeral instability, and intraarticular loose bodies [5]. Etiologies of subcoracoid impingement syndrome are multifactorial including idiopathic, traumatic, iatrogenic, and secondary causes. The shape of the coracoid process is considered to be a predisposing factor by decreasing the coracoglenoid angle and coracoid overlap, similar to the acromion shape in subacromial impingement syndrome [11]. The normal coracohumeral interval, defined as minimal distance between the coracoid process and lesser tuberosity, is in the range of 8.4 to 11 mm. Subcoracoid stenosis is defined as a decreased coracohumeral interval less than 6 mm and can contribute to subcoracoid impingement syndrome [11]. The impingement resulting from the subcoracoid stenosis can lead to subscapularis tears by repeated tensile loading (stretching) of the undersurface of the
subscapularis tendon. Glenohumeral internal rotation with the arm in adduction causes the coracoid process to roll toward the insertion of the subscapularis tendon. Although the coracoid process impinges upon the superficial surface of the subscapularis tendon, it applies a tensile load (stretching) to the deep surface or undersurface of the tendon, the “roller wringer effect” resulting in tensile undersurface fiber failure [11]. However, subcoracoid bursal thickening or significant effusion, as depicted in this case series, can decrease subcoracoid space/coracohumeral interval relatively without absolute decrease in coracohumeral interval or subcoracoid stenosis. In addition, the subcoracoid bursa, which occasionally blends with the subscapularis bursa (in 28% of a previous cadaveric study) minimizes the friction of the superficial fibers of the subscapularis against the coracoid bursa [4]. Therefore, the bursitis can contribute to the subcoracoid impingement syndrome. Other pathologic conditions of soft tissue or bony structures, such as calcification of subscapularis tendon, ganglion cyst, and superior migration of the humeral head can also cause subcoracoid impingement syndrome [9,15]. Superior migration of the humeral head can be due to either a massive rotator cuff tear or minor anterior shoulder instability caused by insufficiency of the middle and inferior glenohumeral ligaments [13]. Similar to subacromial impingement, the nonsurgical treatment of subcoracoid impingement emphasizes proper scapular biomechanics via a graduated exercise and return-to-activity program. Asymmetric scapular protraction and less anterior tilting of the scapula has been shown to be associated with shoulder impingement syndrome [16,17]. Therefore, scapular stabilization (including stretching of the scapular protractors and strengthening of scapular retractors), and stretching of the subscapularis and strengthening of other rotator cuff muscles and biceps muscle, should be initiated and progressed to allow for restoration of the coracohumeral interval [18]. Injection of local anesthetic and corticosteroid into the subcoracoid area also has proved to be useful for relieving pain. US can be useful to guide the needle, as illustrated in this case series. Surgery is reserved for refractory pain with or without snapping. The surgical approach is to fix the underlying structural cause of impingement. Similar to acromioplasty for subacromial impingement, nonspecific surgery for subcoracoid impingement or coracoplasty does not provide long-term benefit. Conclusion These cases illustrate the increasing utility of inoffice US in the management of patients with anterior shoulder pain. Subcoracoid impingement syndrome with bursitis should be included in the differential diagnosis, and dynamic US maneuvers should be considered.
S. Drakes et al. / PM R 7 (2015) 329-333
Video Gallery: To view the online video, use your smartphone camera QR Reader App to scan and capture this QR Code, text GS3D18 to 64842, or visit www.pmrjournal.org to locate this video content. URL: http://www.pmrjournal.org/article/ S1934-1482(14)01413-0/fulltext
References 1. Morrison DS, Greenbaum BS, Einhorn A. Shoulder impingement. Orthop Clin North Am 2000;31:285-293. 2. Rossi F. Shoulder impingement syndromes. Eur J Radiol 1998; 27(Suppl 1):S42-S48. 3. Grainger AJ, et al. MR anatomy of the subcoracoid bursa and the association of subcoracoid effusion with tears of the anterior rotator cuff and the rotator interval. AJR Am J Roentgenol 2000; 174:1377-1380. 4. Colas F, Nevoux J, Gagey O. The subscapular and subcoracoid bursae: Descriptive and functional anatomy. J Shoulder Elbow Surg 2004;13:454-458. 5. Finnoff JT, Thompson JM, Collins M, Dahm D. Subcoracoid bursitis as an unusual cause of painful anterior shoulder snapping in a weight lifter. Am J Sports Med 2010;38:1687-1692. 6. Babyn P, Doria AS. Radiologic investigation of rheumatic diseases. Rheum Dis Clin North Am 2007;33:403-440. 7. Tsai YH, Huang TJ, Hsu WH, et al. Detection of subacromial bursa thickening by sonography in shoulder impingement syndrome. Chang Gung Med J 2007;30:135-141.
333
8. Bureau NJ, Beauchamp M, Cardinal E, Brassard P. Dynamic sonography evaluation of shoulder impingement syndrome. AJR Am J Roentgenol 2006;187:216-220. 9. Gerber C, Terrier F, Ganz R. The role of the coracoid process in the chronic impingement syndrome. J Bone Joint Surg Br 1985;67: 703-708. 10. Dines DM, Warren RF, Inglis AE, Pavlov H. The coracoid impingement syndrome. J Bone Joint Surg Br 1990;72:314-316. 11. Lo IK, Burkhart SS. The etiology and assessment of subscapularis tendon tears: A case for subcoracoid impingement, the rollerwringer effect, and TUFF lesions of the subscapularis. Arthroscopy 2003;19:1142-1150. 12. Beltran LS, Nikac V, Beltran J. Internal impingement syndromes. Magn Reson Imaging Clin North Am 2012;20:201-211, ix-x. 13. Garofalo R, Conti M, Massazza G, Cesari E, Vinci E, Castagna A. Subcoracoid impingement syndrome: A painful shoulder condition related to different pathologic factors. Musculoskelet Surg 2011; 95(Suppl 1):S25-S29. 14. Blankenbaker DG, De Smet AA, Keene JS. Sonography of the iliopsoas tendon and injection of the iliopsoas bursa for diagnosis and management of the painful snapping hip. Skelet Radiol 2006;35:565-571. 15. Ko JY, Shih CH, Chen WJ, Yamamoto R. Coracoid impingement caused by a ganglion from the subscapularis tendon. A case report. J Bone Joint Surg Am 1994;76:1709-1711. 16. Hebert LJ, Moffet H, McFadyen BJ, Dionne CE. Scapular behavior in shoulder impingement syndrome. Arch Phys Med Rehabil 2002;83: 60-69. 17. Kibler WB, Sciascia A. Current concepts: Scapular dyskinesis. Br J Sports Med 2010;44:300-305. 18. Roche SJ, Kennedy MT, Butt AJ, Kaar K. Coracoid impingement syndrome: A treatable cause of anterior shoulder pain. Ir J Med Sci 2006;175:57-61.
Disclosure S.D. Department of Physical Medicine and Rehabilitation, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY Disclosure: nothing to disclose
L.G. Department of Physical Medicine and Rehabilitation, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY Disclosure: nothing to disclose
S.T. Department of Physical Medicine and Rehabilitation, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY Disclosure: nothing to disclose
S.L. Department of Physical Medicine and Rehabilitation, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY. Address correspondence to: S.W.L.; e-mail:
[email protected] Disclosure: nothing to disclose
S.K. Department of Physical Medicine and Rehabilitation, Montefiore Medical Center, Albert Einstein College of Medicine, 110 East 210th Street, Bronx, NY 10467 Disclosure: nothing to disclose
Submitted for publication March 31, 2014; accepted September 23, 2014.
