Ultrasound Identification of Maximal Subdeltoid Bursa Distention Alters the Ultrasound-Guided Injection Approach for Shoulder Pain

Research Article

Phys Med Rehabil Int. 2015;2(5): 1048.

Ultrasound Identification of Maximal Subdeltoid Bursa Distention Alters the Ultrasound-Guided Injection Approach for Shoulder Pain

Ramey LN1,2, Knowlton SE1,2, Amorese-O’Connell L³ and Kohler MJ2,4*

1Department of Physical Medicine and Rehabilitation,Spaulding Rehabilitation Hospital, USA

2Harvard Medical School, USA

3Division of Rheumatology, Brown University, USA

4Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, USA

*Corresponding author: Kohler MJ, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital, USA

Received: April 09, 2015; Accepted: June 01, 2015; Published: June 03, 2015


Objective: Landmark-guided injections (LMGIs) of corticosteroid (CS) into the subdeltoid bursa (SDB) are typically provided from a posterolateral approach, aiming at the subacromial aspect of the bursa with varying accuracy and response. Ultrasound (US) can visualize bursal abnormalities and is known to improve injection accuracy. Our objective was to evaluate how US affects the injection approach used for treatment of subacromial impingement.

Methods: We reviewed clinical and US characteristics of 67 patients with impingement syndrome who received 96 SDB US-guided injections (USGIs) in one rheumatology US clinic. Images were obtained and interpreted by 1 musculoskeletal ultrasound (MSUS) trained rheumatologist and reviewed by 2 MSUS trained physiatrists.

Results: Patients were mostly female (62.7%) with a mean age of 63.5±14.7 years and BMI of 28.8±7.02. Twenty-six (38.8%) received prior LMGIs with more than half (61.5%) reporting little to no benefit. USGI approach was determined by localizing the area of maximal SBD thickening and distension on US. USGIs were targeted subacromially in only 40.6% of cases; 59.4% were targeted anterior to the acromion: 37.5% anterior over the subscapularis tendon, 19.8% anterolateral over the supraspinatus tendon, and 2.0% anterior over the biceps tendon. Nearly all patients reported significant improvement immediately post-procedure.

Conclusion: Point-of-care US identified SDB abnormality to occur more frequently anterior to the acromion, rather than below it. This may contribute to LMGI failure, as LMGIs are typically directed at the posterior border of the bursa beneath the acromion. This method has the potential to improve clinical outcomes. Future prospective studies are needed.

Keywords: Subacromial impingement; Subdeltoid bursitis; Ultrasound; Ultrasound-guided injection; Corticosteroid injection


SDB: Sub Deltoid Bursa; CS: Corticosteroid; LMGI: Landmarkguided Injection; US: Ultrasound; USGI: Ultrasound-guided Injection; MSUS: Musculoskeletal Ultrasound; AMSSM: American Medical Society of Sports Medicine; BMI: Body Mass Index


Shoulder pain is a common musculoskeletal complaint seen in sports, orthopedic, rheumatology, and primary care clinics. Subacromial impingement syndrome, defined as subdeltoid bursitis and/or rotator cuff tendinitis, is a common cause of shoulder pain [1-3]. Symptoms are thought to occur because of impingement of the subdeltoid bursa (SDB) and neighboring tendons beneath their rigid overlying structures, including the acromion process, the coracoid process and the coracoacromial ligament, together referred to as the coracoacromial arch.

SDB corticosteroid (CS) injections are widely used to treat shoulder pain due to subacromial impingement unresponsive to more conservative treatments, including analgesics, nonsteroidal anti-inflammatories and physical therapy [4-9]. Injections are traditionally given by palpating known bony landmarks for guidance. These landmark-guided injections (LMGIs) can be given using various approaches. However, based on anecdotal data and technical instructions published in multiple national guidelines, they are traditionally given from a posterolateral approach with medication directed subacromially [7,10]. The American Family Physician guidelines describe a posterolateral approach with needle insertion inferior to the posterolateral edge of the acromion directing the needle toward the opposite nipple [10]. A review by Gruson et al similarly describes the posterolateral approach as being identified 2 cm distal and 1 cm medial to the posterolateral tip of the acromion with the needle angled approximately 45° cephalad [7]. This approach is potentially favored because the bursa is easily accessible from this angle and it provides reproducible, palpable bony landmarks for guidance. Mathews and Glousman described a cadaveric study comparing the accuracy of posterior and anterolateral approaches and found no statistical difference between these techniques [11]. There are no studies, to our knowledge, that compare the outcomes of different LMGI approaches.

Current literature supports the use of SDB CS LMGIs for impingement syndrome [4,5,7,12]. While outcomes have been variable, a number of studies have shown benefit from these injections with respect to pain and range of motion [5,7,12]. Over the past 10 years, point-of-care ultrasound (US) use has been rapidly growing by musculoskeletal specialists for diagnostic and therapeutic purposes. Ultrasound-guided injections (USGIs) are known to be accurate [13,14] and the use of US-guidance for SDB injections has become a common occurrence in clinical practice. US can visualize bursal fluid, bursal thickening, tendinopathy, and tendon tears [15- 17]. It is effective in guiding a needle into the SDB [18]. Research comparing the outcomes of LMGIs versus USGIs of CS into the SDB is limited in quantity and quality, but has shown a trend toward better outcomes following USGIs [14,18-22]. One theory postulates that poor outcomes following LMGIs are due to inaccuracy without direct visualization. US has been shown to improve the accuracy of bursal and intra-articular injections [14]. Only a few studies have directly compared the accuracy of LMGIs and USGIs of the SDB. In a randomized comparison, Naredo et al found that the majority of the LMGIs were inaccurately placed, whereas more than 90% of the USGIs were accurately delivered, with corresponding clinical improvement [20]. The American Medical Society of Sports Medicine (AMSSM) reviewed the data on LMGIs versus USGIs of the SDB and found that while LMGIs had an accuracy of a 81%, USGIs had an accuracy of 100% [14,20,23]. The AMSSM position statement reports that there is strong evidence that USGIs are more accurate than LMGIs of the SDB [14].

In addition to improving accuracy, we believe other factors may contribute to the better outcomes seen following USGIs of the SDB. The use of US may alter the injection approach used in SDB CS injections. US can help by identifying the area of most significant bursal thickening and distension; this allows physicians to localize CS injections to the most affected area of the bursa, potentially improving patient outcomes in comparison to the standard posterolateral approach of LMGIs. Our objective was to evaluate how point-of-care US affects the injection approach used for treatment of subacromial impingement with bursal involvement. We hypothesize that, when injections are directed based on bursal abnormalities seen on US with clinical correlation, SDB CS injections will more commonly be given anterior to the acromion, rather than directly below it, as would be done with LMGIs.


A retrospective review of the medical records and US images was performed on adult patients who received an USGI of the SDB at one academic rheumatology musculoskeletal ultrasound (MSUS) clinic. Institutional review board approval was obtained prior to chart review and data collection. Records were reviewed from December 2011- July 2014.

A query was performed for patients with an ICD-9 code for shoulder pain who received an USGI using a research patient data repository [24]. These patients were considered for inclusion in this study (n=129). Patients who received an injection at any location other than the SDB were excluded (n=62). The most commonly excluded were injections to the glenohumeral joint and biceps tendon sheath. Patients with both subdeltoid bursitis and biceps tenosynovitis were included in this study if their primary pain generator was attributed to the SDB, thus receiving an USGI of the SDB. Many patients underwent either bilateral injections or repeat injections at a later date. The decision was made to treat each of these injections as an individual case because they were frequently given in the contralateral arm and/or utilizing a different probe position.

Medical records were retrospectively reviewed for patient demographics, including age, body mass index (BMI), coexisting inflammatory conditions, and history of chronic widespread pain. The mean ± standard deviation or frequency of each characteristic was calculated. As is standard practice, patients were clinically evaluated based on history and a standard shoulder examination evaluating for impingement, biceps tenosynovitis and joint involvement prior to US examination. If documented, both the area of primary pain location identified during the history and the area of most significant reproducible tenderness to palpation on examination were noted. These areas were described as occurring primarily at the anterior, anterolateral, lateral, or posterior aspect of the shoulder.

The US evaluation and USGIs were performed or supervised by an expert MSUS-trained rheumatologist (MK). All injections were given using an in-plane needle approach with direct needle visualization throughout the procedure. It is standard practice in this clinic to direct the injection to the area of most significant abnormality (e.g. bursal thickening and fluid distension) identified on US if clinical correlation exists. If there was a discrepancy in these two parameters, bursal fluid distension was selected to take priority.

Images were reviewed by two MSUS-trained physiatry residents (LR, SK) for the following parameters: area of most significant bursal thickening, area of most significant bursal fluid collection, location of tendinopathy (biceps, subscapularis or supraspinatus), and location in which CS injection was given. All images were then reviewed and confirmed by the same MSUS-trained rheumatologist (MK). If there was a discrepancy between the two physiatry reviewers, the rheumatologist made the final interpretation. Intra-rater reliability was 100% for all reviewers on a test sample of 10 images. Inter-rater reliability between the physiatry residents (LR, SK) was 90%, while 100% inter-rater reliability was found between the rheumatologist (MK) and at least one of the physiatrists (LR or SK) for all cases.

To develop a standardized method to identify locations for the above parameters, four common shoulder probe positions were used: 1- anterior over the biceps tendon (Figure 1), 2- anterior over the subscapularis tendon (Figure 2), 3- anterolateral over supraspinatus tendon (Figure 3), and 4- lateral over the supraspinatus tendon (Figure 4). An alternate probe position was used for probe positions 3 and 4 when a patient was unable perform a modified crass position due to pain (Figure 5). A detailed description of each probe position can be found in Table 1.