Volume 90, Issue 2 , Pages 279-284, February 2009
The Effects of Scapulothoracic Bursa Injections in Patients With Scapular Pain: A Pilot Study
Article Outline
Abstract
Chang WH, Im SH, Ryu JA, Lee SC, Kim JS. The effects of scapulothoracic bursa injections in patients with scapular pain: a pilot study.
Objective
To assess the effects of steroid plus hyaluronate injections for scapulothoracic bursitis in patients with scapular pain.
Design
Prospective open-label unicenter trial with a 3-month follow-up.
Setting
University rehabilitation hospital.
Participants
Twenty-two cases of suspected scapulothoracic bursitis.
Intervention
Injections into scapulothoracic bursa were performed with steroid plus hyaluronate. Injections were administered once a week for 3 weeks.
Main Outcome Measures
Visual analog scale (VAS), Rubin scale, adverse events, and injection-associated complications.
Results
Mean outcome scores at 3-month follow-up visits showed significant improvements versus baseline (mean VAS increased from 7.8 to 2.2) (P<.05). Furthermore, mean VAS scores at 1, 2, and 3 weeks after treatment commencement showed significant improvements versus baseline (P<.05). No serious complication occurred during the study.
Conclusions
Scapulothoracic bursitis should be considered when treating patients with perimarginal scapular pain or subscapular pain. Our findings show that steroid plus hyaluronate injections into the scapulothoracic bursa provide an effective means of treating patients with scapulothoracic bursitis.
Key Words: Hyaluronic acid, Injections, Rehabilitation, Scapula
List of Abbreviations: HA, hyaluronic acid, STB, scapulothoracic bursitis, VAS, visual analog scale
NONSPECIFIC COMPLAINTS OF PAIN under the scapula are commonly encountered, and may originate from any disorder of the cervical spine or glenohumeral joint. However, in many cases, pain is not related to these structures, and in these cases, additional clinical studies are required to reveal possible causes of pain and to confirm the beneficial effect of treatment.
The scapula is a large triangular bone situated on the posterior thorax. Furthermore, the pseudojoint between the scapula and the thorax is one of the least congruent in the human body. Moreover, because there is no true bony attachment between the scapula and the axial skeleton, its stability is afforded mainly by the surrounding musculature.1 The subscapularis and serratus anterior muscles lie interposed between the scapula and the thoracic wall, and help stabilize the scapula against the chest wall and thus prevent scapular winging.2 In addition, soft tissues, such as muscle tendons and bursae, are located between the bony thorax and the scapula, and several bursae that lie in or around the scapulothoracic joint can cause scapular dysfunction and crepitus.3 The largest bursa, which may be the main source of scapular pain, lies between the serratus anterior and the chest wall.4
Nicholson and Duckworth,5 based on their operative findings and recent descriptions of bursal anatomy, suggested that injections into the scapulothoracic bursa should be considered for diagnostic and therapeutic purposes—that is, in cases of painful scapular crepitus unresponsive to conservative management. Based on their study and the scapular anatomy, we hypothesized that periscapular or subscapular pain of indeterminate cause is, in many cases, likely to originate from a scapulothoracic bursa. It has been suggested that the etiology of bursitis involves a loss of the normal gliding movement of the scapula, which causes the superior angle of the scapula to tilt forward and irritate the underlying scapulothoracic bursa, which is then compressed between the scapula and the ribs.6 We assumed that pain or tenderness at the periscapular margin originates from a scapulothoracic bursa, because the scapulothoracic bursa cannot be palpitated directly. In the present study, we undertook to devise a less invasive, safer, injection-based method for the diagnosis and management of STB.
Thus, we administered scapulothoracic bursal injections of steroid plus HA in the belief that this combination might reduce the pain caused by bursitis; the analgesic effects of steroids are probably related to their anti-inflammatory effects.7 Nevertheless, high-molecular-weight HA has been found to be effective at treating subacromial bursitis of the shoulder,8 and is thought to act as a lubricant and to have protective effects—for example, to maintain tissue structure and inhibit neovascularization—in addition to its anti-inflammatory effect.8 Here, we describe our experiences of 22 cases of STB.
Methods
Participants
Patients determined to have suspected STB based on clinical examinations were included. All patients met the following inclusion criteria: (1) a nonspecific complaint of pain under the scapula; (2) pain at the medial border of the scapula; (3) extreme tenderness at the superior angle and medial border of the scapula; and (4) a main complaint of scapular pain in cases with scapular pain combined with cervical or shoulder pain. Only patients with disabling pain were included; patients with scapular snapping but with no or mild pain were excluded. A radiograph of the scapula taken at the time of screening was used to identify and exclude cases of fracture or osteonecrosis. Candidates with pain in bilateral scapulae were also excluded in order to allow pain improvements to be investigated better. In addition, patients with absolute contraindications for the injection procedure, such as local infection, dermatologic conditions that precluded adequate skin preparation, a tumor at the injection site, a history of allergy to local anesthetic agents, severe hypovolemia, gross coagulation defects, and septicemia, were also excluded. Thirteen patients who met these inclusion criteria had visited another hospital previously and had undergone different conservative treatments—that is, 5 had received a series of trigger point injections in and around muscles of the scapula, 9 had undergone physiotherapy such as superficial heat and deep heat, and 11 patients had been administered oral medications. However, none of these treatments resulted in noticeable pain improvement.
Twenty-two (6 men and 16 women) of these 24 patients provided informed consent, completed the treatment schedule, and attended a 3-month follow-up after the first injection. Five patients had a history of a direct shoulder contusion caused by a traffic accident, but the other 17 had no trauma or surgical history related to the shoulder girdle.
All patients provided written informed consent and were provided an explanation of the study goals. All procedures were approved by the institutional ethics committee. In addition, it should be noted that HA administration as presented in this study constitutes off-label use.
Injection Procedure
With the affected arm in a position of extension, internal rotation, and adduction, with the patient laying prone and attempting to reach the upper spine—that is, similar to the surgical “chicken wing” position (fig 1)—bony landmarks used for orientation in the large scapulothoracic space and serratus anterior bursa are absent. Therefore, as suggested by Ruland et al4 and to avoid touching main neurovascular structures, we inserted the injection needle via a portal midway between the spine of the scapula and the inferior angle of the scapula and 3 to 4 fingerbreadths from the vertebral border of the scapula (fig 2). Portal placement near the vertebral border of the scapula should be avoided because it requires a more vertical spinal needle orientation, which increases the likelihood of penetrating the thoracic cavity and injuring the dorsal scapular artery and nerve.4 This portal courses through subcutaneous tissue, the trapezius, and the interval between the rhomboid major and minor muscles before penetrating the serratus anterior space. Accordingly, needles were inserted into the primary target—that is, the bursa between the serratus anterior and the lateral chest wall. The 22 patients were injected with 40mg triamcinolone containing 4mL 0.5% lidocaine followed by 20mg high-molecular-weight HA (2mL, 1% hyaluronan, molecular weight 940–1020kd).a The doses injected were arbitrary, because no guideline has been established. These injections into the scapulothoracic bursa were administered once weekly for 3 weeks. During this period, patients were allowed to take previously prescribed oral medications, such as nonsteroidal anti-inflammatory drugs and muscle relaxants, but were not permitted any physical therapy or new medication.
Fig 1.
Position adopted for scapulothoracic bursa injections; the patient was asked to try to reach the high spine with the affected arm while lying prone to place the arm in an extended, internally rotated, adducted position.
Fig 2.
Needle placement: visualization portal was placed midway between the spine of the scapula and the inferior angle of the scapula (a 6-cm spinal needle was used).
Evaluation Method
This pilot study was a prospective, open-label, unicenter study. Before study commencement, sex, age, affected side, symptom duration, and prior treatment were documented. A VAS (range, 0–10)9 and the Rubin scale10 were used to assess pain and to determine treatment success rates, respectively. Response to treatment was recorded as follows: (1) poor—no relief; (2) fair—mild, intermittent pain; (3) good—mild, intermittent discomfort without pain; and (4) excellent—complete relief of pain. Baseline measurements were taken before first injections, and other measurements just before subsequent injections. Therefore, patients were examined at the following times: at baseline, and then at 1, 2, and 3 weeks after the first injections, and again at 3 months after the first injections. Frequencies and severities of adverse events and injection-related complications were monitored throughout.
Diagnostic criteria did not include sonographic findings, but 8 cases underwent ultrasoundb of the affected scapula using a scanner with a 5 to 12MHz linear-array transducer. During these examinations, affected arms were positioned in extension, internal rotation, and adduction, with patients lying prone and attempting to reach the high spine—that is, the injection position.
Statistical Analysis
Analysis of variance with the Tukey B test were used to analyze VAS differences before and after treatment. Statistical analysis was performed using SPSS version 13.0c for Windows, and statistical significance was accepted for P values of less than .05.
Results
Participant characteristics are summarized in table 1. Twenty-four patients met the inclusion criteria, and 22 of them completed their series of 3 weekly injections. Symptom duration was based on the presence of intractable pain, not on vague discomfort or mild pain. No participant showed scapular winging by physical examination. Snapping remained in 8 of 9 patients after treatment, although all experienced pain reduction.
Table 1. Baseline Characteristics of the 22 Scapulae
| Patient | Age (y)⁎ | Sex | Side | Duration | Previous Treatment | Trauma History | Neck Pain | Shoulder Pain | Bursitis in sonography |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 40 | F | Left | 3mo | Med | + | − | + | |
| 2 | 46 | M | Right | 1wk | − | − | + | ||
| 3 | 40 | F | Right | 6mo | Med, P | + | + | + | |
| 4 | 24 | F | Right | 2wk | − | − | − | ||
| 5 | 36 | F | Right | 18mo | Med,P | − | + | − | |
| 6 | 58 | F | Right | 2mo | − | + | + | + | |
| 7 | 34 | F | Left | 2wk | − | + | + | ||
| 8 | 41 | F | Right | 1wk | − | + | + | + | |
| 9 | 46 | F | Left | 3mo | Med,P | − | + | + | |
| 10 | 61 | M | Left | 2y | Med,P,T | − | − | − | + |
| 11 | 28 | M | Right | 3mo | + | + | − | ||
| 12 | 36 | M | Left | 2y | Med,T | − | + | + | − |
| 13 | 30 | M | Left | 6mo | Med | − | − | − | + |
| 14 | 44 | F | Right | 6mo | Med | − | − | + | |
| 15 | 39 | F | Right | 4y | Med,P,T | − | + | − | |
| 16 | 42 | F | Left | 5mo | P | + | − | + | |
| 17 | 34 | F | Left | 1wk | − | + | + | + | |
| 18 | 36 | F | Right | 1mo | P,T | + | + | + | |
| 19 | 59 | F | Right | 3mo | − | + | + | + | |
| 20 | 36 | F | Left | 17mo | Med,P | − | + | − | |
| 21 | 34 | F | Right | 3wk | − | + | + | + | |
| 22 | 39 | M | Left | 3y | Med,P,T | − | + | − |
⁎Average age: 40.1±9.5. |
Pain Measurements
VAS scores at 3-month follow-up visits after the first injections were significantly lower than at baseline (mean, 7.8 to 2.2; P<.05; fig 3), as were VAS scores at 1, 2, and 3 weeks after the first injections (P<.05; see fig 3). Mean VAS at 2 weeks tended to be lower than at 1 week (P>.05). However, mean VAS at 3 weeks was significantly lower than at 1 week, but no significant difference was observed between VAS scores at 2 and 3 weeks. In addition, when we evaluated the effects of injections using the Rubin scale at 3-month follow-up visits after the first injections, the overall success rate as determined by the Rubin scale was 95.5%. Furthermore, when participants were asked to rate analgesic effect at 3-month follow-up visits, 10 patients (45.5%) replied excellent, 7 (31.8%) good, and 4 (18.2%) fair. Only 1 patient considered the analgesic effect of the injections to be poor.
Fig 3.
Changes in VAS pain scores during and after treatment. All follow-up checks were done after the first injection.
Sonographic Outcome
Seven of 8 patients who underwent sonography at baseline revealed fluid collection in the scapulothoracic bursa (fig 4). A magnetic resonance imaging study performed on 1 patient (patient 12; see table 1), in whom no scapulothoracic bursa was revealed by sonography, also failed to visualize the scapulothoracic bursa (fig 5), and 3-dimensional computed tomography scans of this patient showed no bony abnormalities, such as osteochondroma or exostoses (fig 6).
Fig 4.
Transverse high-resolution ultrasonographic image of the scapulothoracic bursa. The arrows show fluid collection in the bursa. Abbreviations: L, lung; R, rib; S.A, serratus anterior.
Fig 5.
T2-weighted fat saturation magnetic resonance image, which failed to reveal the scalupulothoracic bursa. The arrows show the serratus anterior. Abbreviations: R, rib; S, scapula.
Fig 6.
Three-dimensional computed tomography image showing no bony abnormalities, such as osteochondroma or exostoses.
Adverse Events
Eight of the 22 participants experienced focal postinjection pain after 1 or more injection, but this pain was mild to moderate and self-limited in all, and no supplementary treatment was required. Interestingly, no patient who experienced postinjection pain refused further injections. No serious complications, such as pneumothorax or infection, or symptoms attributable to the side effects of steroid or HA were encountered.
Discussion
Baseline studies on periscapular or subscapular pain originating from the scapula are inadequate. Snapping scapula syndrome, which has also been referred to as superior scapular syndrome, retroscapular pain, and retroscapular creaking,5, 11 is one such problem, and was first described by Boinet in 1867. Historically, the causes of snapping scapula syndrome have been attributed to bone, muscle, or bursal abnormalities affecting scapulothoracic movement.4 However, snapping scapular syndrome is not well understood, and localized anatomic causes are rarely identified. Numerous pathophysiologic conditions can lead to snapping scapula: muscle atrophy from disuse or nerve injury, bursa inflammation, tuberculosis, syphilitic lesions, structural spinal deformities (including scoliosis and thoracic kyphosis), Luschka tubercle, bony abnormalities (including osteochondromas of the rib and scapula), and healing fractures of ribs or scapulae with bony angulation or increased callus.1 Furthermore, comparatively few epidemiologic or clinical studies have been conducted on the prevalence and etiology of snapping scapular syndrome or on available treatment options. Confusion arises because in the literature, STB and snapping scapular syndrome are both used to describe what is considered to be a single entity. Moreover, although a snapping scapula is annoying, it is only occasionally painful or disabling.12 Therefore, in the present study, we focused on patients with pain or a disabling condition, and those with suspected STB with or without a snapping sound.
The etiology of symptomatic STB has been inferred but not proven,3 and clinical studies have presented histologic findings of bursitis, skeletal muscle intrafascicular fibrosis, shoulder girdle muscle atrophy, and edema.3, 11 As suggested by the present study, STB is probably the main source of scapular pain. On the other hand, some cases of scapulothoracic bursa have presented with a painless palpable mass,13, 14 and thus, we considered that scapular bursa per se might not be the cause of scapular pain. Accordingly, we recruited only patients with suspected STB and scapular pain. This distances our study from a previous study,14 in which patients were recruited with distended scapulothoracic bursa without scapular snapping.
The present study demonstrates that scapulothoracic bursa injections resulted in excellent outcomes, and that they had a substantial analgesic effect at 3 months after the first injections. Furthermore, VAS scores and Rubin scales were found to improve during and after the treatment course. On the other hand, a recent study of corticosteroid injections found that corticosteroids provide only temporary relief.15 Although the patients recruited obviously differed from those of the present study, it is evident that nonsteroid-based treatments are required. In the present study, we decided to examine the effects of combined steroid and HA delivered by injection. In addition to its anti-inflammatory effect, HA is viewed as a slow-acting symptom-modifying agent that maintains pain relief for several months.16 In fact, a previous study on knee osteoarthritis suggested that HA and steroid intra-articular injections act synergistically, because combined injections were found to reduce pain more rapidly and to lower pain levels more than HA alone.17 This suggestion is also supported by the findings of an in vitro study.18 In another study, steroid injections combined with HA also produced good results in shoulder joints.19 Furthermore, HA produced good results when used to treat subacromial bursitis of shoulder,8 and in another study, it was postulated that the viscosity of HA improves sliding properties or prevents adhesions,20, 21, 22, 23 and that it lubricates deep bursa.24
The regimen used in the present study was derived from reports about HA injections into the shoulder,25, 26 in which injection methods were based on reports concerning knee joint injections. Studies about HA injections into the knee joint have recommended that injection be administered at 1-week intervals, and have reported that the effect of treatment begins during the second week.27, 28 In the present study, the first injection provided about 80% of the benefit of treatment (see fig 3). However, it is evident that further studies are required to determine optimal treatment schedules and doses.
A blind injection technique was used in the present study, and thus, we cannot exclude the possibility of a triggering effect on the serratus anterior and/or subscapularis muscles because of delivery inaccuracy. Furthermore, the effect of steroid on undetected tendinitis of the muscles inserting into the scapula could also have relieved pain. Therefore, a further study using sono-guided injection is required. In most cases in the present study, snapping sounds did not decrease in parallel with pain. However, in those without a serious underlying disease, a snapping sound without any discomfort or pain does not require treatment, and our experiences indicate that it is not necessary to treat this condition specifically when treating STB.
Several studies have described the use of injection-based therapies for treating the scapulothoracic joint.1, 3, 15, 29, 30 However, only 2 focused on injection-based therapy and provided a detailed description of the injection procedure used.15, 30 It has been reported that hydrocortisone and local anesthetic administration under the scapula in the area of crepitus temporarily relieves pain without affecting the snapping sound.15 Furthermore, in a previous retrospective study,30 a fluoroscopically guided scapulothoracic injection of lidocaine was administered to 20 patients with pain deep at the medial border of the scapula. However, these subjects were not diagnostically confirmed to have STB, and the presence of STB was confirmed by using contrast medium only after the procedure, regardless of whether the fluoroscopically guided injection was administered accurately. However, compared with sono-guided injections, fluoroscopically guided injections are limited by an uncertain needle location. In addition, because the most tender point was targeted in this previous study, observed effects were possibly a result of trigger point release or bursa injection. Furthermore, in this previous study, although a significant reduction in pain was achieved in 20 patients, only 7 patients were confirmed to have received an injection in the scapulothoracic bursa, 8 patients were injected in the intramuscular area, and 5 were injected in both bursa and muscle. The present study is also limited by the use of a blind injection technique, although this technique,4 which involves consideration of anatomic features, is known to be safe. However, we believe that the findings of the present study are meaningful, because combined steroid and high-molecular-weight HA injections were found to lengthen the effect period.
Study Limitations
The present study did not include assessment tools, such as functional examinations, range of motion studies, and shoulder muscle power measurements, because they inadequately evaluate STB, which also explains, in part, why STB has received comparatively little research attention. For example, no participants in the current study had ever been informed that the pain probably originated from the scapula. Furthermore, the inclusion criteria applied during the present study did not include symptom duration. In fact, we reported duration of intractable pain, and not of vague discomfort or mild pain, which, had it been included, would have increased symptom duration. Instead of administering injections into scapulothoracic bursae, we could have adopted another method of treatment or allowed time for spontaneous recovery in patients with a brief symptom duration. However, our patients had intractable pain, and no information was available that adequately proved the effects of other forms of conservative treatment. In fact, a search of the literature revealed that no other treatment has resulted in a noticeable pain improvement. Accordingly, we decided to proceed with the steroid/HA injections into the scapulothoracic bursa. However, although no previous series of this size has been conducted to evaluate the effects of injections in STB, a 3-month follow-up period is wholly inadequate for determining long-term effects. Having considered the results obtained and limitations of the present study, we suggest that further studies be conducted on the following: (1) the effects of injecting HA, steroid, or HA plus steroid; (2) the diagnostic performances of objective imaging tools, like ultrasonography, in STB; (3) long-term treatment effects; (4) the optimization of doses and schedules; (5) the merits of sono-guided administration; and (6) the effects of treatment on subjects with different symptom durations.
Conclusions
In conclusion, in cases with pain or disability in the scapular area not related to a cervical or shoulder problem, injections into the scapulothoracic bursa offer a sound therapeutic and diagnostic approach. Therefore, we recommend that STB should be considered in patients with an indeterminate scapular pain, and suggest that steroid plus HA injections into the scapulothoracic bursa provide an effective diagnostic and therapeutic means in patients with scapular pain.
Suppliers
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PII: S0003-9993(08)01606-7
doi:10.1016/j.apmr.2008.07.027
© 2009 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
Volume 90, Issue 2 , Pages 279-284, February 2009
