Case Report
http://dx.doi.org/10.14517/aosm14007 pISSN 2289-005X·eISSN 2289-0068
Intramuscular calcification of the subscapularis muscle: a case report Tae Hyun Wang, Jung Hoei Ku, Hyung Lae Cho, Hong Ki Jin Department of Orthopaedic Surgery, Good Samsun Hospital, Busan, Korea
Calcific tendinitis of the shoulder has been widely described in the literature. It occurs most commonly near the insertion site of the rotator cuff tendons, particularly involving the supraspinatus tendon. We report a case of a 59-year-old female patient with an atypically located calcification in the muscular portion of the subscapularis. The patient complained of severe shoulder pain and limited range of motion that were complicated with a tingling sensation of the affected upper arm and hand. Magnetic resonance imaging results confirmed that the calcific material was located near the musculotendinous junction and edema of the soft tissue extended to the adjacent brachial plexus, which would also be suggestive of an infection or a tumor. After ultrasound-guided needling of the calcific deposit and corticosteroid injection therapy, the patient showed significant pain relief and improved range of motion. Calcific tendinitis can occur within the involved muscle and its clinical symptoms vary according to the type of lesion. Keywords: Shoulder; Subscapularis; Calcific tendinitis; Intramuscular loculation; Ultrasound-guided needling
INTRODUCTION Calcific tendinitis of the shoulder is a relatively common disorder and is characterized by acute pain during resorption of the calcific deposits, which is why it is often referred to as the chemical furuncle [1]. Calcification in the shoulder occurs most commonly in the supraspinatus tendon (80%), and in lesser amounts in the infraspinatus tendon (15%) and the subscapularis (5%) [2]. Because the pathophysiology of calcific tendinitis is related to the degenerative changes of the tendon, calcific tendinitis generally occurs in the hypovascular intratendinous portions of the rotator cuffs, which are close to the rotator cuff insertion site [2], but not in the intramuscular regions of the rotator cuffs. Intramuscular calcification induces a wide range of reactive changes in the surrounding soft tissues, similar to what is seen for a tumor or infection, but rarely involves adjacent neurovascular structures [3]. Acute calcific tendinitis responds well to conservative measures
Arthroscopy and Orthopedic Sports Medicine
AOSM
such as anti-inflammatory medications or needling, and a relatively simple ultrasound guided method can be used for the latter measure at an outpatient’s clinics [4]. The authors report a case of an atypical calcification at the subscapularis treated successfully by ultrasound-guided needling and corticosteroid injection.
CASE REPORT A 59-year-old female patient complained of acute pain and restrictive range of motion of the right shoulder at our initial consultation. Her medical history showed that she had been conservatively treated for intermittent shoulder pain for 1 year prior to the consultation. The patient complained that night pain combined with resting pain had worsened from the night before. Physical examination of the patient revealed severe tenderness and a slight edema spanning the anterior shoulder near deltopectoral interval and an inability to actively elevate the arm.
Received April 28, 2014; Revised June 17, 2014; Accepted June 19, 2014 Correspondence to: Hyung Lae Cho, Department of Orthopaedic Surgery, Good Samsun Hospital, 326 Gaya-daero, Sasang-gu, Busan 617-718, Korea. Tel: +82-51-310-9289, Fax: +82-51-310-9348, E-mail:
[email protected] Copyright © 2015 Korean Arthroscopy Society and Korean Orthopedic Society for Sports Medicine. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. CC
Arthrosc Orthop Sports Med 2015;2(1):55-59
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Tae Hyun Wang, et al. Intramuscular calcification of the subscapularis muscle
Further physical examination could not be performed as the patient was under severe pain. Although motor and sensory functions of the elbow joint and structures below it were normal, the patient expressed an diffuse tingling sensation in the affected upper arm and hand. Although results of peripheral blood examination and white blood cell counts were normal, erythrocyte sedimentation rate
and C-reactive protein level increased to 22 mm/hr and 11.50 mg/dL, respectively. Systemic fever or focal redness in the affected shoulder were not observed in the patient. Plain radiological results of anteroposterior and apical oblique views show formation of circular calcification in the subglenoid and the axillary areas (Fig. 1). T2-weighted images of horizontal sections of the magnetic resonance
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Fig. 1. Initial radiographs of the right shoulder. Anteroposterior (A) and apical oblique (B) radiographs show calcific deposition (arrows) in subglenoid and axillary area.
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Fig. 2. Magnetic resonance images of the right shoulder. T2-weighted axial (A), oblique coronal (B) images show circular, hypointense calcific deposits (asterisks) with hyperintense edema surrounding the center of the subscapularis muscle and sagittal image reveals that soft tissue edema is extended to the adjacent brachial plexus (arrows) (C). (D) T1weighted sagittal image shows the re lationship between the hypointense calcific material and the axillary artery (arrowheads).
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Tae Hyun Wang, et al. Intramuscular calcification of the subscapularis muscle
imaging (MRI) findings showed that an intramuscular low signal intensity, circular signal near the musculotendinous junction of the subscapularis representing the calcific material. A high intensity signal in the surrounding soft tissue and the subscapularis was indicative of an reactive edema (Fig. 2A). Cross-sectional and sagittal T2-weighted MRI images showed that the calcification was in the center of the subscapualris and the high signal intensity in the surrounding soft tissue extended to the brachial plexus (Fig. 2B, C). The sagittal image further showed that the calcification was in close proximity to the axillary artery (Fig. 2D). Although the patient showed trivial improvements in pain after receiving nonsteroidal antiinflammatory drug (NSAID) injections, as the range of shoulder motion was still restrictive and nocturnal pain still persisted, we decided to treat the patient through ultrasound guided needling. After sterilization, the site of calcification was first confirmed through ultrasound
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with the patient in supine position (Fig. 3A). Under local anesthesia of the subscapularis and soft-tissue adjacent to the calcification, a puncture was made using an 18 G spinal needle, with the patient’s upper arm in external rotation. Then, ultrasound guided needling was performed by extending the spinal needle towards the longitudinal axis along the subscapularis to the site of calcification (Fig. 3B). During the procedure, the calcific material, toothpaste-like in substance, was drawn out through the needle puncture (Fig. 3C). Instead of using irrigation to drain out the calcific material, it was removed by repeated drainage using a stylus. After the procedures, 40 mg of triamcinolone with 1% of lidocaine 1 mL was injected at the site of drainage. Smear and culture tests were negative for possible bacterial infections of calcific material. The shoulder pain was dramatically resolved immediately after treatment and was completely resolved by the next day. Two days after the treatment, the amount
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Fig. 3. Ultrasound-guided needling. Long-axis sonography shows a hyperechoic focus of intramuscular calcification (A) and 18-gauge needle is directed towards the calcification (B). (C) Photograph after needling reveals a tooth-paste like calcific material.
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Fig. 4. Anteroposterior radiographs of the right shoulder 2 days (A) and 7 days (B) after needling show complete resorption of the calcific deposit.
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Tae Hyun Wang, et al. Intramuscular calcification of the subscapularis muscle
of calcific material was significantly diminished, which we confirmed through plain radiological findings (Fig. 4A) and range of motion of the shoulder returned to normal and tingling sensation of the upper arm and hand disappeared. One week after treatment, we were able to confirm the complete removal of the calcific material (Fig. 4B) and blood tests showed that indices returned to normal levels. At 3 month follow-up, the patient was completely relieved from shoulder pain and had achieved normal range of motion and muscle strength. Radiological findings showed that calcification had not recurred.
DISCUSSION The prevalence of calcific tendinitis in the subscapularis muscle is not as rare as that of the supraspinatus muscle. However, as in the supraspinatus muscles, calcific ten dinitis tends to occur in hypovascular regions of the subscapularis tendon insertion site, also called the critical zone [5,6]. In some cases, calcific tendinitis leads to stenosis of coracohumeral interval or subcaracoid impingement syndrome [6]. However, up to date there has been no report of calcification in the muscles near the musculotendinous junction, a site much more proximal than the critical zone. Especially, in this case report we show through radiological findings calci fication only at the musculotendinous junction and an absence of calcification at the tendon insertion site. This led us to speculate that calcification we see at the musculotendinous junction is its primary site of origin rather than being a secondary site with its source of origin as the tendon insertion site. This allowed us to put forward a possibility that calcific tendinitis can occur not only in tendon insertion sites but also in sites within muscles of musculotendinous junctions. As seen in this report, intramuscular calcification itself is seen as a low signal intensity in both T1- and T2-weighted MRI images. However, surrounding muscles and soft tissue may show a high signal intensity on T2-weighted images if edema or infections have been elicited, thus in such cases, the patient’s differential diagnosis should include tumor, infectious diseases, myositis ossificans, and focal myositis [7,8]. Although the current report did not take a biopsy, plain radiological findings and past history of the patient are typical of acute calcific tendinitis. MRI findings showed a distinctive and a homogenous low signal intensity typical of calcification rather than a nonhomogenous intralesional septa [7] or a zonal pheno
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menon [8] that is typical of calcified hemangioma or myositis ossificans, allowing us to differentially diagnose this condition. As the erythrocyte sedimentation rate and C-reactive protein levels increased dramatically at the acute phase, the condition of the patient in this case report could have been misdiagnosed as a bacterial infection. However, we ruled this out as the patient showed no signs of systemic symptoms such as fevers or chills and was negative for bacterial culture or smear tests. Another reason a bacterial infection was not considered was because we saw that the patient’s C-reactive protein level, which are known to sometimes increase after surgery or injury and return to normal levels naturally after time [9], returned to normal levels after one week of treatment even though antibiotics were not taken. Mileto and Gaeta [3] observed from MRI findings that the change in signal intensity from low to high in the supraspinatus muscles of patients when patients contract acute calcific tendinitis at the insertion site extended to musculotendinous junction is like the change in signal intensity seen in patients with ParsonageTurner syndrome. Parsonage-Turner syndrome is a rare and unusual syndrome that refers to the denervation of one or more of the rotator cuff muscles caused by an acute infection of the brachial plexus, resulting in a high signal intensity on an MRI scan. Although its MRI finding is similar to calcific tendinitis in that similar pattern of high signal intensity change is seen at the supraspinatus muscle, unlike patients with calcific tendinitis, ParsonageTurner patients do not show any intramuscular calcification [10]. If calcific tendinitis and a reactive inflammation occur together at the proximal subscapularis, due to the close anatomical position, the brachial plexus may be irritated. The lateral and posterior cord of the brachial plexus, which is the origin of the nerves such as the muscul ocutaneous, medial, axillary, and the radial nerves, is 2 cm from the glenoid rim and on the surface of the sub scapularis. Therefore, it is advised that surgeons inter vening the subscapularis through anterior surgical approach or its proximity are aware of its associated anatomical structures, such as the brachial plexus [11], as administering local anesthesia or handling surgical tools may cause damage [12]. Since we did not carry out an angiography or an electromyography, we cannot determine whether the tingling sensation of the upper arm and hand that the patient felt is the result of an atypical referred pain from the shoulder, the result of
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Tae Hyun Wang, et al. Intramuscular calcification of the subscapularis muscle
compression of the axillary artery, or irritation of the brachial plexus. However, as the sagittal images of the MRI scans showed that the edema in the adjacent soft tissue of the calcification extends to the posterior cord of the brachial plexus, which is the origin of axillary and radial nerves, we can postulate that a nerve irritation symptom may have been induce to a certain extent. Treatment modalities of acute calcific tendinitis generally include conservative methods such as NSAIDs, extracorporeal shock wave therapy, steroid injection, and multiple needling of the calcification. Of these, multiple needling, introduced by Patterson and Darraach [13] has been used regularly to effectively treat calcific tendinitis. Needling is known for its effectiveness in lowering the intratendinous pressure, which allows swift pain relief, draining out the calcification deposits, and stimulating the resorption of the deposits. We successfully employed the ultrasound-guided needling technique, which was recently described in another report, to remove the calcification because the procedure is relatively easy
to follow in an oupatient’s setting, there is no radiation exposure, and the site of calcification can be accurately determined, a puncture can be made at that specific site, and associated tendons are not unnecessarily damaged [4,14]. Calcific tendinitis of the shoulder tends to occur at the tendon insertion site, but in rare cases it can occur in musculotendinous junctions. Calcific tendinitis in these regions leads to reactive changes in adjacent soft tissue that must be differentiated from soft tissue changes that result from infections and tumors. If the calcific tendinitis occurs in the subscapularis of the rotator cuffs it could even induce a irritation sign of the adjacent brachial plexus leading to effective treatment when ultrasound guided needling is used.
CONFLICT OF INTEREST No potential conflict of interest relevant to this article was reported.
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