Surgical Treatment of Patients with Thoracic Outlet Syndrome Caused by the Changes in the Anterior Scalene Muscle

The aim of this study is the recording of the variations of the course of the upper trunk (UT) of the brachial plexus (BP) and their clinical significance for the thoracic outlet syndrome (TOS) and the anesthetic blockade of the BP. Five different anatomical variations of the course of the UT of the BP, in relation to the anterior scalene muscle (ASM), were observed in 24 out of the 186 sides of the 93 cadavers we studied (12.9%). The C5 root was passing anteriorly to the ASM in six cases. The UT was located anteriorly to the ASM in four cases and was perforating the ASM's belly in 12 cases. In one cadaver, the ASM was double and the UT was passing between the two bellies of the double ASM. Finally, in another cadaver, the C5 root was found to be anterior to the anterior scalene muscle, while the C6 root was perforating the ASM's belly. These variations are predisposing factors for the TOS; they cause specific symptomatology and require a different surgical approach in comparison with other causes of the syndrome. Moreover, knowledge of these is important during the performance of the anesthetic blockade of the BP.

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RELATO DE CASO: SÍNDROME DO DESFILADEIRO TORÁCICO

Revista de Patologia do Tocantins ◽

10.20873/uft.2446-6492.2018v5n3p24 ◽

2018 ◽

Vol 5 (3) ◽

pp. 24-27

Author(s):

Tatiane Silva Gonçalves ◽

Raíssa Nunes Bezerra De Sá ◽

Jéssica Neto Ferreira Pacheco ◽

Alexis Alison Cardozo Leite ◽

Pedro Manuel Gonzales Cuellar

Keyword(s):

Brachial Plexus ◽

Thoracic Outlet Syndrome ◽

Vascular Complications ◽

Contributing Factors ◽

Scalene Muscle ◽

Insidious Onset ◽

Analgesic Medication ◽

Bone Anomalies ◽

Anterior Scalene Muscle ◽

Cervical Ribs

RESUMO Introdução: A Síndrome do Desfiladeiro Torácico (SDT) é uma entidade clínica com sintomatologia diversa, decorrente de compressão anormal do plexo braquial, na região do desfiladeiro torácico. Esta compressão é exercida, na maioria das vezes, pelo músculo escaleno anterior, mas pode resultar também da existência de bandas musculofibróticas, alteração da morfologia da primeira costela, costelas cervicais e músculos anômalos. A SDT pode ser classificada nos tipos vascular e neurogênico. Descrição do caso: Paciente, sexo feminino, 27 anos, com quadro de dor e parestesia, há dois anos, de início insidioso, em 4º e 5º quirodáctilos e, posteriormente, com progressão para todo membro superior esquerdo (MSE). Procurou Unidade de Pronto Atendimento, sendo prescrito apenas medicação analgésica. Após três dias, apresentou intensificação da dor, associada a palidez e parestesia de MSE procurando atendimento no Hospital Geral de Palmas. Discussão: A SDT acomete mais mulheres entre 20-50 anos, com vários fatores contribuintes, chegando a limitar as atividades diárias e laborais. O tratamento clínico, frequentemente, é a conduta inicial, procurando aliviar os sintomas. Em geral, o tratamento cirúrgico tem indicação em 15 % dos casos, quando a síndrome é decorrente de anomalias ósseas sintomáticas e complicações vasculares. Palavras-chave: Síndrome do Desfiladeiro Torácico; Costela Cervical; Plexo Braquial. ABSTRACT Introduction: Thoracic Outlet Syndrome (TOS) is a clinical entity with diverse symptomatology due to abnormal compression of brachial plexus in the thoracic outlet region. This compression is often carried out by the anterior scalene muscle, but it may be a result from the presence of musculofibrotic bands, alteration of the first rib morphology, cervical ribs and anomalous muscles. TOS can be classified into vascular and neurogenic types. Case description: Patient, female, 27 years old, with pain and paresthesia, since two years ago, insidious onset, in 4th and 5th fingers, and later with progression to all left upper limb (LUL). She looked for Emergency Care Unit, and only analgesic medication was prescribed. After three days, she presented pain intensification, associated with pallor and paresthesia of LUL, looking for care at the General Hospital of Palmas. Discussion: The TOS affects more women between 20-50 years old, with several contributing factors, limiting daily activities and work. The clinical treatment, often, is the initial conduct, seeking to relieve symptoms. In general, the surgical treatment is indicated in 15% of cases, when the syndrome is due to symptomatic bone anomalies and vascular complications. Keywords: Thoracic Outlet Syndrome; Cervical Rib; Brachial Plexus.

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Throwing can Increase the Stiffness of the Scalene Muscle

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00402 ◽

2020 ◽

Vol 8 (7_suppl6) ◽

pp. 2325967120S0040

Author(s):

Tetsuya Takenaga ◽

Satoshi Takeuchi ◽

Hideki Murakami ◽

Katsumasa Sugimoto ◽

Masahito Yoshida

Keyword(s):

Surgical Treatment ◽

Brachial Plexus ◽

Shear Wave ◽

Shear Wave Elastography ◽

Muscle Stiffness ◽

Deep Part ◽

Baseball Players ◽

Scalene Muscle ◽

Throwing Motion ◽

Anterior Scalene Muscle

Objectives: Thoracic outlet syndrome (TOS) has been reported as a set of symptoms due to the compression of the brachial plexus and subclavian vessels in the region of the thoracic outlet1. As a type of TOS, scalenus anticus syndrome involves the compression of the brachial nerves as they pass through the interval surrounded by the anterior and middle scalene muscles, and the first rib bone or cervical rib2. Recently, exercise-induced TOS is becoming more common in athletes, especially for those who perform repetitive overhead and hyperabduction maneuvers with upper limbs, such as baseball players. However, the effect of throwing on the stiffness of the scalene muscles is unknown. Thus, the purpose of this study was to quantitatively measure the stiffness of the scalene muscles using real-time shear wave elastography (SWE). The stiffness of scalene muscles was hypothesized to increase for the throwing side of baseball players. Methods: Thirty college baseball players (age range 19 to 21 years) were included for this study. Ultrasonic SWE with a 2-10 MHz linear array probe transducer (Aixplorer; SuperSonic Imagine, Aix-en-Provence, France) was used to assess the stiffness of the anterior and middle scalene muscles. Each participant was sited. The measurements were performed in two arm positions; 1) adducted and neutral rotation of the shoulder 2)90 degree of abduction and external rotation of shoulder with elbow flexed to simulate a clinical examination known as Roos test3. In both of the arm positions, the transducer was positioned just superior to the clavicular bone, parallel to its axis. Transducer was moved superiorly and tilted to visualize the superior surfaces of the anterior and middle scalene muscles parallel to the surface of the fifth cervical nerve simultaneously (Figure 1A). In this position, shear wave elastography was performed to measure the elasticity of each scalene muscle as its stiffness. Each muscle was divided into superior and deep areas. In both areas of each muscle, three 3mm-diameter circles were set to measure the elasticities of the scalene muscles and its averaged data in each area was defined as each stiffness (Figure 1B). A repeated-measures analysis of variance (ANOVA) was used to compare the elasticity of superior and deep areas in anterior and middle scalene muscles in throwing and non-throwing side. Values of p<0.05 were considered statistically significant. Results: For the throwing side, higher stiffness was found in the deep part of the middle scalene muscle compared to the superior and deep parts of the anterior scalene muscle with an adducted and neutrally rotated shoulder (p=0.0433). Moreover, the muscle stiffness was significantly higher in the superior and deep part of the middle scalene muscle than in the superior and deep parts of anterior scalene muscle in an abducted and externally rotated position of shoulder (p =0.00187). Meanwhile, no significant difference was found in the anterior and middle scalene muscles for the non-throwing side in both arm positions. Conclusion: In professional athletes with TOS who experienced surgical treatment, moderate to severe hypertrophy of the anterior scalenus muscles has been reported to be found4. Meanwhile, although the stiffness of the scalene muscles can be also related to the compression on the brachial plexus and on subclavian vessels in the region of the thoracic outlet, its quantitative measurements in the scalene muscles has not been reported. In this study, at throwing side, the muscle stiffness significantly increased in the superior area of middle scalene muscle in throwing side. While no contribution was identified in the scalene muscles at non-throwing side. As a result, repeat throwing motion can increase the stiffness of the middle scalene muscle. As a result, the brachial plexus and/or the subclavian artery could be compressed at the interscalene triangle. Throwing athletes with TOS should be treated, considering the stiffness of the middle scalene muscle, even conservative or surgical treatment. Our study was the first study to evaluate the effects of throwing on the stiffness of the scalene muscles in throwing athletes. Repetitive throwing motion can affect the stiffness of middle scalene muscle. Reduction of the middle scalene muscle should be considered to treat throwing athlete who has TOS. [Figure: see text]

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