Materiały źródłowe

• #1 Thoracic Outlet Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK557450/

  Thoracic outlet syndrome (TOS) manifests when pressures in the thoracic outlet increase to the point of impinging vessels or nerves. […] Thoracic outlet syndrome (TOS) is a nonspecific diagnosis representing many conditions that involve the compression of the neurovascular structures that pass through the thoracic outlet. […] The cause of thoracic outlet syndrome (TOS), conceptually, is straightforward. It manifests due to the compression of various structures in the thoracic outlet. Anatomic abnormalities are likely culprits for this increased pressure in the region. Cervical ribs, extra ribs typically arising from the seventh cervical vertebrae, is one of the most common offenders for thoracic outlet syndrome. […] Soft tissue components are also major contributors to TOS. Fibrous muscular bands can cause TOS. Tumors or cysts in the thoracic outlet can also increase pressure, thus generate the symptoms seen in TOS.

• #1 Thoracic Outlet Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK557450/

  Thoracic outlet syndrome can present in specific athletes that engage in repetitive motions that involve extreme abduction and external rotation such as competitive swimmers. A classic presentation in a swimmer would be the athlete reporting pain, tightness, or numbness in the neck or shoulder area when their hand enters the water.

• #2 Thoracic outlet syndrome – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/thoracic-outlet-syndrome/symptoms-causes/syc-20353988

  Thoracic outlet syndrome is a condition where irritation or compression of nerves and vessel can happen within the thoracic outlet. And the thoracic outlet is the space between the collar bone and the first rib. So when this irritation or compression happens, it causes different kinds of symptoms that can be nerve in nature or vessel-related in nature and that’s what caused the thoracic outlet syndrome phenomenon. […] Thoracic outlet syndrome is often caused by compression of the nerves or blood vessels in the thoracic outlet, the area between the neck and shoulder. The cause of the compression varies and can include: […] Differences in anatomy. Some people are born with an extra rib in the neck found above the first rib. The extra rib, known as a cervical rib, can compress nerves or blood vessels. There also may be a tight fibrous band connecting the spine to the rib that causes compression. […] Trauma. A traumatic event, such as a car accident, can cause internal changes that then compress the nerves in the thoracic outlet. The onset of symptoms related to a traumatic accident often is delayed.

• #3 Anatomy and Pathogenesis of Vascular Thoracic Outlet Syndrome

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9981236/

  The current literature review article describes the anatomy and pathogenesis of the vascular nature of thoracic outlet syndrome (TOS), as well as gathers the latest and most important information concerning its diagnostic methods and treatment. […] Thoracic outlet syndrome (TOS) is characterized by neurological and vascular symptoms. The condition is caused by the compression of the subclavian vessels and brachial plexus (BP) as they exit the thoracic chest. […] TOS is classified into three distinct forms, according to its pathophysiology: the neurogenic thoracic outlet syndrome (NTOS) after the BP compression, the arterial thoracic outlet syndrome (ATOS) after the subclavian artery (SCA) compression, and the venous thoracic outlet syndrome (VTOS) after the subclavian vein (SCV) compression.

• #3 Anatomy and Pathogenesis of Vascular Thoracic Outlet Syndrome

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9981236/

  TOS can be caused by a plethora of mechanisms, including trauma, anatomical alterations, and repetitive movements. […] TO trauma can easily cause hemorrhage, hematoma, or an injured structure that may compress nerves, veins, or arteries. […] Moreover, repetitive motions can induce muscle hypertrophy. Hypertrophy leads to compression of the structure and, as a result, the BP, SCV, or SCA may be injured. […] Cervical or anomalous first ribs that are fused with the second rib can alter the TO dimensions, and therefore, make the space contract and extend. […] The VTOS constitutes 3-4% of the incidents. This form causes SCV compression and, therefore, thrombosis. […] The ATOS constitutes only 1-2% of the occasions. The continuous SCA friction and the pulsation of the underlying first rib may cause fibrosis, narrowing of the artery, aneurysms, and thrombosis.

• #3 Anatomy and Pathogenesis of Vascular Thoracic Outlet Syndrome

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9981236/

  Symptoms that indicate a vascular TOS are not easily identified. ATOS is generally asymptomatic and the symptoms begin to develop after embolization has occurred. […] ATOS can be subcategorized based on the way of its pathogenesis in acute thrombosis, chronic stenosis, non-thrombotic ischemia, distal embolization, and total occlusion. […] The main symptoms include claudication and pain during the arms activity, which slowly subsides after the end of the movement. […] If they remain untreated, they can lead to as far as gangrene. […] VTOS (Paget-von Schroetter syndrome or effort thrombosis) is more common than ATOS. […] VTOS is usually prompted by repetitive arm movement and/or bone abnormalities. […] The first indication of the acute type is purple-red discoloration of the swollen extremity, and it can lead to visibly dilated superficial veins across the upper body.

• #4 Overview of thoracic outlet syndromes – UpToDate

  https://www.uptodate.com/contents/overview-of-thoracic-outlet-syndromes

  Thoracic outlet syndrome (TOS) refers to a constellation of signs and symptoms that arise from compression of the neurovascular bundle by various structures in the area just above the first rib and behind the clavicle, within the confined space of the thoracic outlet. […] Distinct terms are used to describe the predominantly affected structure, including neurogenic (nTOS) from brachial plexus compression, venous (vTOS) from subclavian vein compression, and arterial (aTOS) from subclavian artery compression. […] Compression of the brachial plexus leads to upper extremity numbness, dysesthesia, and weakness; venous compression may cause deep vein thrombosis and extremity swelling, and arterial compression can lead to distal thromboembolism, arm pain with exertion („claudication”), or acute arterial thrombosis. […] An overview of the anatomy, pathogenesis, clinical evaluation, and approach to the management of the thoracic outlet syndromes will be reviewed with an emphasis on the features that distinguish these syndromes from one another.

• #5 Thoracic Outlet Syndrome: A Narrative Review

  https://www.mdpi.com/2077-0383/10/5/962

  There are many potential causes of TOS, ranging from congenital anomalies to repetitive motion injuries, all of which result in compression of the neurovascular bundle traversing the thoracic outlet. Nearly 70% of cases are related to soft tissue etiologies (such as scalene hypertrophy, regional tumors, or a muscular variation such as the scalenus minimus muscle), with the remaining 30% related to bone abnormalities such as cervical ribs or joint injury with resulting malunion. Additionally, TOS etiologies may be divided into traumatic and nontraumatic causes. A majority of nTOS cases are preceded by neck trauma due to either acute neck hyperextension or midshaft clavicular fracture sustained during motor vehicle accidents. […] When discussing pertinent TOS anatomy, three spaces of frequent neurovasculature compression are the scalene triangle, costoclavicular space, and subcoracoid space. The most medial of the three is the scalene triangle, which is bounded anteriorly by the anterior scalene muscle, posteriorly by the middle scalene muscle, and inferiorly by the first rib. The scalene triangle contains the trunks of the brachial plexus and the subclavian artery, while the subclavian vein passes beneath the anterior scalene, avoiding the compartment altogether. Structures within the scalene triangle are often compressed by anatomic variations of the scalene muscles, the presence of the scalenus minimus muscle, or osseous abnormalities such as the presence of a cervical rib.

• #5 Thoracic Outlet Syndrome: A Narrative Review

  https://www.mdpi.com/2077-0383/10/5/962

  The constellation of symptoms seen in true nTOS is caused by compression or irritation of brachial plexus nerves. Pain, paresthesia, and/or weakness in the distribution of affected nerve roots are the hallmarks of nTOS presentation. Compression of the lower plexus (C7-T1) elicits pain of the medial arm, forearm, and hand, paresthesia of the fourth and fifth digits, and hand weakness or loss of dexterity. Similarly, compression of the upper plexus (C5-C7) results in pain in the neck, shoulder, chest, and supraclavicular region, along with arm weakness and paresthesia of the first three digits. […] As mentioned above, nTOS can be subdivided into true or disputed nTOS, and is categorized as true nTOS with the presence of objective diagnostic abnormalities. True nTOS presents very rarely and is classically a unilateral condition in female patients, while disputed nTOS makes up for 95–99% of all nTOS cases, is often bilateral, and does not feature a classic syndromic vignette as the other types of TOS do. […] While many TOS treatment options exist, the optimal therapy regimen remains unclear. This review aims to provide physicians a brief summary of both pathogenesis, diagnosis, and treatment of TOS, as well as significant findings in the recent literature.

• #6

  https://www.orthobullets.com/shoulder-and-elbow/3064/thoracic-outlet-syndrome

  Thoracic outlet syndrome is a neurovascular disorder resulting from compression of the brachial plexus and/or subclavian vessels in the interval between the neck and axilla. […] most cases are thought to stem from anatomic predisposition with superimposed neck trauma (acute or chronic repetitive stress) […] anatomically, can be organized into soft tissue (70%) and osseous (30%) abnormalities. […] soft tissue tumors […] Pancoast tumor […] tumor of the pulmonary apex. […] cervical rib […] arise from the 7th cervical vertebra. […] chronic overuse […] repetitive shoulder use […] vascular […] repetitive compression over time can result vessel damage […] limb-threatening ischemia.

• #7 What is Thoracic Outlet Syndrome: An Overview by Dr. Aghayev

  https://kamranaghayev.com/what-is-thoracic-outlet-syndrome/

  The brachial plexus and subclavian artery pass through a narrow anatomical window called the scalene triangle. […] Thoracic outlet syndrome is a term that describes the site (location) of the disease rather than the cause. […] There are several conditions predisposing to thoracic outlet syndrome. […] Cervical accessory ribs in people with thoracic outlet syndrome is 29% approximately 25 times more than in the general population. […] The first rib is a curved flat bone lying between the first thoracic vertebra and sternum. Anomalous, broken, or misplaced first ribs can cause TOS by stretching or compressing the neuro-vascular bundle. […] Fibromuscular soft tissue bands constitute a significant portion of TOS cases. […] Hypertrophic muscles also may cause neurovascular compression.

• #7 What is Thoracic Outlet Syndrome: An Overview by Dr. Aghayev

  https://kamranaghayev.com/what-is-thoracic-outlet-syndrome/

  The neuro-vascular bundle passes through this gap just above the first rib and below the clavicle. However, with arm abduction, the costo-clavicular gap may become very narrow due to the movement of the scapula. […] Occasionally, blood vessels branching from subclavian vessels may loop around the brachial plexus and cause compression. […] Arterio-venous fistula provides easy vascular access in hemodialysis patients. However, the major problem is increased blood flow and turbulence in the subclavian vein.

• #8 Thoracic Outlet Syndrome Video: TOS Explained by Dr. Aghayev

  https://kamranaghayev.com/tos-explained-video-transcript/

  Venous TOS, or vTOS, is a less common variant, comprising about 15% to 20% of cases. The subclavian vein is compressed and symptoms develop due to insufficient blood return from the arm. […] Arterial TOS, or aTOS, is the least common form, with approximately 1% to 2% of all TOS cases. The subclavian artery is compressed, which leads to insufficient blood flow to the affected arm. […] Multiple causes have been identified. […] Scientific evidence shows that the cause is skeletal and muscular abnormalities. […] A cervical accessory rib is usually part of the abnormality. […] These ribs extend from the 7th cervical vertebra, above the first rib. […] The first rib is a C-shaped flat bone. It forms the most part of the thoracic outlet area and is the main culprit for TOS. […] The problem may come from the shape or the position of the first rib.

• #8 Thoracic Outlet Syndrome Video: TOS Explained by Dr. Aghayev

  https://kamranaghayev.com/tos-explained-video-transcript/

  Fibromuscular soft tissue bands constitute a significant portion of TOS cases. […] Hypertrophic muscles may also cause compression in the thoracic outlet area. […] The nutcracker mechanism is the leading cause of Thoracic Outlet Syndrome. […] Another less known mechanism for TOS comes from subclavian artery or vein branches. […] Therapeutic arteriovenous fistula is a very common method used for easy vascular access in hemodialysis patients. […] However, one of the major shortcomings is increased blood flow and turbulence in the subclavian vein. […] Since the cause of TOS is anatomical, at least in the majority of cases, surgery is the only way to permanently treat the disease. […] To achieve decompression, the surgeon must remove the first rib, find the nerves, artery, and vein, and free them up by cutting all muscular and fibrotic bands.

• #9 Thoracic Outlet Compression Syndromes (TOS) – Neurologic Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/neurologic-disorders/peripheral-nervous-system-and-motor-unit-disorders/thoracic-outlet-compression-syndromes-tos

  Pathogenesis is often unknown but sometimes involves compression of the lower trunk of the brachial plexus (and perhaps the subclavian vessels) as these structures traverse the thoracic outlet below the scalene muscles and over the 1st rib, before they enter the axilla, but this involvement is unclear. […] Compression may be caused by A cervical rib […] An abnormal 1st thoracic rib […] Abnormal insertion or position of the scalene muscles […] A malunited clavicle fracture.

• #10 Anatomy – Thoracic outlet syndrome (TOS) – Left transaxillary first rib resection (TFRR) – Vascular surgery

  https://www.webop.com/vascular-surgery/supraaortic-procedures/thoracic-outlet-syndrome-tos-left-transaxillary-first-rib-resection-tfrr-vascular-surgery/anatomy

  This accessory muscle arises from the transverse process of the 7th cervical vertebra, travels between the brachial plexus and subclavian artery and inserts on the first rib or the pleural dome, thus constricting the scalene gap and also impeding access to it. […] Other anatomic variants include, for example, steepening of the first rib or a rudimentary first rib, hypertrophy of the scalene muscles, as well as variants of their insertions on the first rib, resulting in a narrowed angle between the anterior scalene muscle, first rib and clavicle, thereby displacing and compressing the neurovascular bundle.

• #11 Epidemiology and pathogenesis of thoracic outlet syndrome

  https://sciendo.com/article/10.1515/cipms-2015-0036

  The superior thoracic aperture is a place particularly vulnerable to the occurrence of tissue conflict and the development of a number of neurovascular changes carrying a risk of upper limb dysfunction. […] The triggering factor in this case is the pressure on the nerve vascular elements brought about by too large muscles of the chest and neck, clavicle fracture and dislocation of the upper ribs, anomalies in the form of ribs, in the neck, or by apex of the lung tumors. […] Each anatomical anomaly may be a cause of a number of lesions and lead to the development of the disease. […] Due to the nature of the oppressed structures, there are two basic groups: neurogenic and vascular. […] The most common variant giving clinical symptoms is neurogenic thoracic outlet syndrome. […] However, the vascular variant, and especially arterial sub-variant, is very dangerous because it can give complications even in the form of aneurysms, and even upper limb ischemia.

• #12

  https://link.springer.com/article/10.1007/s40122-019-0124-2

  Arterial TOS is by far the most rarely observed, occurring in 2-5% of TOS cases. […] Subclavian artery compression within the scalene triangle may be caused by an anomalous first rib, which ultimately developing an aneurysm distally. […] Though inherently distinct etiologically, the three forms of TOS share a fundamental mechanism of extrinsic neurovascular compression that ultimately produces severe pain and disability.

• #12

  https://link.springer.com/article/10.1007/s40122-019-0124-2

  Repetitive motions can lead to muscle hypertrophy that contributes to compression. […] Myriad anatomic variations incite TOS. […] One such variation, the presence of a cervical rib, bears an estimated prevalence of 12% of the general population but remains asymptomatic for most people. […] Malignancy causing compression is another well-documented etiology of TOS. […] Neurogenic TOS is caused by compression of the C5 through T1 brachial plexus nerve roots and comprises up to 90% of total TOS cases. […] Compression of the nerve roots most often occurs within the scalene triangle but can also occur in the subarachnoid space as the nerve roots traverse beneath the pectoralis minor tendon. […] Venous TOS, also referred to as Pagetvon Schroetter syndrome, comprises 10-15% of cases, and is caused by subclavian compression within the costoclavicular space.

• #12

  https://link.springer.com/article/10.1007/s40122-019-0124-2

  Thoracic outlet syndrome (TOS) constitutes a group of diverse disorders that result in compression of the neurovascular bundle exiting the thoracic outlet. […] Compression of this area causes a constellation of distinct symptoms, which can include upper extremity pallor, paresthesia, weakness, muscle atrophy, and pain. […] TOS classifications are based on the pathophysiology of symptoms with subgroups consisting of neurogenic (nTOS), venous (vTOS), and arterial (aTOS) etiologies. […] Numerous mechanisms elicit the characteristic pathology of TOS, including trauma, repetitive motions, and anatomic variations. […] Traumatic events are typically high velocity, most often in the setting of a motor vehicle accident. […] Whiplash injuries exhibit a known association with TOS, most often of the neurogenic subtype; patients with a cervical rib are reportedly predisposed to this outcome.

• #13 Overview of thoracic outlet syndromes – UpToDate

  https://www.uptodate.com/contents/overview-of-thoracic-outlet-syndromes/print

  Thoracic outlet syndrome (TOS) refers to a constellation of signs and symptoms that arise from compression of the neurovascular bundle by various structures in the area just above the first rib and behind the clavicle, within the confined space of the thoracic outlet. […] The term „thoracic outlet syndrome” was coined to collectively encompass the spectrum of syndromes related to the general region of the thoracic outlet. […] Distinct terms are used to describe the predominantly affected structure, including neurogenic (nTOS) from brachial plexus compression, venous (vTOS) from subclavian vein compression, and arterial (aTOS) from subclavian artery compression. […] Neurogenic TOS accounts for greater than 95 percent of cases of thoracic outlet syndrome, whereas vTOS accounts for 3 percent and aTOS accounts for 1 percent of cases.

• #14

  https://www.alliedacademies.org/articles/vascular-thoracic-outlet-syndrome.html

  On the other hand, occlusion of the subclavian vein, completely or partially, is the primary mechanism of venous TOS. […] Chronic compression and irritation of the vessel walls can predispose or cause stasis, mainly by impairing the clearance of activated coagulation factors; intimal damage, through exposure of tissue factor to the blood coagulation system; and/or hypercoagulability (Virchow triad), resulting in formation of an intraluminal thrombus, which causes the lumen to become narrowed or entirely occluded, and end with primary venous thrombosis. […] Bony abnormality represents the most frequent cause of arterial compression in the thoracic outlet. Among arterial TOS patients, 88% presented an osseous abnormality, most of which were cervical ribs. […] The result is soft tissue hypertrophy and cramping in the space of the bony outlet, or can lead to direct arterial injury through repetitive motion.

• #14

  https://www.alliedacademies.org/articles/vascular-thoracic-outlet-syndrome.html

  Thoracic outlet syndrome (TOS) is a collection of upper extremity symptoms that result from compression of the neurovascular bundle by various structures in the area just above the first rib and behind the clavicle. […] The main pathophysiology is based on a mechanism of chronic compression over the subclavian artery or vein and then stenosis, which results in further intimal injury with fibrosis, thickening, and arterial luminal narrowing or complete or partial venous occlusion and thrombosis. […] For arterial TOS, the essential mechanism is chronic compression over the subclavian artery, and then stenosis. Furthermore, this chronic compression can result in intimal injury with fibrosis, thickening of the wall, and, eventually, luminal narrowing. […] This disruption precipitates platelet deposition and initiates formation of a thrombus after activation of collagen and tissue factor that play an important role in thrombus formation by activation and accumulation of platelets and generation of thrombin.

• #15 Thoracic outlet syndrome – Wikipedia

  https://en.wikipedia.org/wiki/Thoracic_outlet_syndrome

  Thoracic outlet syndrome (TOS) is a condition in which there is compression of the nerves, arteries, or veins in the superior thoracic aperture, the passageway from the lower neck to the armpit, also known as the thoracic outlet. There are three main types: neurogenic, venous, and arterial. The neurogenic type is the most common and presents with pain, weakness, paraesthesia, and occasionally loss of muscle at the base of the thumb. The venous type results in swelling, pain, and possibly a bluish coloration of the arm. The arterial type results in pain, coldness, and pallor of the arm. […] TOS may result from trauma, repetitive arm movements, tumors, pregnancy, or anatomical variations such as a cervical rib. […] Repetitive motions can cause enlargement of muscles which causes compression of veins. Besides, overuse injury of the upper limbs causes swellings, small bleeding, and subsequent fibrosis which would cause the thrombosis of the subclavian vein, leading to Paget-Schroetter disease or effort-induced thrombosis.

• #15 Thoracic outlet syndrome – Wikipedia

  https://en.wikipedia.org/wiki/Thoracic_outlet_syndrome

  TOS can also lead to eye problems and vision loss as a circumstance of vertebral artery compression. Although very rare, if compression of the brain stem is also involved in an individual presentation of TOS, transient blindness may occur while the head is held in certain positions. […] TOS has similar symptoms to pectoralis minor syndrome (PMS), which usually results from compression of the braxial plexus beneath the pectoralis minor muscle (while neurogenic TOS is caused by compression of the same nerves above the clavicle). Unlike TOS there is typically few headaches or neck pain in patients with PMS only, instead with pain in the chest area. […] Initially, it was believed that 95 percent of patients with TOS had nerve compression in the scalene area, but in the twenty-first century it is now recognized that the majority have nerve compression under the pectoralis minor, either by itself or in addition to the scalene area.

• #16 Upper extremity deep vein thrombosis: pathogenesis and treatment | Pukacki | Acta Angiologica

  https://journals.viamedica.pl/acta_angiologica/article/view/63752

  Upper extremity deep vein thrombosis (UEDVT) may be the first manifestation of venous thoracic outlet syndrome(VTOS). […] The clinical findings depend on the degree of obstruction of the subclavian vein. […] Correct diagnosis aided by various imaging modalities as well as rapid initiation of local thrombolytic therapy, surgical decompression of the thoracic outlet (when indications are present), and the immediate initiation of anticoagulation therapy aim at successfully restoring the patients quality of life.

• #17 Thoracic Outlet Syndrome | Musculoskeletal Key

  https://musculoskeletalkey.com/thoracic-outlet-syndrome/

  The third location is a region below the coracoid process just under the pectoralis minor tendon. […] It is believed that compression through this space can occur via mechanisms associated with arm abduction, in which the neurovascular bundle gets stressed underneath a taut pectoralis minor tendon. […] Arterial TOS is reported to account for 1% to 5% of all TOS cases. […] In severe arterial TOS, vessel damage could result in poststenotic aneurysm or distal embolic occlusions causing advanced ischemic damage to the extremity. […] Venous TOS represents 2% to 3% of all forms of TOS. […] Serious complications of advanced venous thrombosis are pulmonary embolus, severe pain, and edema. […] Accounting for 90% to 97% of TOS cases, the neurogenic type has been subdivided into true neurogenic TOS (N-TOS), and more common disputed neurogenic TOS. […] This myriad of symptoms is thought to be a result of the variability between upper versus lower compression sites of the brachial plexus.

• #18 Thoracic Outlet Syndrome Treatment

  https://nevadanervesurgery.org/conditions-we-treat/thoracic-outlet-syndrome-treatment/

  Neurogenic TOS is most commonly arises following some type of trauma. Any type of injury mechanism which causes rapid widening of the angle between the neck and shoulder, whiplash-type injuries to the neck, blunt trauma to the base of the neck/collar bone area, or traction to the arm can lead to neurogenic TOS. […] These types of injury mechanisms can cause trauma to the scalene muscles or the brachial plexus (nerves) itself. Damage to these structures can produce bleeding, swelling, and subsequent scarring and contracture or shrinking of the tissue around the nerves leading to compression and tethering. Ultimately this leaves the brachial plexus in a condition where it is under pressure and unable to glide or move through the surrounding tissue like its supposed to. […] The presence of a cervical rib, congenital or acquired deformity of the first rib, or unusual fibrous bands or configurations of the anterior and middle scalene anatomy can also significantly increase the risk of developing neurogenic TOS. […] Venous or arterial TOS are almost always due to some type of underlying congenital deformity of the first rib, the presence of a cervical rib, or anomalous fibrous bands which result in an unusually tight space around the vein or artery leading to compression.

• #19 Thoracic Outlet Syndrome | PM&R KnowledgeNow

  https://now.aapmr.org/thoracic-outlet-syndrome/

  Repetitive trauma to the neurovascular bundle at the thoracic inlet may lead to TOS, with the lower trunk or medial cord of the brachial plexus most affected.1 Functional thoracic outlet syndrome has been associated in case reports with postural deviation, including increased kyphosis exacerbating compression at the thoracic inlet. Repetitive shoulder use and above-shoulder athletic endeavors (swimming, throwing) may increase injury risk.6, 27-29 Nonspecific thoracic outlet syndrome may be seen secondary to kyphotic posture, tight pectoralis and latissimus dorsi muscles.

• #20 Thoracic Outlet Syndrome | Frankel Cardiovascular Center | Michigan Medicine

  https://www.umcvc.org/conditions-treatments/thoracic-outlet-syndrome

  Thoracic outlet syndrome (TOS) describes a group of disorders involving compression of the nerves or blood vessels between the muscles of the neck and shoulder or between the first rib and collarbone (clavicle). […] TOS often afflicts otherwise healthy, young, active individuals and symptoms are specific to nerve compression (neurogenic or NTOS), arterial compression (ATOS) or venous compression (VTOS). […] This is the most common form of TOS and is due to compression of the nerves between the first rib, collarbone (clavicle) and scalene muscles. NTOS can result from a combination of a congenitally narrow thoracic outlet with trauma (for example, falls, motor vehicle accidents, first rib fractures) or repetitive trauma from work-related activity (for example, typing, administrative work or manual labor) or recreational activities (baseball, football, swimming, volleyball).

• #21 Thoracic Outlet Syndrome: Practice Essentials, Etiology, Epidemiology

  https://emedicine.medscape.com/article/96412-overview

  Interestingly, multiple points of compression may be present as the peripheral nerves descend from the thoracic outlet to the hand (simultaneous thoracic outlet syndrome and ulnar nerve compression at the elbow or carpal tunnel syndrome in the wrist). This has been referred to as double- or multiple-crush syndrome.

• #22 Does thoracic outlet syndrome cause cerebrovascular hyperperfusion? – Diagnostic markers for occult craniovascular congestion, Larsen et al. 2019 | Science for ME

  https://www.s4me.info/threads/does-thoracic-outlet-syndrome-cause-cerebrovascular-hyperperfusion-diagnostic-markers-for-occult-craniovascular-congestion-larsen-et-al-2019.19720/

  Thoracic outlet syndrome (TOS) is attributed to the brachial plexus and subclavian artery being compressed in the interscalene triangle, costoclavicular or subpectoral passages. […] We postulate that the compression imposed on the distal subclavian artery in TOS not only inhibits some blood from entering the brachium, but that the obstructed blood reverts toward the head, resulting in, to some extent, continuous TOS-induced cerebrovascular hyperperfusion (CVH). […] TOS CVH often causes pronounced fatigue, and is a common co-finding in patients with myalgic encephalomyelitis (ME) / chronic fatigue syndrome.

• #23 How to truly identify and treat thoracic outlet syndrome (TOS) – MSK Neurology

  https://mskneurology.com/how-truly-treat-thoracic-outlet-syndrome/

  Compression directly to the brachial plexus is the most common driver of thoracic outlet syndrome. […] It has infact been estimated that approximately 95% of the thoracic outlet syndrome cases are related to neurogenic symptoms (Wilbourn et al., 1990). […] Research has demonstrated a connection between compression of the subclavian artery and compromise of the vertebral artery, an artery that supplies the posterior brain with blood. […] Thoracic Outlet Syndrome (TOS) causes dizziness because of positional compression of the vertebral artery with resultant symptoms of vertebrobasilary insufficiency. […] The cases of 17 patients with vertigo, tinnitus, deafness, supraclavicular bruit, and a diminished radial pulse are reported. […] Compression of 7,C8,and T1 nerves fibers is responsible for the neck pain. […] It is also noteworthy that the hypertrophied and contracted anterior scalenus muscle exerts a strong although intermittent compression of the vertebral artery, causing in severe TOS diverse symptoms that are very characteristic of vertebrobasilary insufficiency.

• #24 Posterior cerebral artery stroke by reverse flow embolism in thoracic outlet syndrome – a case report | BMC Neurology | Full Text

  https://bmcneurol.biomedcentral.com/articles/10.1186/s12883-020-01797-y

  Arterial thoracic outlet syndrome is a rare condition characterized by a subclavian artery pathology associated with a bone abnormality. It is rarely associated with thromboembolic stroke. The mechanism of cerebral embolism associated with thoracic outlet syndrome have rarely been demonstrated. […] Cerebral embolism is a rare but known complication of arterial TOS. Two mechanisms are proposed (in case of native arteries without chronic occlusion of the SCA): either retrograde spreading of a thrombus or backward embolism within the SCA. […] The mechanism by which cerebral stroke is associated with arterial TOS has yet to be fully understood. This complication of arterial TOS has never been systematically studied, therefore its incidence is not known. […] We report the case of a patient whose doppler analysis shows that the retrograde flow embolism mechanism is both possible (amplitude of the reflux distance between the aneurysm and the right vertebral artery ostium) and very likely (mobile thrombus in the post-stenotic aneurysmal sac).

• #24 Posterior cerebral artery stroke by reverse flow embolism in thoracic outlet syndrome – a case report | BMC Neurology | Full Text

  https://bmcneurol.biomedcentral.com/articles/10.1186/s12883-020-01797-y

  The first step of these embolic strokes is the SCA compression, intimal lesion leading to the formation of a thrombus. It is an acquired media disease secondary to extrinsic (bone compression) and intrinsic (turbulent / post-stenotic turbulent / non-linear flow) mechanical stress. The appearance of the thrombus can be explained by: intimal lesions or a low velocity flow in the bulge of the aneurysm sac. […] Two mechanisms are proposed. First, a retrograde propagation of the thrombus to the vertebral or common carotid arteries. Vascular imaging has shown in some cases of arterial TOS associated strokes an extended thrombus in the brachiocephalic artery. The second mechanism is a transient retrograde flow and embolism from the SCA post stenotic aneurysm to the vertebral artery. This mechanism has been highly suspected in three other cases. […] Our case, with an extensive ultrasound and doppler workup, advocates for a retrograde embolism. It is the first case to actually measure flux durations, distances and velocities, in order to prove that this mechanism is possible.

• #25

  https://crimsonpublishers.com/nrs/fulltext/NRS.000755.php

  Examination of the medial aspect of the resected first ribs in patients with PSS has demonstrated the presence of a congenitally malformed bony tubercle which forms a tighter and wider joint at the junction of the first rib and the sternum. […] It has been observed that the wider and less mobile cost-sternal joint locks the medial aspect of the first rib into place and results in extrinsic compression by the boney tubercle onto the Subclavian Vein (SV) at its junction with the innominate vein. […] Furthermore, these studies have demonstrated that the SV compression increases with elevation of the arm above the shoulder. […] Therefore, it has been hypothesized that in a subset of patients, NTOS may be the manifestation of compression of the subclavian vein, and venous congestion resulting in venous ischemia of the upper extremity nerves which lead to diffuse neurologic symptoms unrelated to nerve compression. […] Given the fact that the subclavian vein has an average diameter of approximately 1cm in its position over the first rib, it was concluded that the tubercle compressed the subclavian vein at rest, and significantly occluded the vein with extension of the arm above the shoulder. […] Therefore, compression of the SV at its junction with the innominate vein may result in elevation of venous pressure, a decrease in arterial flow, and relative ischemia of the nerves of the upper extremity. […] It is suggested that these conditions may best be classified as subclavian vein compression syndrome.

• #26 (PDF) Reevaluating the Pathogenesis and Classification of Thoracic Outlet Syndrome

  https://www.academia.edu/82669054/Reevaluating_the_Pathogenesis_and_Classification_of_Thoracic_Outlet_Syndrome

  Therefore, it has been hypothesized that in a subset of patients, NTOS may be the manifestation of compression of the subclavian vein, and venous congestion resulting in venous ischemia of the upper extremity nerves which lead to diffuse neurologic symptoms unrelated to nerve compression. […] The majority of cases result from anatomical distortion at the interscalene triangle. […] The aetiology of neurogenic TOS is multifactorial, with bony tissue abnormalities and soft-tissue abnormalities described as definite contributors to the syndrome. These abnormalities contribute to the syndrome by altering the space within which the brachial plexus trunks run.

• #27 Thoracic Outlet Syndrome | SpringerLink

  https://link.springer.com/chapter/10.1007/978-3-031-44645-0_24

  Thoracic outlet syndrome (TOS) is the constellation of symptoms caused by compression of neurovascular structures in the thoracic outlet. TOS can be divided into three subgroups depending on the compressed structure: arterial TOS (aTOS), neurogenic TOS (nTOS), and venous TOS (vTOS). Trauma, repetitive overhead motions, and bony abnormalities are the most common predisposing risk factors, though a number of different etiologies can cause TOS. […] Initial treatment for nTOS is conservative, followed by surgical decompression for refractory disease. Patients with vTOS or aTOS who are good surgical candidates are recommended for surgical decompression. The procedure for surgical decompression is a first-rib resection and scalenectomy.

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