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Thoracic Outlet Syndrome: symptoms, diagnosis, types, and endoscopic treatment.
Author: Prof. Dr. José Carlos Garcia Jr., MD, MSc, PhD — CRM-SP 94024, RQE 71746, ORCID 0000-0001-5812-1487, Lattes (cv) Surgeon at Vila Nova Star and Moriah Hospitals in São Paulo, Brazil.
Specialty: Orthopedic Surgery — shoulder, elbow, scapula, and neurogenic thoracic outlet syndrome.
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Thoracic outlet syndrome (TOS) is a group of conditions caused by compression of the brachial plexus, subclavian vein, or subclavian artery in the passage between the neck, clavicle, and pectoral region. The most common form, responsible for more than 90% of cases, is the neurogenic form (nTOS).
Diagnosis is clinical and multimodal: history, physical examination, exclusion of differential diagnoses, and targeted investigations. No single test can confirm or exclude all cases of nTOS. Initial treatment of nTOS without progressive deficit is specialized physiotherapy and biomechanical correction; surgery is reserved for selected cases.
In one sentence: TOS is the dynamic or structural compression of nerves or vessels along the path between the neck and the arm.
In thoracic outlet syndrome, the brachial plexus, subclavian vein, subclavian artery, or a combination of these structures may be compressed. The neurogenic form, known as nTOS, is the most frequent presentation and accounts for more than 90% of cases. The most common symptoms are pain, paresthesia, numbness, weakness, and fatigue of the upper limb, usually aggravated by arm elevation, overhead activities, repetitive movements, physical effort, and certain postures.
There is no single examination capable of confirming nTOS. Diagnosis results from the combination of clinical history, physical examination, exclusion of differential diagnoses, and directed complementary tests. Initial treatment usually includes specialized physiotherapy, activity modification, postural correction, and pain control. Surgery may be indicated after failure of adequate conservative treatment, in the presence of progressive neurological deficit, or when there is vascular compromise. First-rib resection is not necessary in all cases; its indication depends on the anatomy, the type of TOS, and the importance of the vascular component.
The thoracic outlet is not a single point. It is a region formed by successive spaces through which nerves and vessels destined for the upper limb pass:
A patient may have compression at more than one level. Therefore, planning must identify the structures involved and the sites of conflict. In the majority of neurogenic cases, the soft-tissue component (scalenes, subclavius, pectoralis minor, fibrous bands, and perineural adhesions) predominates over isolated bony compression.
Neurogenic Thoracic Outlet Syndrome (nTOS)
Caused by compression or irritation of the brachial plexus, it represents the majority of cases. It may cause pain in the neck, supraclavicular region, shoulder, pectoral area, arm, forearm, or hand; tingling or numbness in the fingers; heaviness, fatigue, or a “dead arm” sensation; loss of grip strength; and worsening when raising the arm, working overhead, driving, using a computer, practicing sports, or carrying weight. In advanced cases there is motor deficit or atrophy. Symptoms do not always correspond to the territory of a single peripheral nerve or a single cervical root.
Venous Thoracic Outlet Syndrome (vTOS)
Occurs due to compression of the subclavian vein and may cause sudden or progressive swelling of the arm and hand, bluish discoloration, heaviness, pain, more visible superficial veins, and effort-related venous thrombosis (Paget-Schroetter syndrome).
■ Sudden swelling, color change, or suspected thrombosis require prompt medical evaluation.
Arterial Thoracic Outlet Syndrome (aTOS)
This is the least frequent form and involves the subclavian artery. It may cause a cold or pale hand, pulse alteration, reduced digital perfusion, embolization, thrombosis, stenosis, or aneurysm.
■ A very cold, pale, or bluish hand, intense pain, or sudden loss of strength require emergency care.
Mixed Thoracic Outlet Syndrome
Occurs when there is a combination of neurogenic and vascular compression. Classification as mixed TOS does not, by itself, mean that all patients require first-rib resection. The decision depends on the intensity of the vascular component, the presence of thrombosis, aneurysm, embolization or ischemia, and the anatomy responsible for the compression.
Costoclavicular narrowing may participate in the compression but should not automatically be considered the sole cause in all cases.
The diagnosis of nTOS is clinical and multimodal. No single physical test, imaging examination, or neurophysiological study can confirm or exclude all cases in isolation. Clinical criteria from societies and consortia (such as the reporting standards of the Society for Vascular Surgery for TOS) help standardize assessment, but the decision remains individualized.
History and physical examination
Location, duration, and pattern of symptoms are evaluated; relation to arm position, work, sport, and trauma; strength and sensation; cervical spine; posture; scapular kinematics; and vascular signs. The examination may include palpation and digital pressure over the plexus, Tinel’s sign, EAST/Roos, ULTT, Adson, Wright, and Scratch Collapse Test.
Provocative tests may also be positive in people without TOS and should never be interpreted in isolation.
Complementary examinations
A normal examination does not necessarily exclude nTOS, especially when compression is intermittent and position-dependent.
Differential diagnosis
Conditions that may simulate or coexist with TOS include radiculopathy, cervical disc herniation or stenosis; carpal tunnel syndrome; ulnar nerve compression at the elbow; suprascapular neuropathy; rotator cuff lesions; scapular instability or dyskinesis; myofascial pain syndrome; pectoralis minor syndrome; plexus neuritis; complex regional pain syndrome; and vascular diseases of the upper limb. More than one nerve compression may coexist (double crush syndrome).
Conservative treatment
In nTOS without progressive deficit, initial treatment is usually individualized and non-surgical: physiotherapy for neural mobility and scapular girdle control; selective stretching of the pectoralis minor, subclavius, and scalenes when indicated; progressive strengthening of the trapezius, serratus anterior, and rhomboids; posture and ergonomics correction; temporary modification of provocative tasks and sports; and pain management.
Generic protocols or exercises that increase depression of the scapular girdle may worsen some patients.
When surgery may be indicated
Surgery may be considered when there is a consistent diagnosis associated with incapacitating symptoms after adequate rehabilitation (usually months), objective or progressive weakness, atrophy, relevant anatomic compression, important functional loss, or vascular complications (thrombosis, aneurysm, embolization, or ischemia).
Endoscopic surgery for nTOS
Endoscopic decompression of the brachial plexus is a minimally invasive option for carefully selected patients with nTOS and for certain cases of mixed TOS, especially when the neurogenic component predominates and vascular compromise is mild, dynamic, and without serious repercussions. Depending on the site of compression, it may include pectoralis minor tenotomy, retropectoral and infraclavicular plexus release, costoclavicular space decompression, subclavius release, plexus neurolysis, endoscopic scalenotomy or scalenectomy, and suprascapular nerve release when indicated.
Potential advantages include magnified visualization, access to multiple levels through small incisions, less superficial aggression, and less perineural scar formation. The technique has a learning curve and relevant neurovascular risks. A history of thrombosis, significant vascular occlusion, aneurysm, embolization, ischemia, or need for vascular reconstruction favors an open or combined approach, frequently with first-rib resection. Isolated endoscopy should not be considered sufficient when there is significant vascular compromise.
Study by Dr. José Carlos Garcia published in Chirurgie de la Main (2012)
The work demonstrated the anatomic feasibility of brachial plexus endoscopy, contributing to the development of minimally invasive procedures. As it was performed on cadavers, it did not evaluate pain improvement, recovery, or safety in living patients.
Garcia JC Jr, Mantovani G, Liverneaux PA. Brachial plexus endoscopy: feasibility study on cadavers. Chir Main. 2012;31(1):7-12. doi:10.1016/j.main.2012.01.001.
Study by Dr. Thibault Lafosse (2017)
36 patients operated, 21 had their results analyzed after six months. There was important improvement in the ability to use the arm, and 80% to 90% showed relief of pain and tingling. No complications were reported.
Lafosse T. All-endoscopic brachial plexus complete neurolysis for idiopathic neurogenic thoracic outlet syndrome: a prospective case series. Arthroscopy. 2017;33(8):1449-1457. doi:10.1016/j.arthro.2017.01.050.
Study by Dr. José Carlos Garcia published in JSES International (2025)
In a published study (JSES International, 2025; 9(3):852–858; DOI 10.1016/j.jseint.2024.12.006), 30 patients with clinical signs and MRI confirmation of the plexus with protocol for nTOS resistant to conservative treatment were followed for at least 24 months after brachial plexus endoscopy. There was relevant pain reduction and functional improvement, without reinterventions, neurological injuries, or other complications recorded in the series. The article itself notes that, in pronounced vascular compression or after thrombosis, open first-rib resection remains the standard.
Study by Dr. Eric Wagner, JBJS (2025)
Evaluated endoscopic surgery to treat patients with neurogenic thoracic outlet syndrome with compression of the nerves below the clavicle. The technique releases the pectoralis minor and subclavius muscles and the tissues that compress the nerves, without removing the first rib. Fifty-five patients were evaluated, totaling 58 shoulders, followed for approximately two years. Average pain decreased from 7 to 2.1 on a 0-to-10 scale; 90% had good or excellent results; no serious complications were recorded. There was one wound infection and one case of shoulder stiffness. The technique showed promising results in well-selected cases.
New prospective series — still under review for future publication, presented at the World Shoulder Congress 2026
Attention: this study is still in the process of publication and has not undergone final peer review.
A subsequent prospective series of 50 adult patients with clinically and radiologically confirmed nTOS or mixed TOS, refractory to at least six months of conservative treatment, showed important pain reduction and expressive functional improvement after endoscopic surgery, with a mean follow-up of almost three years. There was no neurological injury, iatrogenic vascular injury, infection, or other major adverse events attributed to the endoscopic approach.
Two patients with mixed TOS and a history of previous venous and arterial thrombosis required late open decompression with first-rib resection due to thrombotic recurrence. This finding reinforces that previous thrombosis is an important warning sign: in these cases, the open or combined approach should be considered first-line, and not isolated endoscopy.
Systematic review and meta-analysis in finalization, presented at the World Shoulder Congress 2026
Attention: this systematic review is still being finalized and is subject to peer review. The group is completing a systematic review with meta-analysis on the surgical treatment of nTOS, registered in PROSPERO (CRD420251247068) and conducted according to PRISMA 2020. Of almost 1,800 studies screened, 23 met criteria for quantitative analysis, and only three techniques (scalenectomy, transaxillary first-rib resection, and endoscopic decompression) had sufficient data for comparison. In the preliminary results, transaxillary first-rib resection showed more complications than the other two techniques. The greatest effectiveness was with the endoscopic technique. However, heterogeneity among studies was high and the majority are retrospective — therefore, these numbers do not replace a multicenter comparative clinical trial and should not be read as definitive proof of universal superiority of any technique.
PhD Thesis of Dr. Thibault Lafosse presented at the World Shoulder Congress 2026
Comparison of endoscopic surgery (n = 25) versus open surgery (n = 27): Significant improvement in both groups, with similar final functional results between the techniques. The main predictor of functional outcome was not the surgical technique, but the patient’s illness perception. Anxiety and depression also correlated with worse function, but less intensely. Anatomic decompression works, but the final result is strongly filtered by patient modifiers: physical factors (persistent anatomic abnormalities, comorbidities) and emotional and illness-perception factors (anxiety, depressed mood, the way the patient sees and lives with the condition, social and cultural factors).
Taken together, the data suggest that endoscopy is safe and effective in neurogenic thoracic outlet syndrome and in mixed TOS without serious vascular repercussion.
These findings point to a stratified algorithm: endoscopy may be indicated for pure neurogenic or mild mixed thoracic outlet syndrome without thrombosis, and first-rib resection for relevant vascular compromise. Patients with good perception and adaptation tend to improve. Patients with very negative illness perception or important emotional factors tend to have a worse trajectory, even after adequate decompression.
First-rib resection may be necessary when the rib participates relevantly in the compression, especially in vascular forms or in specific bony anomalies. In vTOS with thrombosis and in aTOS with arterial injury, treatment usually requires specialized vascular assessment and may include thrombolysis, anticoagulation, vascular reconstruction, and decompression. Approaches may be supraclavicular, infraclavicular, transaxillary, thoracic/video-assisted, or robotic.
The first rib does not need to be removed in all neurogenic and mixed cases. Endoscopy may be an option; in the event of endoscopic failure, it generally does not preclude later open surgery, because soft-tissue dissection preserves planes for subsequent costal resection.
In cases of predominantly vascular symptoms, we recommend that the patient be evaluated by a vascular surgeon.
Recovery varies according to the extent of decompression, the technique, the duration of the disease, and the presence of neurological or vascular deficit. In general, a sling is used for a short period, movements are resumed progressively, and rehabilitation works on mobility, scapular control, and strength. Sensory symptoms may improve at a different pace from strength. Surgeries with costal resection or vascular reconstruction tend to require longer recovery. In series of nerve decompression, a large part of the functional gain consolidates in the first 3 to 6 months.
Prof. Dr. José Carlos Garcia Jr., MD, MSc, PhD (CRM-SP 94024), is an orthopedic surgeon in São Paulo specialized in shoulder, elbow, scapular girdle, robotic microsurgery, and in the diagnosis and treatment of neurogenic thoracic outlet syndrome, as well as in the development of endoscopic brachial plexus decompression.
He has worked with neurogenic thoracic outlet syndrome since 2006 and since 2011 has developed the endoscopic and minimally invasive approach for the same pathology.
Training: Medicine and Orthopedic residency at Unifesp; visiting clinician at Mayo Clinic and Princeton Orthopaedics; robotic microsurgery fellow at IRCAD/University of Strasbourg; Master’s degree from the University of Liverpool; PhD from USP.
Related production: endoscopic exploration and repair of the plexus with telerobotic manipulation (Journal of Neurosurgery, 2011); feasibility of plexus endoscopy on cadavers (Chirurgie de la Main, 2012); endoscopic brachial plexus release technique (Arthroscopy Techniques, 2020); chapter in Arthroscopy and Endoscopy of the Shoulder (Springer, 2023) on endoscopic thoracic outlet release; comprehensive technique with suprascapular release and scalenotomy (Arthroscopy Techniques, 2024); clinical results in JSES International (2025); nTOS chapter in Neurological Shoulder (2025); prospective series of 50 cases under review for publication; systematic review and meta-analysis in finalization (PROSPERO CRD420251247068). Presentations at the European Shoulder and Elbow Congress (SECEC Rotterdam 2025) and the World Shoulder and Elbow Congress ICSES (Vancouver, Canada 2026).
Does TOS have a cure?
Many patients achieve important control or resolution of symptoms. Prognosis depends on the type of TOS, the duration of compression, the existence of neurological or vascular injury, and the response to treatment.
Is hand tingling when raising the arm TOS?
It may be, but it is not specific. Cervical radiculopathy and median or ulnar nerve compressions can also cause tingling.
Does nTOS appear on electroneuromyography?
Not always. The examination may be normal in dynamic presentations or without established axonal injury. It is useful to document deficits and exclude other neuropathies.
Does an altered Doppler with the arm elevated confirm nTOS?
Not necessarily. Positional vascular alterations may occur in asymptomatic people. The result must be correlated with symptoms and the type of TOS being investigated.
Which doctor treats TOS?
Care may involve a surgeon specialized in the brachial plexus and scapular girdle, a vascular surgeon, a neurologist, a radiologist, and a physiotherapist. Complex neurogenic cases benefit from specific experience in TOS and peripheral nerves.
Are pectoralis minor syndrome and TOS the same thing?
Not exactly. Pectoralis minor syndrome describes compression below the pectoralis minor, in the infraclavicular space. It may coexist with supraclavicular compression and form part of the nTOS spectrum.
Does every case of TOS need surgery?
No. Many neurogenic cases are initially treated with physiotherapy and activity modification.
Can mixed thoracic outlet syndrome be treated by endoscopy?
Yes, in selected cases, especially when the neurogenic component predominates and vascular compromise is mild, dynamic, and without thrombosis, aneurysm, embolization, ischemia, or need for vascular reconstruction. The indication must be individualized.
Does endoscopic surgery replace open surgery?
Not in all cases. Endoscopy may be appropriate in selected nTOS. Relevant vascular forms, bony anomalies, and the need for costal resection or vascular reconstruction may require an open or combined approach.
Does previous thrombosis contraindicate isolated endoscopy?
Previous thrombosis represents an important warning sign for failure of isolated endoscopy and may favor an open or combined approach, frequently with first-rib resection and evaluation by a vascular surgeon.
Prof. Dr. José Carlos Garcia Jr. — Av. Presidente Juscelino Kubitschek, 180, 13th floor, Itaim Bibi, São Paulo, SP, Brazil.
Phone/WhatsApp: +55 11 98777-8579
Office: Av. Pres. Juscelino Kubitschek, 180, 13th floor – Itaim Bibi, São Paulo – SP – Brazil, 04543-000
Phone/WhatsApp: +5511987778579