Diagnosis and management of thoracic outlet syndrome in athletes.

The physical demands of sports can place patients at elevated risk of use-related pathologies, including thoracic outlet syndrome (TOS). Overhead athletes in particular (eg, baseball and football players, swimmers, divers, and weightlifters) often subject their subclavian vessels and brachial plexuses to repetitive trauma, resulting in venous effort thrombosis, arterial occlusions, brachial plexopathy, and more. This patient population is at higher risk for Paget-Schroetter syndrome, or effort thrombosis, although neurogenic TOS (nTOS) is still the predominant form of the disease among all groups. First-rib resection is almost always recommended for vascular TOS in a young, active population, although a surgical benefit for patients with nTOS is less clear. Practitioners specializing in upper extremity disorders should take care to differentiate TOS from other repetitive use-related disorders, including shoulder orthopedic injuries and nerve entrapments at other areas of the neck and arm, as TOS is usually a diagnosis of exclusion. For nTOS, physical therapy is a cornerstone of diagnosis, along with response to injections. Most patients first undergo some period of nonoperative management with intense physical therapy and training before proceeding with rib resection. It is particularly essential for ensuring that athletes can return to their baselines of flexibility, strength, and stamina in the upper extremity. Botulinum toxin and lidocaine injections in the anterior scalene muscle might predict which patients will likely benefit from first-rib resection. Athletes are usually satisfied with their decisions to undergo first-rib resection, although the risk of rare but potentially career- or life-threatening complications, such as brachial plexus injury or subclavian vessel injury, must be considered. Frequently, they are able to return to the same or a higher level of play after full recovery.

Malunion of a clavicle fracture caused thoracic outlet syndrome in a professional violinist.

Clavicle fractures are a common injury in adults. Most patients are treated non-operatively. In this case report, a 53-year-old professional violinist had a midt shaft clavicula fracture and was treated non-operatively. The fracture healed, but the patient developed thoracic outlet syndrome (TOS) and a venous thrombosis when playing violin. Surgery with restoration of the normal anatomy alleviated the symptoms and six months later she was symptom free and playing violin again. TOS is a rare complication to clavicle fractures and the treating doctors should be aware of the diagnosis.

Management of thoracic outlet syndrome in patients with hemodialysis access.

Patients with threatened arteriovenous access are often found to have central venous stenoses at the ipsilateral costoclavicular junction, which may be resistant to endovascular intervention. Stenoses in this location may not resolve unless surgical decompression of thoracic outlet is performed to relieve the extrinsic compression on the subclavian vein. The authors reviewed the management of dialysis patients with central venous lesions at the thoracic outlet, as well as the role of surgical decompression with first-rib resection or claviculectomy for salvage of threatened, ipsilateral dialysis access.

A review of arterial thoracic outlet syndrome.

Arterial thoracic outlet syndrome (TOS) is a condition in which anatomic abnormalities in the thoracic outlet cause compression of the subclavian or, less commonly, axillary artery. Patients are usually younger and typically have an anatomic abnormality causing the compression. The condition usually goes undiagnosed until patients present with signs of acute or chronic hand or arm ischemia. Workup of this condition includes a thorough history and physical examination; chest x-ray to identify potential anatomic abnormalities; and arterial imaging, such as computed tomographic angiography or duplex to identify arterial abnormalities. Patients will usually require operative intervention, given their symptomatic presentation. Intervention should always include decompression of the thoracic outlet with at least a first-rib resection and any other structures causing external compression. If the artery is identified to have intimal damage, mural thrombus, or is aneurysmal, then arterial reconstruction is warranted. Stenting should be avoided due to external compression. In patients with symptoms of embolization, a combination of embolectomy, lytic catheter placement, and/or therapeutic anticoagulation should be done. Typically, patients have excellent outcomes, with resolution of symptoms and high patency of the bypass graft, although patients with distal embolization may require finger amputation.

Thoracic outlet syndrome caused by superior mediastinal mass: A case report.

INTRODUCTION: Thoracic outlet syndrome (TOS) caused by superior mediastinal soft tissue mass has never been reported in the literature, the aim of this study is to discuss a case of TOS caused by a superior mediastinal mass in which the histopathological examinations of the mass showed vascular malformation. CASE REPORT: A 45-year-old female presented with left upper limb pain and numbness for three months, associated with swelling and attacks of shortness of breath. Imaging studies showed soft tissue mass involving the superior mediastinum. The condition of the patient deteriorated and the signs and symptoms of TOS became clearer, all provocative tests and nerve conduction studies were positive. The patient underwent thoracic outlet decompression. The patient did not respond and the symptoms deteriorated further. After a multidisciplinary board discussion, the patient was prepared for median sternotomy under general anesthesia. A total resection of the mass was done. The patient was totally relieved a few hours after the operation. DISCUSSION: The etiology of TOS can be multifaceted. Several factors contribute to its onset, and these can be categorized as congenital or acquired. Congenital causes include anatomical anomalies such as a cervical rib, or an elongated transverse process of the cervical vertebrae. These anatomical deviations can reduce the size of the thoracic outlet and make it prone to compression. CONCLUSION: Although it is rare, TOS could be due to superior mediastinal mass and the treatment of choice is total resection either through median sternotomy or thoracoscopic procedure.

Modified transmanubrial approach for complicated type 1 cervical rib resection requiring subclavian artery reconstruction.

The transmanubrial musculoskeletal sparing approach (TMA) is commonly used for resecting apical lung tumours with vascular involvement. Non-neoplastic conditions which might require surgical exploration of the thoracic outlet include the 'cervical rib', a clinical condition consisting of an additional rib forming above the first rib and growing from the base of the neck just above the clavicle. Type 1 cervical rib-when a complete cervical rib articulates with the first rib or manubrium of the sternum-is the most challenging scenario where the subclavian artery can be damaged by continuous compression due to the narrow space between clavicle, first rib and supernumerary cervical rib, requiring prosthetic reconstruction of the involved tract. Here, we describe a modified TMA in which the incision in the neck is conducted posteriorly to the sternocleidomastoid muscle, thus allowing safe dissection of the superior and middle trunk of the brachial plexus.

Double Trouble: Combined Neurogenic Thoracic Outlet Syndrome and Superior Labrum Anterior Posterior Tear.

Neurogenic thoracic outlet syndrome and superior labrum anterior posterior tears are usually treated in a staged manner due to different post-operative therapy needs. This case describes successful combined surgery with expedited physical therapy.

Thoracic Outlet Syndrome Caused by a Primary Tumour in the Brachial Plexus.

Thoracic outlet syndrome (TOS) caused by a primary brachial plexus tumour is very rare. A male politician in his 40s presented with numbness, left limb pain and positive Wright and Roos test results. Magnetic resonance imaging (MRI) revealed a tumour located just below the clavicle, compressing the subclavian artery during left arm elevation. Despite concerns regarding postoperative nerve deficits, surgery was performed because of worsening symptoms during the election campaigns. The pathology report revealed a schwannoma. Few reports have described TOS caused by primary tumours of the brachial plexus. While the decision to perform surgery for primary tumours of the brachial plexus requires careful consideration, surgery may be indicated in cases where the tumour location causes such symptoms. Level of Evidence: Level V (Therapeutic).

Thoracic outlet syndrome in females: A systematic review.

Thoracic outlet syndrome (TOS) is a rare anatomic condition caused by compression of neurovascular structures as they traverse the thoracic outlet. Depending on the primary structure affected by this spatial narrowing, patients present with one of three types of TOS-venous TOS, arterial TOS, or neurogenic TOS. Compression of the subclavian vein, subclavian artery, or brachial plexus leads to a constellation of symptoms, including venous thrombosis, with associated discomfort and swelling; upper extremity ischemia; and chronic pain due to brachial plexopathy. Standard textbooks have reported a predominance of females patients in the TOS population, with females comprising 70%. However, there have been few comparative studies of sex differences in presentation, treatment, and outcomes for the various types of TOS.

Robot-Assisted Retroauricular Anterior Scalenectomy for Neurogenic Thoracic Outlet Syndrome.

Background: This study described the surgical technique of a robot-assisted retroauricular anterior scalenectomy and assessed clinical outcomes and complications for patients with neurogenic thoracic outlet syndrome (nTOS). Methods: Between February 2014 and August 2016, 5 patients underwent robot-assisted retroauricular anterior scalenectomy using the da Vinci Xi system for nTOS. For clinical assessment, visual analog scale (VAS) symptom score, pinch and grip strength, and disabilities of arm, shoulder and hand (DASH) score were assessed to compare preoperative and postoperative outcomes. Postoperative complications were also reviewed. Results: The VAS symptom, pinch and grip strength, and DASH scores improved 1 year after the operation. All patients were satisfied with the surgical scars. Temporary postoperative complications, which spontaneously resolved within 3 months, were noticed in 2 patients: one with vocal cord palsy and the other with upper brachial plexus palsy. Conclusions: The robot-assisted retroauricular anterior scalenectomy for patients with nTOS seems feasible and safe, providing satisfactory cosmetic results.

Efficacy and Safety of Supraclavicular Thoracic Outlet Decompression.

OBJECTIVES: We aimed to report efficacy, safety, and health-related quality of life (HRQoL) outcomes of a multidisciplinary treatment approach including supraclavicular thoracic outlet decompression among patients with thoracic outlet syndrome (TOS). BACKGROUND: TOS is a challenging condition where controversy remains in diagnosis and treatment, primarily given a lack of data exploring various treatment approaches and associated patient outcomes. METHODS: Patients who underwent unilateral, supraclavicular thoracic outlet decompression, or pectoralis minor tenotomy for neurogenic, venous, or arterial TOS were identified from a prospectively maintained database. Demography, use of preoperative botulinum toxin injection, and participation in multidisciplinary evaluation were measured. The primary endpoints were composite postoperative morbidity and symptomatic improvement compared with baseline. RESULTS: Among 2869 patients evaluated (2007-2021), 1032 underwent surgery, including 864 (83.7%) supraclavicular decompressions and 168 (16.3%) isolated pectoralis minor tenotomies. Predominant TOS subtypes among surgical patients were neurogenic (75.4%) and venous TOS (23.4%). Most patients (92.9%) with nTOS underwent preoperative botulinum toxin injection; 56.3% reported symptomatic improvement. Before surgical consultation, few patients reported participation in physical therapy (10.9%). The median time from first evaluation to surgery was 136 days (interquartile range: 55, 258). Among 864 patients who underwent supraclavicular thoracic outlet decompression, complications occurred in 19.8%; the most common complication was chyle leak (8.3%). Four patients (0.4%) required revisional thoracic outlet decompression. At a median follow-up of 420 days (interquartile range: 150, 937) 93.3% reported symptomatic improvement. CONCLUSION: Based on low composite morbidity, need for very few revisional operations, and high rates of symptomatic improvement, a multidisciplinary treatment approach including primarily supraclavicular thoracic outlet decompression is safe and effective for patients with TOS.

Delay in Diagnosis for Two Patients With McCleery Syndrome.

McCleery syndrome is a rare form of venous thoracic outlet syndrome characterized by intermittent obstruction of the subclavian vein (SCV) without thrombosis. In 2022, two patients presented to our clinic with McCleery syndrome after living with venous symptoms for over one year. Duplex scans of both patients revealed compression of the SCV on abduction. A first rib resection and anterior scalenectomy were performed to decompress the SCV. At two weeks post-op, a follow-up venogram revealed widely patent, unobstructed SCVs in both patients.

The effects of major depression disorder on neurogenic thoracic outlet syndrome surgery outcomes.

OBJECTIVES: Thoracic outlet syndrome (TOS) is a group of disorders caused by impingement of the neurovascular structures at the thoracic outlet. Neurogenic TOS (nTOS), which is thought to be caused by a compression of the brachial plexus, accounts for more than 90% of the cases. Although treatment for nTOS is successful through physiotherapy and/or surgical decompression, little is known about the impact of psychosocial factors, namely, major depressive disorder (MDD), on postoperative outcomes such as non-routine discharge (NRD). Here, we assess whether MDD predicts the type of discharge following nTOS surgical intervention. METHODS: A retrospective analysis of the National Inpatient Sample database from the years 2005-2018 was performed. Using the International Classification of Diseases Clinical Modification, Ninth and Tenth revisions, patients who underwent a surgical intervention for nTOS were identified. Our primary outcome was to investigate the effects of MDD on nTOS patient disposition status after surgical management; secondary outcomes included analysis of total hospital charges and length of stay. NRD was defined as anything beyond discharge home without healthcare services. Univariate and multivariable logistic regression analyses were conducted to assess MDD and other potential independent predictors of NRD and prolonged hospital stay (> 2 days) following surgical intervention. RESULTS: A total of 6099 patients were identified: 596 (9.77%) patients with MDD and 5503 (90.23%) without MDD. On average, patients with MDD were older (39.6 ± 12.0 years vs. 36.0 ± 13.0 years; p < 0.001), female (80.7% vs. 63.5%; p < 0.001), white (89.6% vs. 85.6%; p = 0.030), and on Medicare (9.6% vs 5.2%; p < 0.001). Univariate and multivariable logistic regression models identified MDD as an independent risk factor associated with a higher risk of NRD (adjusted odds ratio [aOR], 1.50; 95% confidence interval [CI], 1.0-2.2). Additionally, chronic kidney disease (aOR, 2.60; 95% CI, 1.2-5.4), postoperative complications (aOR, 1.87; 95% CI, 1.2-2.9), and Medicare (aOR, 2.95; 95% CI, 1.9-4.7) were statistically significant predictors for higher risk of NRD. However, MDD was not associated with prolonged hospital stay (aOR, 1.00; 95% CI, 0.8-1.2) or higher median of total charges (MDD group: $27,867 vs. non-MDD group: $28,123; p = 0.799). CONCLUSION: Comorbid MDD was strongly associated with higher NRD rates following nTOS surgical intervention. MDD had no significant impact on length of hospital stay or total hospital charges. Additional prospective research is necessary in order to better evaluate the impact of MDD in patients with nTOS.

Thoracic outlet syndrome: a retrospective analysis of robotic assisted first rib resections.

Thoracic Outlet Syndrome (TOS) is caused by compression of the neurovascular bundle between the first rib and the clavicula, which can cause a large panel of symptoms and has a reported incidence of approximately 2-4/100.000. Surgical treatment consists of the resection of the first rib and is historically performed using an open, mainly transaxillary, approach. Recent developments resulted in a minimally invasive approach using Robotic Assisted Thoracic Surgery (RATS). With this study, the investigators want to provide a descriptive study of first rib resection using RATS approach at two different centers. We reviewed the files of 47 patients affected by TOS and who benefited from first rib resection using RATS approach between 2016 and 2021. Patient characteristics as well as Length of Stay (LOS), affected side, operative time (OT), complications, etiology, VAS score and post-operative QOL were gathered in the database. Statistical analysis was performed using IBM SPSS statistics 25 ®. Results were reported in mean and standard deviation. 47 patients affected by TOS received first rib resection using robotic approach. Mean age was 47 ± 12 yrs. 16 patients were operated on the left side and 31 on the right side. All the patients reported complete resolution of symptoms. At 1-year follow-up, no patient suffered from recurrence. There were no intraoperative complications. Postoperative complications occurred in two patients, one patient developed pneumothorax after chest tube removal and one patient developed recurrent pleural effusion which required surgery. Mean LOS was 3 ± 1 days and mean OT was 122 ± 40 min. First rib resection performed using a RATS approach is a safe technique with excellent outcomes and which is beneficial for the patient in terms of LOS, pain and symptom resolution.

Arterial thoracic outlet syndrome: a 30-year experience in a high-volume referral center.

BACKGROUND: The purpose of this study was to assess the clinical presentation and contemporary management of arterial thoracic outlet syndrome (TOS) in high-volume referral center. METHODS: We conducted a retrospective review of a prospectively maintained database of patients with TOS of any etiology between January 1st 1990 and 2021. Supra-, or combined supra-/infraclavicular approaches have been used for decompression/vascular reconstructions. The group was divided into two equal time periods: period 1 (1990-2006, N.=27) and period 2 (2006-2021, N.=36). RESULTS: Sixty-three consecutive patients underwent surgical treatment due to arterial TOS. Period 2 had more patients who were asymptomatic (N.=16, 44.4% vs. N.=0, 0%, P<0.001) and those presenting with critical hand ischemia (N.=12, 33.3% vs. N.=0, 0%, P=0.01), while acute limb ischemia was more common in period 1 (N.=16, 59.2% vs. N.=5, 13.9%, P<0.001). SA compression without lesion was more common in period 2 (N.=16, 44.4% vs. N.=0, 0%, P<0.001), while SA intimal damage with mural thrombus formation was more common in the period 1 (N.=12, 44.4% vs. N.=1, 2.7%, P<0.001). Decompression as an isolated procedure was performed in 25.4% (N.=16) of all asymptomatic patients, while combined decompressive and vascular procedure in 71.4% (N.=45) of patients. The most common postoperative complication was pneumothorax (N.=7, 11.1%). CONCLUSIONS: The supraclavicular approach with its modifications provides adequate decompression and allows also repair or reconstruction of the SA, as well as complete additional revascularization of the upper extremity without the need for further patient repositioning. While treatment methods and early outcomes have not changed significantly over time, there has been a trend towards different clinical and SA pathomorphological presentation.

Thoracic outlet syndrome: a review.

Thoracic outlet syndrome (TOS) is a rare condition (1-3 per 100,000) caused by neurovascular compression at the thoracic outlet and presents with arm pain and swelling, arm fatigue, paresthesias, weakness, and discoloration of the hand. TOS can be classified as neurogenic, arterial, or venous based on the compressed structure(s). Patients develop TOS secondary to congenital abnormalities such as cervical ribs or fibrous bands originating from a cervical rib leading to an objectively verifiable form of TOS. However, the diagnosis of TOS is often made in the presence of symptoms with physical examination findings (disputed TOS). TOS is not a diagnosis of exclusion, and there should be evidence for a physical anomaly that can be corrected. In patients with an identifiable narrowing of the thoracic outlet and/or symptoms with a high probability of thoracic outlet neurovascular compression, diagnosis of TOS can be established through history, a physical examination maneuvers, and imaging. Neck trauma or repeated work stress can cause scalene muscle scaring or dislodging of a congenital cervical rib that can compress the brachial plexus. Nonsurgical treatment includes anti-inflammatory medication, weight loss, physical therapy/strengthening exercises, and botulinum toxin injections. The most common surgical treatments include brachial plexus decompression, neurolysis, and scalenotomy with or without first rib resection. Patients undergoing surgical treatment for TOS should be seen postoperatively to begin passive/assisted mobilization of the shoulder. By 8 weeks postoperatively, patients can begin resistance strength training. Surgical treatment complications include injury to the subclavian vessels potentially leading to exsanguination and death, brachial plexus injury, hemothorax, and pneumothorax. In this review, we outline the diagnostic tests and treatment options for TOS to better guide clinicians in recognizing and treating vascular TOS and objectively verifiable forms of neurogenic TOS.

Thoracic outlet syndrome: a review for the primary care provider.

CONTEXT: Thoracic outlet syndrome (TOS) symptoms are prevalent and often confused with other diagnoses. A PubMed search was undertaken to present a comprehensive article addressing the presentation and treatment for TOS. OBJECTIVES: This article summarizes what is currently published about TOS, its etiologies, common objective findings, and nonsurgical treatment options. METHODS: The PubMed database was conducted for the range of May 2020 to September 2021 utilizing TOS-related Medical Subject Headings (MeSH) terms. A Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) systematic literature review was conducted to identify the most common etiologies, the most objective findings, and the most effective nonsurgical treatment options for TOS. RESULTS: The search identified 1,188 articles. The automated merge feature removed duplicate articles. The remaining 1,078 citations were manually reviewed, with articles published prior to 2010 removed (n=771). Of the remaining 307 articles, duplicate citations not removed by automated means were removed manually (n=3). The other exclusion criteria included: non-English language (n=21); no abstracts available (n=56); and case reports of TOS occurring from complications of fractures, medical or surgical procedures, novel surgical approaches, or abnormal anatomy (n=42). Articles over 5 years old pertaining to therapeutic intervention (mostly surgical) were removed (n=18). Articles pertaining specifically to osteopathic manipulative treatment (OMT) were sparse and all were utilized (n=6). A total of 167 articles remained. The authors added a total of 20 articles that fell outside of the search criteria, as they considered them to be historic in nature with regards to TOS (n=8), were related specifically to OMT (n=4), or were considered sentinel articles relating to specific therapeutic interventions (n=8). A total of 187 articles were utilized in the final preparation of this manuscript. A final search was conducted prior to submission for publication to check for updated articles. Symptoms of hemicranial and/or upper-extremity pain and paresthesias should lead a physician to evaluate for musculoskeletal etiologies that may be contributing to the compression of the brachial plexus. The best initial provocative test to screen for TOS is the upper limb tension test (ULTT) because a negative test suggests against brachial plexus compression. A positive ULTT should be followed up with an elevated arm stress test (EAST) to further support the diagnosis. If TOS is suspected, additional diagnostic testing such as ultrasound, electromyography (EMG), or magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) might be utilized to further distinguish the vascular or neurological etiologies of the symptoms. Initial treatment for neurogenic TOS (nTOS) is often conservative. Data are limited, therefore there is no conclusive evidence that any one treatment method or combination is more effective. Surgery in nTOS is considered for refractory cases only. Anticoagulation and surgical decompression remain the treatment of choice for vascular versions of TOS. CONCLUSIONS: The most common form of TOS is neurogenic. The most common symptoms are pain and paresthesias of the head, neck, and upper extremities. Diagnosis of nTOS is clinical, and the best screening test is the ULTT. There is no conclusive evidence that any one treatment method is more effective for nTOS, given limitations in the published data. Surgical decompression remains the treatment of choice for vascular forms of TOS.

A Rare Case of Bilateral Neurogenic Thoracic Outlet Syndrome Following Neck Injury.

Thoracic Outlet Syndrome (TOS) is a rare condition caused by compression of the neurovascular structures of the thoracic outlet. Patients with TOS are found to have a greater prevalence of supernumerary or abnormal first ribs compared to the general population. Symptoms can sometimes be incited by a neck injury, especially in patients with abnormal cervical anatomy. This case report highlights a unique patient with bilateral cervical ribs who presented with complicated symptoms following a neck injury who required a series of surgical interventions to improve.

Reliability and validity of the standardized elevated arm stress test in the diagnosis of neurogenic thoracic outlet syndrome.

OBJECTIVE: We developed a standardized elevated arm stress test (sEAST) meter to standardize patients' posture and measure additional grip and fatigue parameters. In the present prospective cohort study, we aimed to determine the reliability and validity of the sEAST in the diagnosis of neurogenic thoracic outlet syndrome (NTOS). METHODS: Patients evaluated for NTOS between October 2018 and February 2020 were included and performed the sEAST. The patients were classified into a proven NTOS group or a symptomatic control group using the reporting standards for NTOS and the outcome of thoracic outlet decompression surgery. Healthy persons were recruited as an asymptomatic control group. The test-retest reliability, area under the receiver operating characteristic curve, and positive and negative predictive values were calculated for each sEAST parameter. RESULTS: A total of 426 patients with suspected NTOS and 147 healthy controls had performed the sEAST. The validity analysis was performed with data from 111 patients with proven NTOS, 94 symptomatic controls, and 147 asymptomatic controls. The reporting standards were inconclusive for 116 patients; 77 patients had been excluded because thoracic outlet decompression surgery had not been performed or was unsuccessful, and 28 because they had arterial or venous thoracic outlet syndrome. The area under the receiver operating characteristic curve for the proven NTOS group compared with the asymptomatic control and symptomatic control groups ranged from 0.59 to 0.77 and 0.54 to 0.63, respectively. The positive predictive value ranged from 46% to 65% and the negative predictive value from 51% to 66%. The test-retest reliability analysis for 80 patients with multiple sEAST measurements showed moderate to good (0.52-0.87) intraclass correlation coefficient values for the duration and grip strength parameters. However, the grip fatigue parameters demonstrated poor (0.46-0.16) intraclass correlation coefficient values. CONCLUSIONS: The sEAST showed good test-retest reliability for the duration and grip strength parameters. However, the discriminative value of all sEAST parameters was low for NTOS diagnostics. The good test-retest reliability of the sEAST parameters indicates that they could be valuable outcome measures for comparison in a diagnostic care pathway.

Thoracic Outlet Syndrome Part I: Systematic Review of the Literature and Consensus on Anatomy, Diagnosis, and Classification of Thoracic Outlet Syndrome by the European Association of Neurosurgical Societies' Section of Peripheral Nerve Surgery.

BACKGROUND: Although numerous articles have been published not only on the classification of thoracic outlet syndrome (TOS) but also on diagnostic standards, timing, and type of surgical intervention, there still remains some controversy because of the lack of level 1 evidence. So far, attempts to generate uniform reporting standards have not yielded conclusive results. OBJECTIVE: To systematically review the body of evidence and reach a consensus among neurosurgeons experienced in TOS regarding anatomy, diagnosis, and classification. METHODS: A systematic literature search on PubMed/MEDLINE was performed on February 13, 2021, yielding 2853 results. Abstracts were screened and classified. Recommendations were developed in a meeting held online on February 10, 2021, and refined according to the Delphi consensus method. RESULTS: Six randomized controlled trials (on surgical, conservative, and injection therapies), 4 "guideline" articles (on imaging and reporting standards), 5 observational studies (on diagnostics, hierarchic designs of physiotherapy vs surgery, and quality of life outcomes), and 6 meta-analyses were identified. The European Association of Neurosurgical Societies' section of peripheral nerve surgery established 18 statements regarding anatomy, diagnosis, and classification of TOS with agreement levels of 98.4 % (±3.0). CONCLUSION: Because of the lack of level 1 evidence, consensus statements on anatomy, diagnosis, and classification of TOS from experts of the section of peripheral nerve surgery of the European Association of Neurosurgical Societies were developed with the Delphi method. Further work on reporting standards, prospective data collections, therapy, and long-term outcome is necessary.