Helical computed tomography of the normal thoracic outlet

Crossed raised arm position improves the flow of contrast medium in torso contrast-enhanced computed Tomography

INTRODUCTION

This retrospective cohort study examined the effects of the crossed raised arm (CRA) position in contrast-enhanced computed tomography (CECT) on contrast medium influx and image quality relative to the conventional position.

METHODS

Contrast medium influx into the collateral veins on CECT images was evaluated in 92 participants. The CT values of the pulmonary artery, descending aorta, and spleen were obtained in both positions and compared. Anatomical changes in the diameters and area of the subclavian vein and costoclavicular distance were also analyzed.

RESULTS

Contras 27 and 6 patients in the conventional and CRA positions, respectively. The influx risk ratio in the CRA position versus that in the conventional position was 0.22 (95% confidence interval, 0.10-0.51). Elevations in the median CT value of the pulmonary artery, descending aorta, and spleen in the CRA position were 7.0% (p < .001), 7.4% (p < .001), and 9.8% (p < .001), respectively. Enlargements in the major and minor diameters of the subclavian vein, subclavian vein area, and costoclavicular distance in the CRA position versus those in the conventional position were 19.3% (p < .001), 28.1% (p < .001), 53.6%, and 30.0% (p < .001), respectively.

CONCLUSION

The CRA position effectively prevented contrast medium influx into the collateral veins due to SVS and increased CT values in the target organs in CECT. The diameters and area of the subclavian vein and costoclavicular distance were enlarged at the thoracic outlet, which improved the flow of the contrast medium into the targeted organs.

IMPLICATIONS FOR PRACTICE

The CRA position can contribute to obtaining better CECT images during common clinical assessments at no additional cost.

Diagnostic and Therapeutic Management of the Thoracic Outlet Syndrome. Review of the Literature and Report of an Italian Experience

The Thoracic Outlet Syndrome is a clinical potentially disabling condition characterized by a group of upper extremity signs and symptoms due to the compression of the neurovascular bundle passing through the thoracic outlet region. Because of the non-specific nature of signs and symptoms, to the lack of a consensus for the objective diagnosis, and to the wide range of etiologies, the actual figure is still a matter of debate among experts. We aimed to summarize the current evidence about the pathophysiology, the diagnosis and the treatment of the thoracic outlet syndrome, and to report a retrospective analysis on 324 patients followed for 5 years at the Padua University Hospital and at the Naples Fatebenefratelli Hospital in Italy, to verify the effectiveness of a specific rehabilitation program for the syndrome and to evaluate if physical therapy could relieve symptoms in these patients.

A Review of Upper Extremity Peripheral Nerve Injuries in Throwing Athletes

Peripheral nerve injuries in the upper extremities may be common in throwing athletes as the throwing motion places extreme stress on the dominant arm. The combination of extreme stress along with repetitive microtrauma from throwing uniquely places the throwing athlete at elevated risk of upper extremity peripheral nerve injury. However, because symptoms can be non-specific and frequent co-exist with pathology in the upper extremity, the diagnosis of peripheral nerve injury is often delayed. Diagnosis of peripheral nerve injuries may require a combination of history and physical exam, diagnostic imaging, electrodiagnostic testing, and diagnostic ultrasound guided injections. The primary management should include physical therapy focusing on throwing mechanics and kinetic chain evaluation. However, some athletes require surgical intervention if symptoms do not improve with conservative management. The purpose of this focused narrative review is to highlight upper extremity peripheral neuropathies reported in throwing athletes and to provide an overview of the appropriate clinical diagnosis and management of the throwing athlete with a peripheral nerve injury. This article is protected by copyright. All rights reserved.

Thoracic Outlet Syndrome: Fingertip Cannot Replace Forearm Photoplethysmography in the Evaluation of Positional Venous Outflow Impairments

Objective: Fingertip photoplethysmography (PPG) resulting from high-pass filtered raw PPG signal is often used to record arterial pulse changes in patients with suspected thoracic outlet syndrome (TOS). Results from venous (low-pass filtered raw signal) forearm PPG (V-PPG) during the Candlestick-Prayer (Ca + Pra) maneuver were recently classified into four different patterns in patients with suspected TOS, two of which are suggestive of the presence of outflow impairment. We aimed to test the effect of probe position (fingertip vs. forearm) and of red (R) vs. infrared (IR) light wavelength on V-PPG classification and compared pattern classifications with the results of ultrasound (US).

Methods: In patients with suspected TOS, we routinely performed US imaging (US + being the presence of a positional compression) and Ca + Pra tests with forearm V-PPG_IR. We recruited patients for a Ca + Pra maneuver with the simultaneous fingertip and forearm V-PPG_R. The correlation of each V-PPG recording to each of the published pattern profiles was calculated. Each record was classified according to the patterns for which the coefficient of correlation was the highest. Cohen’s kappa test was used to determine the reliability of classification among forearm V-PPG_IR, fingertip V-PPG_R, and forearm V-PPG_R.

Results: We obtained 40 measurements from 20 patients (40.2 ± 11.3 years old, 11 males). We found 13 limbs with US + results, while V-PPG suggested the presence of venous outflow impairment in 27 and 20 limbs with forearm V-PPG_IR and forearm V-PPG_R, respectively. Fingertip V-PPG_R provided no patterns suggesting outflow impairment.

Conclusion: We found more V-PPG patterns suggesting venous outflow impairment than US + results. Probe position is essential if aiming to perform upper-limb V-PPG during the Ca + Pra maneuver in patients with suspected TOS. V-PPG during the Ca + Pra maneuver is of low cost and easy and provides reliable, recordable, and objective evidence of forearm swelling. It should be performed on the forearm (close to the elbow) with either PPG_R or PPG_IR but not at the fingertip level.

Venous thoracic outlet syndrome

Venous thoracic outlet syndrome (vTOS) is a spectrum of disease caused by external compression of the subclavian vein as it passes through the costoclavicular space. Paget-Schroetter's Syndrome (PSS) or effort thrombosis is a subtype of vTOS where compression and microtrauma to subclavian vein from repetitive arm movements results in venous thrombosis. PSS or effort thrombosis mostly affects young otherwise healthy active individuals, and this further highlights the importance of this condition. Early diagnosis and aggressive early intervention aimed at complete resolution of acute symptoms and minimizing the risk of recurrence is ultimately important and increases the likelihood of the full restoration of limb function. Several noninvasive imaging techniques are currently available to confirm the initial diagnosis including Doppler ultrasound, contrast-enhanced computed tomography, and magnetic resonance imaging. Following diagnosis, multiple algorithms exist for the management of PSS and almost all require a multidisciplinary approach. Like any other condition involving the thrombosis of deep venous system, initial step in the management is anticoagulation. Catheter-directed therapies (CDT) have also a pivotal role as the initial treatment to resolve the acute thrombosis and establish venous patency. CDT combined with medical anticoagulation and surgical decompression are the components of most treatment algorithms for the management of patients suffering from PSS.

Upper Extremity Deep Vein Thrombosis: Current Knowledge and Future Directions

Upper extremity deep vein thrombosis (UEDVT) has been increasing in incidence due to the escalating use of central venous catheters such as peripherally inserted central catheters. UEDVT can be primary idiopathic or secondary to pacemaker leads, intravascular catheters or cancer. In comparison to conventional venous thromboembolism such as lower limb deep vein thrombosis or pulmonary embolism the risk factors, investigations, and management are not well defined. We review current evidence in primary and secondary UEDVT, highlighting areas in need of further research. We also explore the entity of venous thoracic outlet syndrome, which is said to be a risk factor for recurrent primary UEDVT and is the rationale behind surgical interventions.

Evaluation and Management of Arterial Thoracic Outlet Syndrome

Arterial thoracic outlet syndrome is rare and may be associated with a bony anomaly. Patient presentation can range from mild arm discoloration and claudication to severe limb-threatening ischemia. For patients with subclavian artery dilation without secondary complications, thoracic outlet decompression and arterial surveillance is sufficient. Patients with subclavian artery aneurysms or distal embolization require decompression with reconstruction or thromboembolectomy and distal bypass respectively.

Normal Costoclavicular Distance as a Standard in the Radiological Evaluation of Thoracic Outlet Syndrome in the Costoclavicular Space

BACKGROUND

The costoclavicular space is a common site of thoracic outlet syndrome. When there is no anatomical alteration, the diagnosis of thoracic outlet syndrome is difficult. Several authors relate costoclavicular distance to symptoms of thoracic outlet syndrome; however, there is no standardized site for measurement of the costoclavicular distance. This study aimed to determine the standard costoclavicular distance at neurovascular bundle crossing points (near the subclavian vein [Measure V] and the subclavian artery/brachial plexus branches [Measure NA]) using high-resolution chest computed tomography (CT) scans and evaluate its variations with respect to age, sex, height, and body mass index.

METHODS

This prospective cross-sectional observational study analyzed 150 of 156 CT scans from consecutive adult patients (72 females and 78 males). Costoclavicular distance was measured at the subclavian vein and brachial plexus/subclavian artery sites, where narrowing of the costoclavicular distance could lead to symptoms of thoracic outlet syndrome. Costoclavicular distance was analyzed with respect to sex, laterality, age group (<50 and ≥50 years) and body mass index group (body mass index <25 and ≥25 kg/m²).

RESULTS

Measures of V and NA were normally distributed. The measured costoclavicular distances were 1.23 cm (±0.40) and 1.24 cm (±0.47), respectively. Age (≥50 years) and body mass index (≥25 kg/m²) increased the costoclavicular distance. Measurements V and NA below the fifth percentile indicated a narrowed costoclavicular distance and a greater chance of developing thoracic outlet syndrome. For young (<50 years) and eutrophic patients (body mass index <25 kg/m²), these measurements were 0.46 and 0.44 cm, respectively; for young people and body mass index ≥25 kg/m², they were 0.54 and 0.24 cm, respectively; for the elderly (≥50 years) and eutrophic, they were 0.57 and 0.48 cm, respectively; and for the elderly and body mass index ≥ 25 kg/m², they were 0.83 and 0.73 cm, respectively. There was no significant difference between measurements V and NA regarding patient laterality, gender, and height.

CONCLUSIONS

Standardization of costoclavicular distance measurements at neurovascular bundle crossing points (subclavian vein and brachial plexus/subclavian artery) is possible. It may aid the diagnosis and help direct the therapeutic indications for symptomatic patients with thoracic outlet syndrome.

Classification of stress fractures of the first rib in adolescent athletes

Stress fractures of the first rib occur infrequently in adolescent athletes; therefore, there have been few case reports. Initial radiographs do not always lead to the diagnosis of first rib stress fractures. This study proposed a classification system and a possible mechanism for stress fractures of the first rib using three-dimensional computed tomography (3D-CT). The data of 10 stress fractures of the first rib in adolescent athletes obtained using 3D-CT between 2007 and 2018 were reviewed. Fractures of the first rib were classified according to the location and type of the fracture line. Stress fractures of the first rib were classified into three types: type 1, center-transverse fracture; type 2, center to posterior-oblique fracture; and type 3, posterior-transverse fracture. There were three type 1 fractures, five type 2 fractures, and two type 3 fractures. The fracture lines of types 1 and 2 were on the deep groove of the subclavian artery between the anterior and middle scalene muscle attachments, which is the thinnest and weakest portion of the first rib. However, the fracture line of type 3 was across the posterior part of the first rib and located slightly away from the deep groove of the subclavian artery. A 3D-CT classification of stress fractures of the first rib in adolescent athletes was proposed. Our results suggested that there are three types of the fracture and different mechanisms that cause this type of injury. This classification system helped to implement adequate conservative therapeutic plans based on the proposed mechanism.

Clinical, electrodiagnostic and imaging features of true neurogenic thoracic outlet syndrome: Experience at a tertiary referral center

OBJECTIVE

True neurogenic thoracic outlet syndrome (TN-TOS) is an extremely rare neuromuscular disease. We report clinical, electrodiagnostic and radiologic features of patients with TN-TOS.

METHODS

Retrospective chart review of patients satisfying criteria was done. Nerve conduction study (NCS) and needle electromyography (EMG) of upper extremity were reviewed. Brachial plexus MRI and computed tomography angiography (CTA) were also reviewed.

RESULTS

Thirteen TN-TOS patients were identified. The most common neurologic signs were hypesthesia in the medial forearm or ulnar digits and weakness of the abductor pollicis brevis (APB) muscle. In NCS, medial antebrachial cutaneous (MABC) sensory nerve action potential amplitude was decreased in all tested patients. The APB muscle was most commonly involved in EMG. Among radiologic criteria, focal stenosis of subclavian artery in CTA was the most common finding.

CONCLUSION

We confirmed that TN-TOS is T1 predominant lower roots/trunk brachial plexopathy with clinical and electrodiagnostic features. Radiologic studies may be used to detect structural abnormalities.

SIGNIFICANCE

As MABC NCS showed abnormal results in all tested patients, it should be added to electrodiagnostic study as screening method. If present, structural abnormalities might be confirmed with radiologic studies.

Diagnosing Thoracic Outlet Syndrome: Current Approaches and Future Directions

The diagnosis of thoracic outlet syndrome (TOS) has long been a controversial and challenging one. Despite common presentations with pain in the neck and upper extremity, there are a host of presenting patterns that can vary within and between the subdivisions of neurogenic, venous, and arterial TOS. Furthermore, there is a plethora of differential diagnoses, from peripheral compressive neuropathies, to intrinsic shoulder pathologies, to pathologies at the cervical spine. Depending on the subdivision of TOS suspected, diagnostic investigations are currently of varying importance, necessitating high dependence on good history taking and clinical examination. Investigations may add weight to a diagnosis suspected on clinical grounds and suggest an optimal management strategy, but in this changing field new developments may alter the role that diagnostic investigations play. In this article, we set out to summarise the diagnostic approach in cases of suspected TOS, including the importance of history taking, clinical examination, and the role of investigations at present, and highlight the developments in this field with respect to all subtypes. In the future, we hope that novel diagnostics may be able to stratify patients according to the exact compressive mechanism and thereby suggest more specific treatments and interventions.

Dynamic CT angiography for the diagnosis of patients with thoracic outlet syndrome: Correlation with patient symptoms

INTRODUCTION

Vasculo-nervous structures serving the upper limbs may be compressed as they pass through three areas: the inter-scalene triangle (IST), the costo-clavicular space (CCS) and the retropectoralis minor space (RMS). The diagnosis of thoracic outlet syndrome (TOS) is essentially clinical, but requires imaging to specify the site of compression, its grade and the existence of predisposing anatomical factors, in order to guide the treatment and eliminate the main differential diagnoses.

MATERIAL AND METHODS

Images from 141 patients who underwent dynamic CT angiography of the thoracic outlets from June 2008 to January 2015 were analyzed retrospectively. Patients had unilateral or bilateral vascular, neurological, mixed or atypical symptoms. We studied the degree of stenosis of the subclavian artery with the following grading system: 1 (0-<25%), 2 (25-<50%), 3 (50-<75%), 4 (75-100%). The site of stenosis and the presence of underlying anatomical predisposing factors were also taken in account.

RESULTS

A total of 221 thoracic outlets were analyzed. Symptoms were neurological, mixed, vascular and atypical in 30%, 28%, 13% and 12%, respectively. Among patients with bilateral acquisitions, 38 outlets were asymptomatic; 40% of symptomatic outlets and only 5% of asymptomatic ones had grade 3 or 4 stenosis. 63% of the stenosis were in the CCS and 37% in the IST; 21% had a predisposing anatomical factor most often a costo-clavicular anomaly, associated with significant stenosis in 50% of cases.

CONCLUSION

Vascular stenosis of more than 50% on dynamic CT angiography is strongly associated with TOS. Predisposing factors were present in 21% of cases, causing significant vascular stenosis in half, underscoring the need for functional evaluation.

Cervical Rib Prevalence and its Association with Thoracic Outlet Syndrome: A Meta-Analysis of 141 Studies with Surgical Considerations

BACKGROUND

Cervical ribs (CR) are supernumerary ribs that arise from the seventh cervical vertebra. In the presence of CR, the boundaries of the interscalene triangle can be further constricted and result in neurovascular compression and thoracic outlet syndrome (TOS). The aim of our study was to provide a comprehensive evidence-based assessment of CR prevalence and their association with TOS as well as surgical approach to excision of CR and surgical patients' characteristics.

METHODS

A thorough search of major electronic databases was conducted to identify any relevant studies. Data on the prevalence, laterality, and side of CR were extracted from the eligible studies for both healthy individuals and patients with TOS. Data on the type of TOS and surgical approach to excision of CR were extracted as well.

RESULTS

A total of 141 studies (n = 77,924 participants) were included into the meta-analysis. CR was significantly more prevalent in patients with TOS than in healthy individuals, with pooled prevalence estimates of 29.5% and 1.1%, respectively. More than half of the patients had unilateral CR in both the healthy and the TOS group. The analysis showed that 51.3% of the symptomatic patients with CR had vascular TOS, and 48.7% had neurogenic TOS. Most CR were surgically excised in women using a supraclavicular approach.

CONCLUSIONS

CR ribs are frequent findings in patients with TOS. We recommended counseling asymptomatic patients with incidentally discovered CR on the symptoms of TOS, so that if symptoms develop, the patients can undergo prompt and appropriate workup and treatment.

Choosing Surgery for Neurogenic TOS: The Roles of Physical Exam, Physical Therapy, and Imaging

Neurogenic thoracic outlet syndrome (nTOS) is characterized by arm and hand pain, paresthesias, and sometimes weakness resulting from compression of the brachial plexus within the thoracic outlet. While it is the most common subtype of TOS, nTOS can be difficult to diagnose. Furthermore, patient selection for surgical treatment can be challenging as symptoms may be vague and ambiguous, and diagnostic studies may be equivocal. Herein, we describe some approaches to aid in identifying patients who would be expected to benefit from surgical intervention for nTOS. We describe the role of physical examination, physical therapy, and imaging in the evaluation and diagnosis of nTOS.

Venous Compression Syndromes: a Review

OPINION STATEMENT

Venous compression syndromes present a diagnostic and therapeutic challenge as the clinical presentation can be vague, diagnostic criteria are often not present, and high quality standardization of when and how to treat is not available in part due to the limited number of cases reported and also due to the limited literature available. Significant venous compression should be considered when clinical symptoms correlate to location of compression and there is evidence of hemodynamic changes including venous hypertension, collateral/variceal formation, and/or thrombus formation. In general, treatment of venous compression should address the etiology of the compression as opposed to just treating symptoms associated with it such as significant varices or anticoagulation for thrombus to avoid recurrence of symptoms.

Computed Tomography Angiography to Evaluate Thoracic Outlet Neurovascular Compression

The objective was to evaluate the efficacy of computed tomography angiography with upper extremity hyperabduction to diagnose thoracic outlet syndrome. Over 5 years, 21 patients were treated surgically for neurogenic symptoms of thoracic outlet syndrome. For patients whose diagnosis was unclear after history and physical examination, adjunctive tests (duplex, magnetic resonance angiography, or computed tomography angiography) were performed to help establish the diagnosis. Five of the 6 computed tomography angiograms were positive. The sixth computed tomography was deemed to be an incomplete study. With mean follow-up of 9.4 months, 95% (n = 19) of patients with a positive hyperabduction test on physical examination were free of symptoms postoperatively. All patients with a positive computed tomography angiogram, with their neurovascular compression localized to the thoracic outlet, had successful operative decompression. Computed tomography angiogram with abduction of the arm can be used as an adjunct to confirm the diagnosis of neurovascular compression and then predict successful operative decompression.

Imaging of the Patient with Thoracic Outlet Syndrome

Patients with symptoms from compression of the neurovascular bundle in the thoracic outlet are described as having thoracic outlet syndrome (TOS), which is best thought of as three conditions classified according to which structures are involved. The purpose of this article is to review the role of imaging in evaluation of patients with TOS, beginning with diagnosis and extending through postoperative management. While diagnosis of TOS still rests on the patient's presenting history and physical examination, imaging examinations are helpful in supporting the diagnosis, delineating abnormal anatomy, determining which structures are compressed, identifying the site of compression, and excluding other diagnoses. Magnetic resonance imaging is the noninvasive imaging modality of choice in evaluating patients with suspected TOS, but computed tomography also plays an important role, particularly in delineating bone anatomy. Evidence of vascular damage is required to make the diagnosis of TOS at imaging. Dynamic compression of the axillosubclavian vessels at the thoracic outlet can be a finding supportive of the diagnosis of TOS but is not a stand-alone diagnostic criterion, as it can be seen in patients without TOS. As diagnosis and treatment of TOS increase, radiologists will increasingly encounter the TOS patient after decompression surgery. Recognition of the expected postoperative appearance of these patients is critical, as is an understanding of the imaging findings of potential short- and long-term complications. (©)RSNA, 2016.

State-of-the-art Magnetic Resonance Imaging in Vascular Thoracic Outlet Syndrome

Vascular thoracic outlet syndrome is caused by compression of subclavian/axillary vessels during their passage from the thoracic cavity to the axilla. Early diagnosis and treatment is important to prevent debilitating outcomes of vascular thoracic outlet syndrome. Contrast-enhanced three-dimensional (3D) magnetic resonance angiography (MRA) with equilibrium phase using provocative arm positioning is the optimal examination to determine presence, degree of vascular compression, and complications of vascular thoracic outlet syndrome. This article reviews thoracic outlet anatomy, disorders of the vascular component, and typical imaging findings by contrast-enhanced 3D MRA.

Thoracic outlet syndrome secondary to a mid-clavicle malunion

A 22-year-old man presented with a painful 'clunking' sensation in the right mid-clavicle, and pain and dysaesthesia along the medial aspect of his right arm and hand. Three months earlier, he had been involved in a vehicle accident and sustained a right clavicle fracture. He had a large step off of the right clavicle with a medialisation of the right shoulder. At 90° abduction in external rotation of both shoulders he developed pain, paraesthesia and disappearance of the right radial artery pulsation. CT of the right shoulder in the neutral position demonstrated the clavicle-to-first rib distance of 5.5 mm, MRI showed the clavicular bone callus had a mass effect with effacement of anterior fat adjacent to the brachial plexus cords. He was diagnosed with thoracic outlet syndrome and underwent a corrective right clavicle osteotomy with the use of an AcuMed superior clavicle plate.

Case report: Thoracic outlet syndrome in an elite archer in full-draw position

BACKGROUND

One possible pathomechanism of thoracic outlet syndrome (TOS) is shoulder abduction and extension inducing backward motion of the clavicle which causes compression on the brachial plexus. This position occurs during the full-draw stage of archery, by drawing and holding the bowstring.

CASE DESCRIPTION

A 28-year-old elite archer presented with a feeling of weakness and dull shoulder pain, and experienced decreased grip power and hypoesthesia in the ulnar nerve dermatome in the full-draw position. On CT angiography, the cross-sectional area of the subclavian artery in the costoclavicular space decreased to 40% compared with that of the subclavian artery in a noncompressed state. This patient had first rib resection through the supraclavicular approach with a clavicle osteotomy. At 3.5 years postoperatively, the patient maintained his job as a professional coach and did not have any specific complaints when teaching and demonstrating archery skills.

LITERATURE REVIEW

A literature review revealed numerous causes of TOS, ranging from congenital abnormalities to repetitive postures related to sports activities. The abduction and external rotation (ABER) position (shoulder at 90° abduction and external rotation) has been suggested for detecting TOS and is a documented cause of compression of the brachial plexus and subclavian vessels. We present the case of an archer with TOS association with repeated use of the ABER position.

PURPOSE AND CLINICAL RELEVANCE

TOS should be suspected when athletes repeatedly use shoulder extension and abduction for their sports if other pathologic conditions can be ruled out.

Thoracic outlet syndrome: a neurological and vascular disorder

Thoracic outlet syndrome (TOS) is a condition arising from compression of the subclavian vessels and/or brachial plexus as the structures travel from the thoracic outlet to the axilla. Despite the significant pathology associated with TOS, there remains some general disagreement among experts on the specific anatomy, etiology, and pathophysiology of the condition, presumably because of the wide variation in symptoms that manifest in presenting patients, and because of lack of a definitive gold standard for diagnosis. Symptoms associated with TOS have traditionally been divided into vascular and neurogenic categories, a distinction based on the underlying structure(s) implicated. Of the two, neurogenic TOS (nTOS) is more common, and typically presents as compression of the brachial plexus; primarily, but not exclusively, involving its lower trunk. Vascular TOS (vTOS) usually involves compression of the vessel, most commonly the subclavian artery or vein, or is secondary to thrombus formation in the venous vasculature. Any anatomical anomaly in the thoracic outlet has the potential to predispose a patient to TOS. Common anomalies include variations in the insertion of the anterior scalene muscle (ASM) or scalenus minimus muscle, the presence of a cervical rib or of fibrous and muscular bands, variations in insertion of pectoralis minor, and the presence of neurovascular structures, which follow an atypical course. A common diagnostic technique for vTOS is duplex imaging, which has generally replaced more invasive angiographic techniques. In cases of suspected nTOS, electrophysiological nerve studies and ASM blocks provide guidance when screening for patients likely to benefit from surgical decompression of TOS. Surgeons generally agree that the transaxillary approach allows the greatest field of view for first rib excision to relieve compressed vessels. Alternatively, a supraclavicular approach is favored for scalenotomies when the ASM impinges on surrounding structures. A combined supraclavicular and infraclavicular approach is preferred when a larger field of view is required. The future of TOS management must emphasize the improvement of available diagnostic and treatment techniques, and the development of a consensus gold standard for diagnosis. Helical computed tomography offers a three-dimensional view of the thoracic outlet, and may be valuable in the detection of anatomical variations, which may predispose patients to TOS. This review summarizes the history of TOS, the pertinent clinical and anatomical presentations of TOS, and the commonly used diagnostic and treatment techniques for the condition.

MRI findings in thoracic outlet syndrome

We discuss MRI findings in patients with thoracic outlet syndrome (TOS). A total of 100 neurovascular bundles were evaluated in the interscalene triangle (IS), costoclavicular (CC), and retropectoralis minor (RPM) spaces. To exclude neurogenic abnormality, MRIs of the cervical spine and brachial plexus (BPL) were obtained in neutral. To exclude compression on neurovascular bundles, sagittal T1W images were obtained vertical to the longitudinal axis of BPL from spinal cord to the medial part of the humerus, in abduction and neutral. To exclude vascular TOS, MR angiography (MRA) and venography (MRV) of the subclavian artery (SA) and vein (SV) in abduction were obtained. If there is compression on the vessels, MRA and MRV of the subclavian vessels were repeated in neutral. Seventy-one neurovascular bundles were found to be abnormal: 16 arterial-venous-neurogenic, 20 neurogenic, 1 arterial, 15 venous, 8 arterial-venous, 3 arterial-neurogenic, and 8 venous-neurogenic TOS. Overall, neurogenic TOS was noted in 69%, venous TOS in 66%, and arterial TOS in 39%. The neurovascular bundle was most commonly compressed in the CC, mostly secondary to position, and very rarely compressed in the RPM. The cause of TOS was congenital bone variations in 36%, congenital fibromuscular anomalies in 11%, and position in 53%. In 5%, there was unilateral brachial plexitis in addition to compression of the neurovascular bundle. Severe cervical spondylosis was noted in 14%, contributing to TOS symptoms. For evaluation of patients with TOS, visualization of the brachial plexus and cervical spine and dynamic evaluation of neurovascular bundles in the cervicothoracobrachial region are mandatory.

The radiologic relationship of the shoulder girdle to the thorax as an aid in diagnosing neurogenic thoracic outlet syndrome

PURPOSE

Neurogenic thoracic outlet syndrome (NTOS) is produced by compression of the brachial plexus in the thoracic outlet. The lower position of the shoulder girdle relative to the upper thorax may be related to NTOS. We investigated this hypothesis using plain cervical radiographs.

METHODS

We conducted this case-control study using plain cervical anteroposterior and lateral radiographs in 63 NTOS patients and 126 carpal tunnel syndrome patients who were matched for age and sex. To estimate the position of the shoulder girdle relative to the upper thorax, we analyzed the level of the clavicle using 2 parameters: the number of vertebrae visible in a lateral radiograph and the number of vertebrae above the line connecting both sternal ends of the clavicles in an anteroposterior radiograph. The number of vertebrae visible in a lateral radiograph was the parameter for the level of the lateral part of the clavicle relative to the upper thorax, whereas we used the number of vertebrae above the line connecting both sternal ends of the clavicles in an anteroposterior radiograph to determine the level of the medial part of the clavicle.

RESULTS

Both parameters were greater in the NTOS group than in the control group, which suggests that the level of the shoulder girdle was lower in the NTOS group than in the control group. In addition, the risk of NTOS was increased in patients with lower shoulder girdle position.

CONCLUSIONS

The lower placement of the shoulder girdle relative to the upper thorax was related to NTOS. Physicians may be able to estimate the position of the shoulder girdle using plain cervical radiographs when NTOS is clinically suspected.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic IV.

Between a rock and a hard place: clinical and imaging features of vascular compression syndromes

Vascular compression syndromes are caused by the entrapment of vessels between rigid or semirigid surfaces in a confined anatomic space. Chronic entrapment may lead to arterial ischemia and embolism, venous stasis and thrombosis, and hematuria. These syndromes are usually seen in otherwise healthy young patients, among whom underdiagnosis is common. Most occurrences of vascular compression are associated with an underlying anatomic abnormality. In a small percentage of cases, other contributing factors, including repetitive microtrauma, may cause pathologic changes leading to the onset of pain and other symptoms of vascular and neural compression. Hence, the diagnosis must be based on both clinical and radiologic findings. Because some cases of vascular entrapment become symptomatic only when specific physical maneuvers are performed, dynamic diagnostic imaging methods are especially useful. Digital subtraction angiography has been the mainstay of imaging-based diagnosis for most vascular compression syndromes, but other methods (eg, color Doppler ultrasonography, computed tomographic angiography, and magnetic resonance angiography) are used with increasing frequency for initial diagnostic evaluation. Because vascular compression syndromes are caused by the external compression of vessels, endoluminal treatment alone is rarely adequate and surgical decompression is likely to be required for optimal and durable clinical benefit. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.321115011/-/DC1.

Clavicle-induced narrowing of the thoracic outlet during shoulder abduction as imaged by computed tomographic angiography and enhanced by three-dimensional reformation

OBJECTIVE

This study aimed to confirm the location and degree of compromise of the subclavian vessels within the thoracic outlet during ipsilateral arm abduction in patients with clinical evidence of thoracic outlet syndrome and to identify both the physical and physiologic source of neurovascular compromise that induces the symptoms of thoracic outlet syndrome.

DESIGN

After a neuromuscular and vascular examination, all of the subjects underwent a two-part high-resolution computed tomographic angiography with three-dimensional reformation. The initial study was performed with the arm held at the side in an anatomical neutral position. Subsequently, the arm was abducted to 90 degrees with external rotation (ABER). In each position, 60 ml of iodinated nonionic contrast medium was injected in the opposite arm at 4 ml/sec. Three-dimensional volume-rendered images were obtained. Each image was subsequently reviewed by a musculoskeletal radiologist (S. Yadavalli). Patients were initially evaluated in the physiatrist's private office (M.M. LaBan). The computed tomographic scans were obtained from the participants as outpatients in an academic community-based medical center (William Beaumont Hospital). Seventeen outpatients with clinical signs and symptoms of thoracic outlet syndrome were evaluated, including seven men and ten women. This group has an average age of 48 yrs (range, 17-73 yrs).

RESULTS

The level of vessel occlusion varied in the costoclavicular space as well as in demonstrating the alterations in the diameter of both the subclavian artery and vein both in the neutral and ABER positions. The possible levels of occlusions included the costoclavicular space, the interscalene triangle, and the retropectoralis minor space. The narrowing of the subclavian vessel was considered significant if the percentage change of the vessel's diameter between the neutral and the ABER positions was 30% or greater for the subclavian artery and 50% or greater for the subclavian vein.

CONCLUSIONS

The average change in the costoclavicular space between the neutral and ABER positions was 18.2 mm or 55.6%. The degree of subclavian artery occlusion was significant in 8 (47%) of the 17 patients. The average change in artery diameter was 28% (5.5 to 7.5 mm). Significant subclavian vein occlusion was present in 12 (75%) of 16 patients. The average change in venous diameter was 54.1% (5.7 to 12.6 mm). In two cases, venous occlusion occurred in the retropectoralis minor space, one of which was significant at 79%. The vast majority of patients, that is, 13 (76.5%) of 17, demonstrated a compression of either the subclavian vein or artery, whereas 6 (35.3%) of 17 demonstrated a compression in both. In each of these cases, the asymptomatic side failed to demonstrate a significant change in either the venous and/or arterial caliber.

Single CT-guided chemodenervation of the anterior scalene muscle with botulinum toxin for neurogenic thoracic outlet syndrome

OBJECTIVE

To examine pain relief in patients with neurogenic thoracic outlet syndrome (NTOS) after a single, low dose injection of botulinum toxin A (Botox) into the anterior scalene muscle (ASM) under computed tomographic (CT) guidance.

DESIGN

Prospective longitudinal study.

SETTING

Academic medical institution.

PATIENTS

Patients 18 years of age and older were evaluated for potential scalenectomy and first rib resection using the transaxillary approach at the study institution between 2005 and 2008. All patients had failed physical therapy. A total of 29 procedures on 27 participants were studied.

INTERVENTIONS

A single, 20-unit injection of Botox into the ASM under CT-guidance.

OUTCOME MEASURES

Short-form McGill Pain Questionnaire (SF-MPQ) prior to and at 1, 2, and 3 months post-Botox toxin injection.

RESULTS

There was a decline in pain during the 3 months subsequent to Botox injection as noted by the following components of the SF-MPQ: sensory (P = 0.02), total (P = 0.05), visual analog scale (VAS [P = 0.04]), and present pain intensity (PPI) score (P = 0.06). The proportion of patients reporting more intense pain scores did not return to the pre-intervention level at 3 months post-Botox injection.

CONCLUSION

Patients experienced substantial pain relief in months 1 and 2 following a single Botox injection into the ASM under CT guidance. Significant pain reduction was noted for 3 months after Botox injection with respect to both sensory and VAS scores, and the total and PPI scores approximated statistical significance. After 3 months, patients experienced a 29% decrease in the sensory component of their pain as well as an approximate 15% reduction in their VAS score. A single, CT-guided Botox injection into the ASM may offer an effective, minimally invasive treatment for NTOS.

Multidetector computed tomography pulmonary angiography: does arm position affect pulmonary artery enhancement?

OBJECTIVE

To evaluate whether arm position affects pulmonary artery enhancement in computed tomographic pulmonary angiography (CTPA).

METHODS

Study protocol had local ethics committee approval. Eighty-six patients who received 16 detector row CTPA for suspected pulmonary embolism were scanned with their contrast-injected arm resting at their side and compared with 94 patients who were scanned with both arms resting above their head. Two radiologists assessed pulmonary artery enhancement with a region-of-interest measurement of the main pulmonary artery density, scored the degree of beam-hardening artifact arising from the superior vena cava (SVC) and from the dependent arm that crossed the pulmonary arteries (1 = no artifact, 5 = artery obscured), and measured the degree of central venous compression of the injected veins at the thoracic inlet. A 2-tailed t test was performed to compare pulmonary artery density and central venous compression.

RESULTS

There was no difference in pulmonary artery enhancement between the 2 arm positions. Mean density of contrast in the main pulmonary artery was 329 Hounsfield units (HU) (95% confidence interval (CI), 310-350) in the arm-down group, compared with 325 HU (95% CI, 306-346) in the arm-up group (P = 0.65). Greater compression of the central veins occurred in the arm-up group (48.5%; 95% CI, 42.3%-54.8%) than in the arm-down group (22.3%; 95% CI, 16.8%-27.8%) (P < 0.05). There was also more beam hardening arising from contrast in the SVC in the arm-up group (P < 0.0001).

CONCLUSIONS

Arm position does not affect pulmonary arterial enhancement during CTPA. There was greater central venous compression and more beam-hardening artifact arising from the SVC when the arm was held above the head.

The Relationship Between Magnetic Resonance Imaging Findings and Postural Maneuver and Physical Examination Tests in Patients With Thoracic Outlet Syndrome: Results of a Double-Blind, Controlled Study

OBJECTIVES

To investigate the differences in findings from magnetic resonance imaging (MRI) in the neutral and provocative positions, and to examine the relationship between these differences and the results of physical examination tests in patients with thoracic outlet syndrome (TOS).

DESIGN

Prospective.

SETTING

University physical medicine and rehabilitation outpatient and radiology clinics.

PARTICIPANTS

Twenty-nine patients and 12 healthy controls. All of the patients had positive bilateral TOS stress tests; control group participants were symptom free and had negative TOS stress tests bilaterally.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

All participants underwent Adson's test, the Halsted maneuver, and a hyperabduction test. All were evaluated with MRI while in 2 positions: the neutral position (upper extremities adducted) and in a provocative position. Measurements were obtained at the interscalene triangle, at the costoclavicular space, and at the retropectoralis minor space.

RESULTS

There was a significant difference in MRI findings between the neutral and provocative position in the patients (P<.05), but there were no significant differences in the control group. There was a significant difference in the positional change values in MRI between the patients and the control subjects (P<.05). The difference was found in the minimum costoclavicular distance between patients with a positive Halsted maneuver and a negative Halsted maneuver (P<.05).

CONCLUSIONS

Our findings indicate that MRI findings in patients in a provocative position are more valuable in the diagnosis of TOS, and these findings are in accord with findings from the physical evaluation tests.

Imaging assessment of thoracic outlet syndrome

The thoracic outlet includes three compartments (the interscalene triangle, costoclavicular space, and retropectoralis minor space), which extend from the cervical spine and mediastinum to the lower border of the pectoralis minor muscle. Dynamically induced compression of the neural, arterial, or venous structures crossing these compartments leads to thoracic outlet syndrome (TOS). The diagnosis is based on the results of clinical evaluation, particularly if symptoms can be reproduced when various dynamic maneuvers, including elevation of the arm, are undertaken. However, clinical diagnosis is often difficult; thus, the use of imaging is required to demonstrate neurovascular compression and to determine the nature and location of the structure undergoing compression and the structure producing the compression. Cervical plain radiography should be performed first to assess for bone abnormalities and to narrow the differential diagnosis. Computed tomographic (CT) angiography or magnetic resonance (MR) imaging performed in association with postural maneuvers is helpful in analyzing the dynamically induced compression. B-mode and color duplex ultrasonography (US) are good supplementary tools for assessment of vessel compression in association with postural maneuvers, especially in cases with positive clinical features of TOS but negative features of TOS at CT and MR imaging. US may also allow analysis of the brachial plexus. However, MR imaging remains the method of choice when searching for neurologic compression.

Ultrasonographic assessment of arterial cross-sectional area in the thoracic outlet on postural maneuvers measured with power Doppler ultrasonography in both asymptomatic and symptomatic populations

OBJECTIVE

The purpose of this study was to evaluate the feasibility and potential usefulness of power Doppler ultrasonography (PDU) in the assessment of changes in arterial cross-sectional area in the thoracic outlet during upper limb elevation.

METHODS

Forty-four volunteers and 28 patients with a clinical diagnosis of arterial thoracic outlet syndrome were evaluated by B-mode imaging and PDU. Arterial cross-sectional area was assessed in the 3 compartments of the thoracic outlet with the arm alongside the body and at 90 degrees, 130 degrees, and 170 degrees of abduction. The percentage of arterial stenosis was calculated for each of these arm positions. Nineteen of the 28 patients were also assessed by magnetic resonance (MR) imaging.

RESULTS

No significant arterial stenosis was shown in the interscalene triangle and in the retropectoralis minor space of the volunteers and patients. A significant difference (P < .01) in stenosis between volunteers and patients was seen for all degrees of abduction in the costoclavicular space. The 130 degrees hyperabduction maneuver appeared to be the most discriminating postural maneuver. Seven patients assessed with MR imaging did not have any arterial stenosis on MR images, whereas an appreciable degree of arterial stenosis was shown with ultrasonography.

CONCLUSIONS

Arterial compression inside the thoracic outlet can be detected and quantified with B-mode imaging in association with PDU.

Evaluation of MR angiographic technique in the assessment of thoracic outlet syndrome

AIM

To evaluate two-dimensional time of flight (2D TOF) and three-dimensional contrast-enhanced magnetic resonance angiographic (3DCE MRA) techniques in the assessment of patients with suspected thoracic outlet syndrome (TOS) of vascular origin.

MATERIALS AND METHODS

Fifty-five consecutive examinations, in 51 patients with suspected TOS of vascular origin, were examined using either a 1T or 1.5T Siemens magnetic resonance imaging (MRI) unit, using either 2D TOF (n=13) or 3DCE MRA (n=42). Examinations were performed with the arms abducted (n=27) or both abducted and adducted (n=28). The source images and MIPs were reviewed retrospectively and assessed for image quality and the presence of significant persistent stenosis or impingement (a >60% reduction in the diameter of the subclavian vessels at the thoracic outlet or evidence of post-stenotic dilatation). When significant impingement was identified, the images were reformatted with multiplanar reconstruction to determine the cause.

RESULTS

Images were sub-optimal in 53% 2D TOF and 10% 3DCE MRA examinations. 3DCE MRA offered vessel coverage from the aortic arch to the distal axilliary arteries, whereas, 2D TOF sequences gave more limited coverage. Eight patients were found to have significant impingement (n=7) or stenosis (n=1) of the subclavian artery attributable to TOS. 3DCE MRA also demonstrated other relevant significant stenoses not attributable to TOS (n=5). All cases of impingement were either seen only, or more prominently, on sequences with the arms abducted. Reformatting the 3DCE MRA studies demonstrated the cause of impingement.

CONCLUSIONS

Both 2D TOF and 3DCE MRA may demonstrate TOS with significant arterial impingement. In comparison with 2D TOF sequences, 3DCE MRA offers extensive vessel coverage, is less prone to artefact and frequently demonstrates the underlying cause of TOS when studies are reformatted. Evidence of impingement should be sought from sequences performed with the arms abducted and venous phase sequences may show corroborative venous impingement.

Upper extremity deep venous thrombosis: interventional management

Upper extremity deep venous thrombosis, previously thought to be a relatively innocuous disorder in comparison to lower extremity deep venous thrombosis, has recently begun to receive the attention it merits. Its optimal management remains controversial despite the development of several new techniques and devices which allow more rapid removal of thrombus and treatment of underlying venous stenotic disease. The following article provides a framework to discuss its treatment, with the emphasis on endovascular management.

Thoracic outlet: assessment with MR imaging in asymptomatic and symptomatic populations

PURPOSE

To compare the dynamic modifications of the thoracic outlet in asymptomatic volunteers and symptomatic patients and assess the presence and location of vasculonervous compressions in these two populations.

MATERIALS AND METHODS

Thirty-five healthy volunteers and 54 patients with clinical symptoms of thoracic outlet syndrome (TOS) underwent magnetic resonance (MR) imaging of the thoracic outlets with their arms alongside their bodies and after a postural maneuver. Measurements were obtained at the interscalene triangle (thickness of anterior scalene muscle, interscalene angle), at the costoclavicular space (minimum costoclavicular distance, distance between inferior border of subclavius muscle and the anterior chest wall, maximum thickness of subclavius muscle, angle between first rib shaft and horizontal), and at the retropectoralis minor space (distance between posterior border of pectoralis minor muscle and posterior lining of axilla at the passage of the axillary vessels, thickness of pectoralis minor muscle). The presence and location of vasculonervous compressions were also assessed. Group data were analyzed with the Student t test.

RESULTS

Patients with TOS had a smaller costoclavicular distance after the postural maneuver (P <.001), a thicker subclavius muscle in both arm positions (P <.001), and a wider retropectoralis minor space after the postural maneuver (P <.001) than did volunteers. Venous compressions after the postural maneuver were observed in 47% of volunteers and 63% of patients at the prescalene space, in 54% of volunteers and 61% of patients at the costoclavicular space, and in 27% of volunteers and 30% of patients at the retropectoralis minor space. Arterial and nervous compressions, respectively, were seen in 72% and 7% of patients. No arterial or nervous compression was seen in volunteers. Except for venous thrombosis, vasculonervous compressions were demonstrated only with arm elevation. Only three thoracic outlet measurements differed significantly in both populations.

CONCLUSION

MR imaging appeared helpful in demonstrating the location and cause of arterial or nervous compressions.

Outcome after thrombolysis and selective thoracic outlet decompression for primary axillary vein thrombosis

PURPOSE

Treatment for primary subclavian-axillary vein thrombosis (SAVT) at our institution consists of thrombolysis and anticoagulation for 3 months. Thoracic outlet decompression has been performed for a small number of patients. We wanted to review the functional outcomes of patients treated in such a manner.

MATERIAL AND METHODS

The records of all patients treated for a first episode of SAVT at our hospital over the past 10 years were reviewed. Demographics, comorbidities, method of diagnosis, and treatment for SAVT were recorded. Long-term follow-up was obtained by chart review and asking patients to complete the DASH (disabilities of the arm, shoulder and hand) questionnaire that was developed by the American Academy of Orthopedic Surgeons.

RESULTS

Twenty-eight patients, 20 men and eight women, with a mean age of 36 were treated during the study period. The median time between onset of symptoms and treatment was 5.5 (range, 1-100) days. All patients had confirmation of the diagnosis by venography. Twenty-five patients received thrombolytic treatment with catheter-directed infusions of urokinase; in the other three patients the vein was chronically occluded. Twelve patients had some degree of residual stenosis and were treated with percutaneous transluminal angioplasty after thrombolysis. During the study period two patients underwent decompressive surgery. Twenty-one patients responded to the DASH questionnaire a mean of 2.9 years (range, 2 months to 8 years) after the episode of SAVT. Six (28%) of 21 patients were completely symptom free, 13 patients (62%) had DASH scores consistent with mild symptoms, and two patients had more severe symptoms. Twenty percent (4 of 21) of patients report some difficulty with work.

CONCLUSIONS

Thrombolysis, followed by selective thoracic outlet decompression on the basis of the severity of patients' symptoms can be used as a therapeutic approach to SAVT without undue morbidity. The DASH questionnaire is a useful tool to evaluate results after therapy for SAVT.