Anomalies at the thoracic outlet are frequent in the general population

Don't be perplexed by the plexus! A practical approach to brachial plexus ultrasound

Ultrasound is as accurate as MRI in the detection of most brachial pathologies but tends to be underutilized in clinical practice compared to MRI. The main reason for this under-usage is a relative lack of knowledge regarding how to perform brachial plexus ultrasound and a lack of awareness of the ultrasound appearances of brachial pathologies. This review serves to re-address this imbalance by providing a practical overview on how to perform brachial plexus ultrasound as well as highlighting the ultrasound appearances of common pathologies likely to be encountered in everyday clinical practice.

Participation of Arterial Ischemia in Positional-Related Symptoms among Patients Referred for Thoracic Outlet Syndrome

Objectives: The coexistence of arterial compression with neurogenic thoracic outlet syndrome (TOS) is associated with a better post-surgical outcome. Forearm transcutaneous oxygen pressure (TcpO2) using the minimal decrease from rest of oxygen pressure (DROPmin) can provide an objective estimation of forearm ischemia in TOS. We hypothesized that a linear relationship exists between the prevalence of symptoms (PREVs) and DROPmin during 90° abduction external rotation (AER) provocative maneuvers. Thereafter, we aimed to estimate the proportion of TOS for which arterial participation is present. Methods: Starting in 2019, we simultaneously recorded forearm TcpO2 recordings (PF6000 Perimed®) and the presence/absence of ipsilateral symptoms during two consecutive 30 s AER maneuvers for all patients with suspected TOS. We retrospectively analyzed the relationship between the prevalence of symptoms and DROPmin results. We estimated the number of cases where ischemia likely played a role in the symptoms, assuming that the relationship should start from zero in the absence of ischemia and increase linearly to a plateau of 100% for the most severe ischemia. Results: We obtained 2560 TcpO2 results in 646 subjects (69% females). The correlation between PREVs and DROPmin was 0.443 (p < 0.001). From these results, we estimated the arterial participation in TOS symptoms to be 22.2% of our 1669 symptomatic upper limbs. Conclusions: TcpO2 appears to be an interesting tool to argue for an arterial role in symptoms in TOS. Arterial participation is frequent in TOS. Whether DROPmin could predict treatment outcomes better than the sole presence of compression is an interesting direction for the future.

Trans-axillary thoracic outlet decompression

Thoracic outlet syndrome (TOS) is a group of conditions thought to be caused by the compression of neurovascular structures going to the upper extremity. TOS is a difficult disease to diagnose, and surgical treatment remains challenging. Many different surgical techniques for the treatment of TOS have been described in the literature and many reasonable to good outcomes have been reported, which makes it hard for surgeons to determine which techniques should be used. Our aim was to describe the rationale, techniques, and outcomes associated with the surgical treatment of TOS. Most patients in our center are treated primarily through a trans-axillary approach. We will elaborate on the technical details of performing trans-axillary thoracic outlet decompression. The essential steps during surgery are illustrated with videos. We focused on the idea behind performing a trans-axillary thoracic outlet decompression in primary cases. Institutional data on the outcomes of this surgical approach are described briefly.

Supraclavius muscle observed during anterior scalenectomy for thoracic outlet syndrome: A report of two cases and review of the literature

Background

Thoracic outlet syndrome (TOS) is a clinical diagnosis caused by compression of neurovascular structures in the thoracic outlet. There are a variety of structures that cause compression implicated in TOS. TOS patients frequently require surgical decompression. Various structural anomalies encountered during decompression have been reported in the literature.

Case Description

We present two females (ages 42 and 45) that each underwent anterior scalenectomy for thoracic outlet decompression through a supraclavicular approach. A supraclavius muscle anomaly was observed in both patients. Analogous to the two reports previously described in the literature, the muscle inserted, along the medial superior undersurface of the clavicle and originated dorsally along the trapezius muscle. This is not to be confused with the subclavius posticus muscle, which originates from the first rib and inserts on the upper border of the scapula.

Conclusion

These two cases represent just the third and fourth ever descriptions of a supraclavius muscle anomaly encountered during TOS surgery. Due to the wide variety of anatomical variations encountered during TOS surgery, it is not only crucial for continued reporting of such anatomical variations to be reported in the literature but equally important for clinicians that treat TOS to be aware of such variations.

Comparison of duplex ultrasound and hemodynamic assessment with computed tomography angiography in patients with arterial thoracic outlet syndrome

Thoracic outlet syndrome (TOS) presents with a variety of neurovascular symptoms, and its diagnosis cannot be established purely on the basis of clinical assessments. Computed tomography angiography (CTA) is currently the most useful investigative modality for patients with suspected vascular TOS. However, CTA facilities are limited, and CTA itself is an expensive and a resource-intensive technique associated with risks such as radiation exposure and contrast toxicity. Therefore, a screening test to identify the need for CTA may facilitate clinical management of patients with suspected TOS. Data for patients with suspected arterial TOS who underwent duplex ultrasound with arterial hemodynamic assessment (HDA) (pulse-volume recording and Doppler arterial pressure measurement) at King Saud University Medical City Vascular Lab between 2009 and 2018 were collected. The sensitivity, specificity, positive and negative predictive values (NPV), and area under the curve for duplex ultrasound and arm arterial HDA with CTA were reviewed. The data for 49 patients (mean age, 31 ± 14 years) were reviewed, of which 71% were female. The sensitivity, specificity, positive predictive value, and NPV of duplex ultrasound were 86.7%, 49.3%, 26.5%, and 94.6%, respectively. For arm arterial HDA, these values were 73.3%, 78.9%, 42.3%, and 93.3%, respectively. The combination of arm arterial HDA with duplex ultrasound scores yielded sensitivity, specificity, positive predictive value, and NPV of 93.3%, 42.3%, 25.5%, and 96.8%, respectively. The combination of duplex ultrasound with arm arterial HDA showed higher sensitivity and NPV than either test alone. The specificity of arm arterial HDA was significantly higher than that of the other measurements. When suspected, arterial TOS could be ruled out using duplex ultrasound and arm arterial HDA. These 2 investigations may help determine the need for CTA.

Combined nerve and vascular ultrasound in thoracic outlet syndrome: A sensitive method in identifying the site of neurovascular compression

We investigated the diagnostic utility of combined nerve and vascular ultrasound in thoracic outlet syndrome (TOS) in a retrospective cohort study on two sites, involving 167 consecutive patients with the clinical symptoms suggestive of neurogenic and/or vascular TOS, and an age- and sex-matched control group. All patients and control subjects underwent nerve ultrasound of the supraclavicular brachial plexus to look for fibromuscular anomalies / compression of the brachial plexus in the scalenic region, and vascular ultrasound of the infraclavicular subclavian artery with the arm in neutral and abducted position, serving as an indicator for costoclavicular compression of the neurovascular bundle. Based on clinical symptoms, neurogenic TOS (81%) was the most frequent type of TOS, followed by combined neurogenic and arterial TOS (8%). The frequency of abnormal nerve and/or vascular ultrasound findings differed significantly from the control group (P<0.00001). The pooled sensitivity was 48% for nerve ultrasound, 85% for vascular ultrasound, and 94% when combined. Among the findings, the fibromuscular ‘wedge-sickle sign’, indicating compression of the lower trunk in the scalenic region by a congenital fibromuscular anomaly (e.g. Roos ligaments), showed the highest specificity (100%). A bony ‘wedge-sickle sign’ was also delineated, where lower trunk compression is caused by the neck of the 1^st rib. As implied by the higher sensitivity of vascular ultrasound, the most common site of compression was the costoclavicular space, but multilevel compression was also frequently observed. In summary, combined nerve and vascular ultrasound is a sensitive and reliable method to support the diagnosis of TOS. It can also identify the site(s) of compression, with obvious therapeutic consequences.

High-Resolution Ultrasound and Magnetic Resonance Imaging of Abnormal Ligaments in Thoracic Outlet Syndrome in a Series of 16 Cases

Introduction

Neurogenic thoracic outlet syndrome (NTOS) is a complex entity that comprises various clinical presentations, which are all believed to result from mechanical stress to the brachial plexus. Causes for the stress can include fibrous bands, spanning from the transverse processes, stump, or cervical ribs to the pleural cupula. The aim of this case series is to document how the combined potential of high-resolution neurography, including high-resolution ultrasound (HRUS), and magnetic resonance imaging (MRI) can be used to identify, anatomical compression sites, such as stump ribs and their NTOS associated ligamentous bands.

Materials and Methods

Retrospective chart and image reviews identified patients, who underwent HRUS between 2011 and 2021 and the diagnosis of NTOS caused by accessory ligaments was subsequently confirmed by radiological imaging (MRI) and/or surgical exploration.

Results

Sixteen patients were included in this study. In all cases, a ligament extending from the tip of a stump rib to the pleural cupula could be depicted. In all cases, these structures led to compression of the lower trunk of the brachial plexus. All surgically explored cases confirmed the radiological findings.

Conclusion

This case-series demonstrates that HRUS and MRI can directly and reliably visualize accessory costocupular ligaments and a stump rib in patients with symptoms of NTOS. HRUS may be used as the first imaging modality to diagnose suspected NTOS.

Paralysis of the Upper Extremity Due to Acute Thoracic Outlet Syndrome Caused by the Subclavius Posticus Muscle: A Case Report With Literature Review

The subclavius posticus muscle is a rare aberrant muscle that traverses from the costal cartilage of the first rib posterolaterally to the superior border of the scapula. We report a patient having persistent paralysis of shoulder abduction with wrist and finger extension after a humeral neck fracture. Electromyography (EMG) examination revealed injuries to several upper extremity peripheral nerves, including the radial, axillary, and musculocutaneous nerves. Magnetic resonance imaging (MRI) performed at 10 months post-injury showed severe entrapment of the left brachial plexus by the subclavius posticus muscle at the thoracic outlet. The diagnosis of brachial plexus injury due to a rare abnormal subclavius posticus muscle was typically delayed until the MRI was performed for unexplained multiple peripheral nerve palsy. Resection of the aberrant muscle and brachial plexus decompression did not yield significant improvement in the patient’s radial nerve palsy until 6 months after surgery. Entrapment of the brachial plexus caused by the subclavius posticus muscle can cause symptoms of acute thoracic outlet syndrome following trauma to the upper extremity. In a case of inexplicable multiple peripheral nerve injuries in the upper extremity that are not proportional to the degree of trauma, MRI imaging along with EMG is required.

Doppler waveform analysis during provocative manoeuvres in the assessment for arterial thoracic outlet syndrome results in high false-positive rates; a cross-sectional study

Objectives

There is a high rate of false-positive arterial Thoracic Outlet Syndrome (ATOS) diagnoses due to limited research into the optimal use of ultrasound. To improve future diagnostic efficiency, we aimed to characterise the haemodynamic effects of different provocative positions and estimate the prevalence of compression in the healthy population.

Design

In this cross-sectional, observational study, the effect of varying degrees of arm abduction on discomfort levels and/or changes in subclavian artery Doppler waveform was analysed in the healthy population; the peak systolic velocity (PSV), systolic rise time (SRT), phasicity and extent of turbulence were recorded.

Setting

Department of the Vascular Studies, Royal Free Hospital.

Participants

19 participants (11 females, 27.4 ± 5.2 years) were recruited for bilateral scans.

Main outcome measures

Seven positions were investigated; the primary outcome was an occlusion or monophasic waveform indicating significant compression and this was compared with the secondary outcome; any physiological discomfort.

Results

28.9% experienced significant arterial compression in at least one position; 120° abduction was the position with the greatest level of abduction that did not result in significant waveform changes or symptoms. The PSV and SRT were difficult to accurately measure and bore no correlation to the level of compression.

Conclusion

Ultrasound testing in isolation would result in a false indication of TOS in almost 30% of our normal population. With further research, the 120° abduction position may have a lower false-positive rate. The PSV and SRT must be interpreted with caution due to their variability even within the healthy population.

Comparison of transcutaneous oximetry with symptoms and arteriography in thoracic outlet syndrome

BACKGROUND

Non-invasive tests are still required to improve the holistic diagnostic approach of thoracic outlet syndrome (TOS).

OBJECTIVES

We aimed to analyze the diagnostic accuracy of the decrease from rest oxygen pressure (DROP) index of transcutaneous oximetry (TcpO2) in TOS.

METHODS

Seventy-six patients and 40 asymptomatic volunteers (Controls) were enrolled. In TOS-suspected patients, the arteriograms were investigated for the presence of≥75% stenosis. The area under receiver operating characteristics curve (AUC) analysis tested the ability of forearm TcpO2 during provocative maneuvers to discriminate patients from controls and, to predict a positive arteriographic findings in the 44 TOS-suspected patients that had an arteriography.

RESULTS

The media [25/75° centile] DROP values of controls and patients were -14 [-8/-22] mmHg and -22 [-12/-42] mmHg, respectively (p for Mann-Whitney<0.02). AUC analysis showed a significant ability of TcpO2 to predict the presence of subclavian arterial compression on arteriography (AUC, 0.694).

CONCLUSIONS

Although time consuming, tcpO2 is independent of the observer expertise and could be useful in TOS-suspected patients to select the patients that should undergo arteriography.

Diagnostic Accuracy of Clinical Tests for Neurogenic and Vascular Thoracic Outlet Syndrome: A Systematic Review

OBJECTIVE

To summarize the evidence on the accuracy of clinical tests to help confirm or refute a diagnosis of thoracic outlet syndrome (TOS).

METHODS

We searched 10 databases (January 1990 to February 2016) using relevant key words and medical subject headings terms. We considered diagnostic test accuracy studies comparing clinical tests for the diagnosis of TOS against a reference test. Cross-sectional, cohort, and case-control studies and randomized controlled trials were included. Risk of bias was appraised using QUADAS-2 and the Quality Appraisal of Reliability Studies checklist. We performed a qualitative synthesis of scientifically admissible studies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline was used to report findings.

RESULTS

A total of 3932 articles were retrieved. After removal of duplicates, 1767 articles were screened for titles and abstract, leaving 494 articles for full-text review. Ten studies met the eligibility criteria and were assessed for risk of bias, 4 of which were included in the review. None of the included studies used the same index tests when comparing with a gold standard, and quality was poor. High clinical heterogeneity and the use of different comparators prevented from pooling results. Findings suggest that prescribing magnetic resonance imaging during provocative positioning to confirm a diagnosis of TOS may be useful. However, this is associated with a high false-positive rate of venous compression.

CONCLUSION

Little evidence currently supports the validity of clinical tests for the diagnosis of TOS. Future diagnostic accuracy studies should aim to use established methodological criteria and appropriate reporting guidelines to help validate clinical tests for diagnosing patients with TOS.

Long-term functional outcomes after surgical treatment of nonspecific thoracic outlet syndrome: Retrospective study of 70 cases at a mean of 8 years' follow-up

Our objective was to study the clinical and functional outcomes after surgical treatment of nonspecific thoracic outlet syndrome (TOS) using a supraclavicular approach. We included every patient with TOS who was treated surgically by the same surgeon at a single hospital between 1999 and 2014 with a minimum follow-up of 4 years. The primary outcome was the overall evaluation of the function by the QuickDASH Score. Secondary outcomes included functional, subjective outcomes, pain levels, and neuropathic features. The clinical outcome of 70 cases was evaluated with a mean follow-up of 8.5 years. The improvement in the QuickDASH Score was significant with an average change of 38 points. Mean pain intensity was reduced postoperatively by 1.6 points from 5.1/10 to 3.5/10. Persistent pain rate at 4/10 or more remained in 56% of cases. These cases were mostly neuropathic. The surgical procedure significantly reduced the number of patients suffering from paresthesia, numbing or weakness. The possibility of sequelae and the persistence of neuropathic pain means the surgical indication should be limited to patients with significant functional disability despite well-conducted rehabilitation. The long-term functional outcomes in patients undergoing TOS was mostly good but could be improved by addressing residual neuropathic pain symptoms.

Microvascular Response to the Roos Test Has Excellent Feasibility and Good Reliability in Patients With Suspected Thoracic Outlet Syndrome

Background: Exercise oximetry allows operator-independent recordings of microvascular blood flow impairments during exercise and can be used during upper arm provocative maneuvers.

Objective: To study the test-retest reliability of upper-limb oximetry during the Roos test in patients with suspected thoracic outlet syndrome (TOS).

Materials and Methods: Forty-two patients (28 men, 14 women; mean age: 40.8 years) were examined via transcutaneous oxygen pressure (TcpO2) recordings during two consecutive Roos tests in the standing position. The minimal decrease from rest of oxygen pressure (DROPmin) value was recorded after each maneuver was performed on both arms. The area under the receiver operating characteristic (ROC) curve defined the DROPmin diagnostic performance in the presence of symptoms during the tests. The Mann–Whitney U-test was used to compare the DROPmin in the symptomatic vs. asymptomatic arms. The test-retest reliability was analyzed with Bland-Altman representations. The results are presented as means ± standard deviations (SD) or medians [25–75 percentiles].

Results: The symptoms by history were different from the symptoms expressed during the Roos maneuvers in one-third of the patients. The DROPmin measurements were −19 [−36; −7] mmHg and −8 [−16; −5] mmHg in the symptomatic (n = 108) and asymptomatic (n = 60) arms, respectively. When TOS observed on ultrasound imaging was the endpoint, the area under the ROC curve (AUC) was 0.725 ± 0.058, with an optimal cutoff point of −15 mmHg. This value provided 67% sensitivity and 78% specificity for the presence TOS via ultrasound. When symptoms occurring during the test represented the endpoint, the AUC was 0.698 ± 0.04, with a cutoff point of −10 mmHg. This provided 62% sensitivity and 66% specificity for the presence of pain in the ipsilateral arm during the test. The test-retest reliability of DROPmin proved to be good but not perfect, partly because of unreliability of the provocation maneuvers.

Conclusion: To the best of our knowledge, this study is the first to investigate microvascular responses during the Roos maneuver in patients with suspected TOS. The presence of symptoms was significantly associated with ischemia. TcpO2 facilitated the recording of both macrovascular and microvascular responses to the Roos test. The Roos maneuver should probably be performed at least twice in patients with suspected TOS.

The importance of costoclavicular space on possible compression of the subclavian artery in the thoracic outlet region: a radio-anatomical study

OBJECTIVES

The purposes of this study were to identify possible compression points along the transit route of the subclavian artery and to provide a detailed anatomical analysis of areas that are involved in the surgical management of the thoracic outlet syndrome (TOS). The results of the current study are based on measurements from cadavers, computed tomography (CT) scans and dry adult first ribs.

METHODS

The width and length of the interscalene space and the width of the costoclavicular passage were measured on 18 cervical dissections in 9 cadavers, on 50 dry first ribs and on CT angiography sections from 15 patients whose conditions were not related to TOS.

RESULTS

The average width and length of the interscalene space in cadavers were 15.28 ± 1.94 mm and 15.98 ± 2.13 mm, respectively. The widths of the costoclavicular passage (12.42 ± 1.43 mm) were significantly narrower than the widths and lengths of the interscalene space in cadavers (P < 0.05). The average width and length of the interscalene space (groove for the subclavian artery) in 50 dry ribs were 15.53 ± 2.12 mm and 16.12 ± 1.95 mm, respectively. In CT images, the widths of the costoclavicular passage were also significantly narrower than those of the interscalene space (P < 0.05). The measurements from cadavers, dry first ribs and CT images were not significantly different (P > 0.05).

CONCLUSIONS

Our results showed that the costoclavicular width was the narrowest space along the passage route of the subclavian artery. When considering the surgical decompression of the subclavian artery for TOS, this narrowest area should always be kept in mind. Since measurements from CT images and cadavers were significantly similar, CT measurements may be used to evaluate the thoracic outlet region in patients with TOS.

Effort thrombosis of the subclavian artery as a consequence of a unique anomaly

Congenital anatomic anomalies and variations are frequent in the thoracic outlet and may be associated with clinical symptoms. Arterial thoracic outlet syndrome (TOS) is characterized by subclavian artery compression and vascular pathology, almost always in the presence of a bony abnormality. We describe here a patient with arterial thromboembolism following a fall on the outstretched arm, who was found to have subclavian artery stenosis and post-stenotic dilatation in the absence of a bony abnormality. Surgical exploration revealed a previously undescribed anomaly in which the subclavian artery passed through the costoclavicular space in front of the anterior scalene muscle, where it was subject to bony compression between the first rib and clavicle. Successful treatment was achieved by scalenectomy, first rib resection and interposition bypass graft reconstruction of the affected subclavian artery. This newly acknowledged anatomical variant adds to our understanding of the diverse factors that may contribute to development of TOS.

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.

Safety and Efficacy of Catheter-Directed Therapies as a Supplement to Surgical Decompression in Venous Thoracic Outlet Syndrome

OBJECTIVE

The purpose of this study is to evaluate the role of endovascular therapy in the management of venous thoracic outlet syndrome (TOS), with an emphasis on its role after surgical decompression.

MATERIALS AND METHODS

This single-center retrospective review identified all patients who underwent conventional contrast-enhanced venography as a component of the imaging evaluation of clinically suspected venous TOS from January 2004 through September 2015. Eighty-one patients were identified, with a mean (± SD) age of 33 ± 12 years, of whom 59% (48/81) were women. After imaging confirmation of venous TOS, a standardized treatment protocol combining surgical and endovascular intervention was used for management.

RESULTS

Of the 81 patients included in the study, 73 (90%) had angiographic evidence of venous TOS; 41 of these 73 patients (56%) underwent endovascular venous intervention (e.g., thrombolysis or angioplasty before surgical) decompression. A total of 67 patients (67/73; 92%) with venous TOS underwent surgical decompression, with 56 of these (56/73; 77%) undergoing postoperative venography. Of these 56 patients who underwent postoperative venography, 48 (86%) required venoplasty, four had normal-appearing subclavian veins (7%) and had no intervention, and four of 48 (8%) had chronic total venous occlusions that could not be recanalized. Only four of the 48 of the patients (8%) who underwent postdecompression venoplasty required subsequent repeat venography and intervention for management of persistent or recurrent symptoms, whereas all others (44/48; 92%) remained symptom free on clinical follow-up. No complications were identified that were related to the endovascular interventions.

CONCLUSION

Combining venography and endovascular venous intervention with surgical decompression in managing patients with clinically suspected venous TOS is safe and effective. Postdecompression venoplasty appears to be highly effective, with a low rate of symptom recurrence.

MRI of thoracic outlet syndrome in children

Thoracic outlet syndrome is caused by compression of the neurovascular bundle as it passes from the upper thorax to the axilla. The neurovascular bundle can be compressed by bony structures such as the first rib, cervical ribs or bone tubercles, or from soft-tissue abnormalities like a fibrous band, muscle hypertrophy or space-occupying lesion. Thoracic outlet syndrome commonly affects young adults but can be seen in the pediatric age group, especially in older children. Diagnosis is based on a holistic approach encompassing clinical features, physical examination findings including those triggered by various maneuvers, electromyography, nerve conduction studies and imaging. Imaging is performed to confirm the diagnosis, exclude mimics and classify thoracic outlet syndrome into neurogenic, arterial, venous or mixed causes. MRI and MR angiography are useful in this process. A complete MRI examination for suspected thoracic outlet syndrome should include the assessment of anatomy and any abnormalities using routine sequences, vessel assessment with the arms in adduction by MR angiography and assessment of dynamic compression of vessels with abduction of the arms. The purpose of this paper is to describe the anatomy of the thoracic outlet, causes of thoracic outlet syndrome, the MR imaging techniques used in its diagnosis and the principles of image interpretation.

Experimental study of brachial plexus and vessel compression: evaluation of combined central and peripheral electrodiagnostic approach

Introduction

We sought to investigate the reliability of a new electrodiagnostic method for identifying Electrodiagnosis of Brachial Plexus & Vessel Compression Syndrome (BPVCS) in rats that involves the application of transcranial electrical stimulation motor evoked potentials (TES-MEPs) combined with peripheral nerve stimulation compound muscle action potentials (PNS-CMAPs).

Results

The latencies of the TES-MEP and PNS-CMAP were initially elongated in the 8-week group. The amplitudes of TES-MEP and PNS-CMAP were initially attenuated in the 16-week group. The isolateral amplitude ratio of the TES-MEP to the PNS-CMAP was apparently decreased, and spontaneous activities emerged at 16 weeks postoperatively.

Materials and Methods

Superior and inferior trunk models of BPVCS were created in 72 male Sprague Dawley (SD) rats that were divided into six experimental groups. The latencies, amplitudes and isolateral amplitude ratios of the TES-MEPs and PNS-CMAPs were recorded at different postoperative intervals.

Conclusions

Electrophysiological and histological examinations of the rats’ compressed brachial plexus nerves were utilized to establish preliminary electrodiagnostic criteria for BPVCS.

A Fourteen-Year Experience with Vascular Anomalies Encountered during Transaxillary Rib Resection for Thoracic Outlet Syndrome

BACKGROUND

Transaxillary approach to first rib resection and scalenectomy (TAFRRS) is a well-established technique for treatment of thoracic outlet syndrome (TOS). Although anatomic features encountered during TAFRRS are in general constant, vascular anomalies may be encountered but have not been described to date. Herein we describe vascular abnormalities encountered during TAFRRS.

METHODS

We performed a retrospective review of a prospective practice database of 224 operations for TOS performed in 172 patients from March 2000 to March 2014. We excluded 10 patients with missing operative reports, 3 reoperations on the same patient, and 8 non-transaxillary resections. We recorded vascular anomalies identified in operative reports and reviewed computed tomography imaging to delineate the nature of these abnormalities.

RESULTS

The overall incidence of vascular anomalies was 11% (22 of 203 TAFRRS). Most patients with anomalies had venous TOS (vTOS) (9 patients, 41%), followed by 7 (32%) with neurogenic TOS (nTOS). The remainder of the patients had arterial TOS (aTOS) (6 patients, 27%). Seven patients (32%) had an abnormal subclavian artery (SCA) with 5 (23%) having an abnormal arterial course in the anterior scalene muscle (ASM); 6 patients (27%) had an abnormal internal mammary artery (IMA) originating from distal SCA; 4 (18%) had abnormalities in the supreme thoracic artery (bifurcation or duplication); 2 (9%) had an abnormal branch from the SCA with anomalous location in the operative field; and 3 (14%) had an abnormal large venous branch penetrating the ASM. In the 19 patients with arterial anomalies, 8 (42%) were recognized as arterial branches penetrating the ASM, and 11 (58%) were noticed as they had anomalous arterial locations within the operative field. Most arterial anomalies were seen in vTOS (9, 45%), followed by nTOS (7, 35%). No intraoperative vascular complications occurred. Perioperative complications included 1 occurrence of postoperative transfusion for bleeding following axillary drain discontinuation and 2 Horner's syndromes. One aberrant IMA was electively ligated to allow complete thoracic outlet decompression.

CONCLUSIONS

Arterial anomalies during TAFRRS are encountered in 11% of operations, and may present with vessel locations in unusual areas within the operative field, or as abnormal vessels penetrating the ASM, thus making scalenectomy precarious. Careful attention must be paid to possible abnormal locations of vessels in the thoracic outlet to avoid bleeding complications.

Thoracic outlet syndromes. The so-called "neurogenic types"

Neurogenic thoracic outlet syndrome (TOS) is one of the most controversial pain syndromes of the upper limbs. The controversies revolve around both the diagnosis and treatment of the non-specific or subjective subtypes. Their diagnosis rests on a combination of history, suggestive symptoms and clinical examination. Proximal pain is primarily muscular in origin, while distal symptoms may be the result of intermittent nerve compression and/or myofascial pain syndrome. Stringent clinical criteria are required to confirm the diagnosis of subjective TOS. In reality, multiple factors can be entangled, with TOS being one element within a multifactorial pain disorder; any musculotendinous pathology of the upper limb and any peripheral nerve entrapment require screening for potential concomitant TOS. Surgery is indicated in most cases of true neurogenic TOS, whereas rehabilitation is the standard treatment for subjective TOS.

The supraclavius muscle is a novel muscular anomaly observed in two cases of thoracic outlet syndrome

Various anomalous muscles and fibrofascial structures have been described in relation to the anatomy of thoracic outlet syndrome. We describe two patients with a previously undescribed muscle anomaly, which originated laterally near the trapezius muscle, coursed across the supraclavicular space deep to the scalene fat pad, and attached obliquely to the superior undersurface of the medial clavicle, which we have termed the “supraclavius” muscle. The significance of the supraclavius muscle is unknown, but its occurrence in patients with thoracic outlet syndrome indicates that it can be associated with narrowing of the anatomic space adjacent to the neurovascular structures.

Treatment for thoracic outlet syndrome

BACKGROUND

Thoracic outlet syndrome (TOS) is one of the most controversial diagnoses in clinical medicine. Despite many reports of operative and non-operative interventions, rigorous scientific investigation of this syndrome leading to evidence-based management is lacking. This is the first update of a review first published in 2010.

OBJECTIVES

To evaluate the beneficial and adverse effects of the available operative and non-operative interventions for the treatment of TOS a minimum of six months after the intervention.

SEARCH METHODS

On 23 June 2014 we searched the Cochrane Neuromuscular Disease Group Trials Specialized Register, CENTRAL, The Database of Abstracts of Reviews of Effects (DARE), MEDLINE, EMBASE, CINAHL Plus and AMED. We also searched reference lists of the identified trials.

SELECTION CRITERIA

We selected randomized or quasi-randomized studies involving participants with the diagnosis of TOS of any type (neurogenic, vascular, and 'disputed'), without limitations as to language of publication.We accepted studies that examined any intervention aimed at treating TOS.The primary outcome measure was change in pain rating, measured on a validated visual analog or similar scale at least six months after the intervention.The secondary outcomes were change in muscle strength, disability, experiences of paresthesias (numbness and tingling sensations), and adverse effects of the interventions.

DATA COLLECTION AND ANALYSIS

Three authors independently selected the trials to be included and extracted data. Authors rated included studies for risk of bias, according to the methods recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

This review was complicated by a lack of generally accepted criteria for the diagnosis of TOS and had to rely exclusively on the diagnosis of TOS by the investigators in the reviewed studies. We identified one study comparing natural progression with an active intervention. We found three randomized controlled trials (RCTs), but only two of them had a follow-up of six months or more, which was the minimum required follow-up for inclusion in the review. The first trial that met our requirements involved 55 participants with the 'disputed type' of TOS and compared transaxillary first rib resection (TFRR) with supraclavicular neuroplasty of the brachial plexus (SNBP). The trial had a high risk of bias. TFRR decreased pain more than SNBP. There were no adverse effects in either group. The second trial that met these requirements analyzed 37 people with TOS of any type, comparing treatment with a botulinum toxin (BTX) injection into the scalene muscles with a saline placebo injection. This trial had a low risk of bias. There was no significant effect of treatment with the BTX injection over placebo in terms of pain relief or improvements in disability, but it did significantly improve paresthesias at six months' follow-up. There were no adverse events of the BTX treatment above saline injection.

AUTHORS' CONCLUSIONS

This review was complicated by a lack of generally accepted diagnostic criteria for the diagnosis of TOS. There was very low quality evidence that transaxillary first rib resection decreased pain more than supraclavicular neuroplasty, but no randomized evidence that either is better than no treatment. There is moderate evidence to suggest that treatment with BTX injections yielded no great improvements over placebo injections of saline. There is no evidence from RCTs for the use of other currently used treatments. There is a need for an agreed definition for the diagnosis of TOS, especially the disputed form, agreed outcome measures, and high quality randomized trials that compare the outcome of interventions with no treatment and with each other.

Neurologic thoracic outlet syndrome: summarizing a complex history and evolution

Thoracic outlet syndrome (TOS) is a blanket term encapsulating many different clinical entities. Neurologic or neurogenic TOS (NTOS) is its main contributor, but it remains a complicated and sometimes controversial entity. NTOS incorporates numerous types, etiologies, clinical presentations, diagnostic findings, and therapeutic modalities. This article reviews the spectrum of disease within the thoracic outlet that affects the brachial plexus, with a special emphasis on the commonly afflicted sports medicine patient.

[Thoracic Outlet Syndrome: is it always a surgical condition? Analysis of a series of 31 cases operated by the supraclavicular route]

Introducción:

El síndrome de outlet torácico es una compresión del plexo braquial que suscita polémica. Se clasifica en Outlet Torácico Verdadero o neurogénico (OTV) y Outlet Torácico Disputado o no neurogénico (OTD). El primero presenta síntomas motores en la mano, mientras que el segundo sólo síntomas sensitivos en el miembro superior. El objetivo de este trabajo es analizar los resultados obtenidos en una serie de 31 cirugías.

Métodos:

Se analizaron las cirugías de nervios efectuadas entre 2003-2012, tomando los diagnósticos de outlet torácico cuyo período de seguimiento post-operatorio mínimo fuera de 6 meses. Se buscaron los siguientes datos: edad, sexo, presencia de síntomas sensitivos y/o motores, clasificación, resultado de los estudios neurofisiológicos y de imágenes, resultado de la cirugía, complicaciones post-operatorias y recidivas.

Resultados:

Se incluyeron 31 cirugías realizadas en 30 pacientes, 9 OTV (8 mujeres) de 24.3 años, y 21 con OTD (18 mujeres) de 37.4 años de edad en promedio. Un 90% presentaron alteraciones neurofisiológicas preoperatorias, y 66,6% imagenológicas. En el intraoperatorio, el 100% de los OTV presentó una alteración anatómica relacionada con la sintomatología, hecho observado sólo en el 36.7% de los OTD operados. El 87,5% de los OTV mejoraron sensitivamente, mientras que 77,7% mejoraron la atrofia. Por el contrario, 45.4% de los OTD mejoraron permanentemente, 36.3% no tuvieron cambios, 13.6% mejoraron transitoriamente y 4.5% (un caso) empeoró. Las complicaciones post-operatorias fueron más frecuentes aunque transitorias en el grupo de OTV (3 casos sobre 9 operados, 33.3%) que en los OTD (3 casos sobre 22, un 13.6%).

Conclusión:

El OTV suele mayormente mejorar luego de la cirugía, igual que el OTD aunque en una proporción mucho menor. Estos hallazgos coinciden con otros reportes recientes de esta patología.

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.

Anomalies of thoracic outlet in human fetuses: anatomical study

BACKGROUND

Thoracic outlet syndrome (TOS) identifies the clinical condition determined by the mechanical compression and entrapment of the subclavian vessels and the brachial plexus cords within the space delineated by the scalene muscles, the clavicle, and the first rib. To date, there are no concluding explanations concerning the real causes of the appearance of TOS in children. This is the first study to investigate the existence, frequency, and type of thoracic outlet anomalies in the prenatal stage (human fetuses).

METHODS

Eighty cervical dissections (40 consecutive spontaneously aborted human fetuses) were performed, and the musculoskeletal, vascular, and nervous elements that pass through the thoraco-cervico-axillary region were investigated.

RESULTS

Overall, anatomical anomalies of the thoraco-cervico-axillary region were found in 60% of the 80 cervical dissections. Nine (22.5%) of the 40 fetuses had normal bilateral anatomy. In 6.3%, the scalene hiatus had an oval shape due to the common costal insertion of the anterior and middle scalene muscles. Fibromuscular bands were found in 15% of the fetuses. Hypertrophy of the anterior scalene muscle was seen in 12.5% of the dissections. In 28.7% of the cervical dissections, hypertrophy of the C7 transversal process was noted, bilateral in seven cases. There was one case of a "C-shaped" clavicle anomaly. The absence of the internal mammary artery was noted in one case.

CONCLUSION

This study shows that the presence of TOS anomalies in fetuses is not a rare occurrence, emphasizing a pathological cervical background which can be harmful in situations of cervical trauma or inflammatory processes. Having knowledge of the types of anomalies which can lead to TOS is important for performing a complete surgical correction and avoiding the high failure rate of recurrent TOS.

Screening for head, neck, and shoulder pathology in patients with upper extremity signs and symptoms

NARRATIVE REVIEW: Conditions of the head, neck, thorax, and shoulder may occur simultaneously with arm pathology or produce symptoms perceived by the patient to originate in the elbow, wrist, or hand. Identification of the tissue disorder and associated impairments, followed by matching the rehabilitative intervention to address these issues, leads to optimal outcomes. With this goal in mind, the hand therapist needs to recognize clinical findings that signal potentially serious medical conditions of the brain, cervical region, chest, or shoulder. Additionally, less serious but potentially debilitating, musculoskeletal or neurogenic pain from proximal sources must also be differentiated from somatic pain originating in the elbow, wrist, or hand so that the clinician can decide to further examine and intervene or refer to an appropriate health care provider. This article describes clinical findings that suggest the presence of serious medical pathology in the head, neck, or thorax and presents a screening algorithm to assist in discriminating pain derived from local structures in the distal arm from referred pain originating in the more proximal regions of the shoulder, thorax, neck, or brain.

LEVEL OF EVIDENCE

5.

Treatment for thoracic outlet syndrome

BACKGROUND

Thoracic outlet syndrome (TOS) is one of the most controversial clinical entities in medicine. Despite many reports of operative and non-operative interventions, rigorous scientific investigation of this syndrome leading to evidence based management is lacking.

OBJECTIVES

To evaluate the beneficial and adverse effects of the available operative and non-operative interventions for the treatment of thoracic outlet syndrome.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Trials Specialized Register (July 2009), The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2009), MEDLINE (January 1966 to June 2009), EMBASE (January 1980 to June 2009), CINAHL (January 1981 to June 2009 ), AMED (January 1985 to June 2009 ) and reference lists of articles.

SELECTION CRITERIA

We selected randomized or quasi-randomized studies in any language of participants with the diagnosis of any type of thoracic outlet syndrome (neurogenic, vascular, and 'disputed'). The primary outcome measure was change in pain rating on a validated visual analog or similar scale at least six months after the intervention. The secondary outcomes were change in muscle strength and adverse effects of the interventions.

DATA COLLECTION AND ANALYSIS

Four authors independently selected the trials to be included and extracted data. The one included study was rated for risk of bias according to the methods recommended in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

This review was complicated by a lack of generally accepted criteria for the diagnosis of TOS and had to rely exclusively on the diagnosis of TOS by the investigators in the reviewed studies. There were no studies comparing natural progression with any active intervention. In one trial with a high risk of bias involving 55 participants transaxillary first rib resection decreased pain more than supraclavicular neuroplasty of the brachial plexus. There were no adverse effects in either group.

AUTHORS' CONCLUSIONS

This review was complicated by a lack of generally accepted diagnostic criteria for the diagnosis of TOS. There was very low quality evidence that transaxillary first rib resection decreased pain more than supraclavicular neuroplasty but no randomized evidence that either is better than no treatment. There is no randomized evidence to support the use of other currently used treatments. There is a need for an agreed definition for the diagnosis of TOS, especially the disputed form, agreed outcome measures and high quality randomized trials that compare the outcome of interventions with no treatment and with each other.

Measurement of subclavicular pressure on the subclavian artery and brachial plexus in the costoclavicular space during provocative positioning for thoracic outlet syndrome

BACKGROUND

Thoracic outlet syndrome is thought to be caused by compression of the brachial plexus or subclavian artery in the interscalene, costoclavicular, or subcoracoid space. Some provocative tests are widely used for diagnosing thoracic outlet syndrome. However, whether provocative positions actually compress the neurovascular bundle in these spaces remains unclear. The purpose of this study was to investigate the possibility of neurovascular bundle compression in the costoclavicular space by measuring the pressure applied to the brachial plexus and subclavian artery in provocative positions.

METHODS

Bilateral shoulders of eight fresh-frozen transthoracic human cadavers with no obvious anatomical abnormalities were used in this study. There were three female and five male cadavers with a mean age of 81.7 years (range 72-90 years). The pressure on the brachial plexus and subclavian artery between the clavicle and first rib were measured using a 0.13-mm thin pressure sensor in each of four provocative positions (depressed position, alternative Eden position, throwing position, Wright position).

RESULTS

Nerve contact pressure was increased in seven shoulders in the Wright position (2.87 +/- 3.13 N/cm(2); range 0.81-9.76 N/cm(2)). The frequency of nerve compression in the Wright position was significantly higher when compared to that in the other three limb positions (P = 0.018). Artery contact pressure was increased in three shoulders in the Wright position (mean 0.59 +/- 0.13 N/cm(2); range 0.45-0.7 N/cm(2)). As was the case with nerve compression, the frequency of compression tended to be higher for the Wright position, but no significant difference was seen.

CONCLUSIONS

In four of eight specimens with no obvious anatomical abnormalities, the brachial plexus was compressed in the costoclavicular space in the Wright position. The Wright position thus may be a useful position for inducing nerve compression in the costoclavicular space.

The prevalence of cervical ribs in a London population

Cervical ribs are an important cause of neurovascular compression at the thoracic outlet. Previous studies have shown the prevalence of cervical ribs to be between 0.05 and 3%, depending on the sex and race of the population studied. We examined 1,352 chest radiographs to determine the prevalence of cervical ribs in a London population of mixed sex and ethnicity. Our study found that the overall prevalence of cervical ribs was 0.74% with a higher rate in females compared with males (1.09 and 0.42%, respectively). Of the 10 individuals with a cervical rib, five were on the left, three were on the right and two were bilateral. The presence of elongated C7 transverse processes (transverse apophysomegaly) was also noted. We found a total of 30 elongated transverse processes with an overall prevalence of 2.21%. They were also more common in females (3.43%) than males (1.13%).

Arterial Complications of Thoracic Outlet Syndrome

Arterial complications of thoracic outlet compression have serious potential implications; however, these complications rarely appear. Between 1990 and 2006, prospectively collected data on 27 patients with arterial complications of thoracic outlet syndrome were analyzed. The causes of arterial compression were cervical rib (20 [74.1%]), abnormalities of the first thoracic rib (three [11.1%]), soft tissue anomalies (two [7.4%]), and hypertrophic callus after clavicle fracture (two [7.4%]). In all cases, a combined supraclavicular and infraclavicular approach was used. Decompression was achieved by cervical rib excision in 13 (48.1%) patients, combined cervical and first rib excision in seven (26%), and first rib excision in six (22.2%). Associated vascular procedures included resection and replacement of the subclavian artery (26 [97.3%]), one subclavian–axillary and one axillary–brachial bypass as well as 17 (63%) brachial embolectomies. The mean follow-up period was 7 years 4 months (range, 1-16 years). Two pleural entries, two transient brachial plexus injuries, and one subclavian artery rethrombosis were found. Complete resolution of symptoms with a return to full activity was noted in all cases. In surgical treatment, a combined anterior supraclavicular and infraclavicular approach is recommended as well as transbrachial embolectomy in all cases with symptoms of distal embolization.

Exercise-induced scalenus syndrome

BACKGROUND

Thoracic outlet syndrome is described as a group of distinct disorders producing signs and symptoms attributed to compression of nerves and blood vessels in the thoracic outlet region.

PURPOSE

To describe the exercise-induced scalenus anticus syndrome attributed to the anterior scalenus hypertrophy as a thoracic outlet syndrome underlying mechanism and to give recommendations for a safe and effective surgical treatment.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twelve young professional athletes admitted for thoracic outlet syndrome (8 cases of neurologic thoracic outlet syndrome, 4 cases of mixed neurologic and vascular thoracic outlet syndrome) who reported numbness, tingling, early fatigue, muscle weakness, and pain were enrolled in the study. Scalenus hypertrophy was suspected to be the causative factor. Scalenectomy was performed in all cases.

RESULTS

All patients had moderate to severe hypertrophy of the anterior scalenus muscle. Scalenectomy was performed, and there were no intraoperative or postoperative complications. Full activity was quickly achieved, and no recurrence of symptoms was documented.

CONCLUSION

Surgical intervention for scalenus anticus syndrome can allow an athlete to return to full activity and improve quality of life. Surgical intervention seems to be the treatment of choice in terms of restoring quality of life and physical activity.

An evidence-based review of magnetic resonance angiography for diagnosing arterial thoracic outlet syndrome

Arterial thoracic outlet syndrome (TOS) can be difficult to diagnose clinically. Recently, Magnetic Resonance Angiography (MRA) has been used to assist in the diagnosis of arterial TOS. The purpose of this article is to survey the current literature to establish the evidence for or against the use of MRA in the diagnosis of arterial TOS. The evidence-based search was conducted using PubMed, PEDro, Hooked on Evidence, EBM Journals, Ovid, Cochrane, and E medicine. The studies were graded as to the strength of recommendation and to the actual level of evidence. Statistics were calculated when sufficient data were present. The search yielded a total of seven studies. The studies received grades of recommendation that ranged from B to D. The current evidence in support of MRA as a valid test for diagnosing arterial TOS is weak and studies are not based on strong design.

Anatomy of nerve entrapment sites in the upper quarter

The purpose of this article is to review the anatomical features of the most common nerve entrapment sites of the brachial plexus and major peripheral nerves of the upper limb. In this account, the term "entrapment" is considered to be caused by compression, tension, or friction, or any combination of these factors. The anatomy, including important relationships of the brachial plexus, is reviewed and the points of potential entrapment of the plexus are described. Entrapment of the suprascapular and long thoracic nerves is also included. Particular attention is paid to the five major peripheral nerves that result from the brachial plexus and supply the peripheral aspect of the upper limb, i.e., the median, ulnar, musculocutaneous, radial, and axillary nerves. In each case, the nerve's course is described and the anatomical details of the entrapment points described. Where possible, the sites of entrapment are illustrated in cadaveric photographs.

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.

Etiology and pathology

Until the 1920s, TOS was believed to be a vascular condition caused by compression of the subclavian artery by a congenital anomaly, either a cervical rib or tight anterior scalen muscle. Today it is regarded primarily as a neurologic condition caused by neck trauma injuring and scarring the scalene muscles.

Endovascular management of venous thrombotic diseases of the upper torso and extremities

Central venous thrombosis in the upper torso can be either primary, occurring as a result of longstanding extrinsic compression, or secondary, resulting from an acquired intrinsic occlusive disease or foreign body. As in lower extremity deep vein thrombosis (DVT), anticoagulation therapy is the mainstay of therapy in upper torso and upper extremity DVT. However, in the presence of severely symptomatic acute thrombosis, pharmacologic and/or mechanical thrombolytic therapy represent the main invasive form of therapy for these conditions. After clearance of the acute thrombotic component, definitive management in patients with underlying anatomic abnormalities can be undertaken. Primary subclavian axillary vein thrombosis caused by extrinsic obstruction at the thoracic outlet is treated with thrombolytic therapy and anticoagulation followed by surgical decompression, whereas secondary causes of central venous obstruction and thrombosis are usually amenable to endovascular treatment with balloon angioplasty and stent placement. Postoperative interval anticoagulation is usually recommended. In addition to clinical follow-up, imaging follow-up with duplex sonography or conventional venography is usually recommended to assess the presence of restenosis and/or residual compression.

Experience of supraclavicular exploration and decompression for treatment of thoracic outlet syndrome

The purpose of this study was to assess the symptomatic outcome of patients with thoracic outlet syndrome who underwent decompression of the thoracic outlet. In our unit we prefer the supraclavicular approach, performing anterior scalenectomy with excision of fibrous bands or cervical ribs if present. Operative details were gained by theater logbook and case note review. Over a 6-year period, 31 patients (37 limbs) underwent thoracic outlet decompression. Of the 37 affected limbs, the indications for surgery were a combination of both neurological and vascular symptoms in 24 patients (65%), neurological symptoms in 24 (65%), and 4 patients (11%) had vascular symptoms alone. All patients were assessed for postoperative outcome either at out-patient clinics or by personal contact. From the results of this study we concluded that supraclavicular scalenectomy and cervical rib excision with selective first rib excision is a safe and effective procedure for most patients with thoracic outlet syndrome.