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

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

Histologic evidence of brachial plexus compression sites at the thoracic inlet and variations in formation of the lower trunk in cadavers.

BACKGROUND: In thoracic "outlet" syndrome (TOS), pathologic evidence is well documented for vascular but not neurologic compression. We hypothesized that histologic evidence of compression would be identified at sites where the upper trunk was impacted by the anterior scalene muscle and the lower trunk by anatomic anomalies or the first rib. The purpose of this study was to investigate this hypothesis in human cadavers. MATERIALS AND METHODS: Twenty-five cadavers' brachial plexuses were dissected and excised. Histologic and descriptive analysis was directed at juncture 1, the upper trunk and anterior scalene muscle, and juncture 2, C8 and T1 nerve roots (lower trunk) with the posterior border of the first rib. Measurements were obtained at the juncture of the T1 nerve root with the C8 nerve root in relationship to the first rib. RESULTS: Histologic analysis demonstrated epineurial and perineurial fibrosis, myelin thinning, and Renaut bodies at junctures 1 and 2. Lower trunk formation occurred on or lateral to the first rib in 66% of specimens, with asymmetry in 32% of cadavers. A muscle of Albinus was present in 18% of cadavers. A large dorsal scapular artery coursed through 36% of plexuses with a high, arched subclavian artery. CONCLUSIONS: We report histologic changes consistent with chronic compression of the upper and lower plexus in the thoracic inlet at hypothesized sites of brachial plexus compression that may correlate with clinical neck/shoulder (upper trunk) and "ulnar nervelike" (C8-T1/lower trunk) symptoms. Anatomic anomalies identified should alert the surgeon to variations of lower trunk formation at compression sites.

Imaging of non-specific complaints of the arm, neck, and/or shoulder (CANS): role of the scalene muscles and piercing variants in neurogenic thoracic outlet syndrome.

Complaints of the arm, neck and/or shoulder (CANS) are common in the general population (40%) and workers (30%) and have significant economic impact. Twenty-three conditions have been designated as specific CANS. Cases where no cause is identified are reported as non-specific CANS; these cases make up the majority of CANS. Non-specific CANS presentations overlap with clinical entities including cervicobrachial and scalene myofascial syndromes that are associated with neurogenic thoracic outlet syndrome (NTOS). The scalene muscles have been identified as the commonest site of NTOS, although this has been reported to be functional and in conjunction with cervicothoracic junction variants that compromise the brachial plexus lower trunk. Anatomical variants in relation to both the scalene muscles and brachial plexus are not widely recognised in the clinical and imaging literature; however, pass-through and pass-over (or "piercing") variants of the brachial plexus upper trunk and scalene muscles have been well described in the anatomical and anaesthetic literature. In this review, we demonstrate the presence and describe the imaging of scalene muscle pathology and variant muscle-brachial plexus anatomy affecting the upper trunk that are underdiagnosed causes of non-specific CANS presentations and NTOS.

Anatomy and Embryology of the Thoracic Outlet.

The thoracic outlet is the space between the thorax and axilla through which the subclavian vein, subclavian artery, and brachial plexus travel from their central origins to their peripheral termini. Its bounds include the clavicle, first thoracic rib, insertion of the pectoralis minor muscle onto the coracoid process of the humerus, and the sternum. It contains three areas: the scalene triangle, the costoclavicular space, and the subcoracoid or pectoralis minor space. Aberrant anatomy is common in the thoracic outlet and may predispose patients to compression of the neurovascular bundle and development of clinical thoracic outlet syndrome (TOS). Much of this aberrancy is explained by the embryologic origins of the structures that comprise the thoracic outlet. A thorough understanding of this anatomy and embryology is therefore critical to the understanding of TOS.

Overview of venous pathology related to repetitive vascular trauma in athletes.

BACKGROUND: Athletes are generally young, high-functioning individuals. Pathology in this cohort is associated with a decrease in function and consequently has major implications on quality of life. Venous disorders can be attributed to a combination of vascular compression with a high burden of activity. OBJECTIVE: This article promotes increased awareness of these uncommon conditions specific to the athlete by summarizing pathophysiology, clinical features, investigation, and treatment protocols for use in clinical practice. Prognostic outcomes of these management regimens are also discussed, allowing for clinicians to counsel these high-functioning individuals appropriately. With the aim of providing an overview of sport-related venous pathology, a literature review was undertaken identifying articles that were independently reviewed by the authors. RESULTS: Lower limb venous thrombosis has been identified in young, high-functioning athletes attributed to both compression-related venous trauma, associated with repetitive movements resulting in intimal damage, and blunt trauma. The diagnosis and treatment follow the same protocols as for the general population. Of note, early ambulation is advocated, with an aim to return to premorbid (noncontact) function within 6 weeks. Athletes performing high-intensity repetitive upper limb movement, such as baseball players, are predisposed to upper limb deep venous thrombosis (DVT). Diagnosis follows the same protocols as for lower extremity DVT; however, the optimal treatment strategy remains debated. Current guidelines advocate the use of anticoagulation alone. A specific subset of primary upper limb DVT is effort thrombosis, where there is compression at the level of the thoracic outlet. Thrombolysis with first rib resection is indicated in the acute setting within 14 days. In cases of complete occlusion, surgical decompression with venous reconstruction may be required. Popliteal vein entrapment syndrome is also discussed. This entity has been identified as an overuse injury associated with popliteal vein compression. Duplex ultrasound examination is indicated as a first-line investigation, with conservative noninvasive options considered as an initial management strategy. Chronic venous insufficiency or persistent symptoms may require subsequent surgical decompression. CONCLUSIONS: Key conditions including upper extremity and lower extremity venous thrombosis, venous aneurysms, Paget-Schroetter syndrome (effort thrombosis), and popliteal vein entrapment syndrome are discussed. Further studies evaluating long-term outcomes on morbidity for current treatment regimens in upper extremity DVT, effort thrombosis, venous thoracic outlet syndrome, and popliteal venous entrapment syndrome are required.

Troisier sign and Virchow node: the anatomy and pathology of pulmonary adenocarcinoma metastasis to a supraclavicular lymph node

ABSTRACT: Metastatic spread of cancer via the thoracic duct may lead to an enlargement of the left supraclavicular node, known as the Virchow node (VN), leading to an appreciable mass that can be recognized clinically ­ a Troisier sign. The VN is of profound clinical importance; however, there have been few studies of its regional anatomical relationships. Our report presents a case of a Troisier sign/VN discovered during cadaveric dissection in an individual whose cause of death was, reportedly, chronic obstructive pulmonary disease. The VN was found to arise from an antecedent pulmonary adenocarcinoma. Our report includes a regional study of the anatomy as well as relevant gross pathology and histopathology. Our anatomical findings suggest that the VN may contribute to vascular thoracic outlet syndrome as well as the brachial plexopathy of neurogenic thoracic outlet syndrome. Further, the VN has the potential to cause compression of the phrenic nerve, contributing to unilateral phrenic neuropathy and subsequent dyspnea. Recognition of the Troisier sign/VN is of great clinical importance. Similarly, an appreciation of the anatomy surrounding the VN, and the potential for the enlarged node to encroach on neurovascular structures, is also important in the study of a patient. The presence of a Troisier sign/VN should be assessed when thoracic outlet syndrome and phrenic neuropathy are suspected. Conversely, when a VN is identified, the possibility of concomitant or subsequent thoracic outlet syndrome and phrenic neuropathy should be considered.

The thoracic outlet syndromes: Part 1. Overview of the thoracic outlet syndromes and review of true neurogenic thoracic outlet syndrome.

The thoracic outlet syndromes (TOSs) are a group of etiologically and clinically distinct disorders with 1 feature in common: compression of 1 or more neurovascular elements as they traverse the thoracic outlet. The medical literature reflects 5 TOSs: arterial; venous; traumatic neurovascular; true neurogenic; and disputed. Of these, the first 4 demonstrate all of the features expected of a syndrome, whereas disputed TOS does not, causing many experts to doubt its existence altogether. Thus, some categorize disputed TOS as a cervicoscapular pain syndrome rather than as a type of TOS. To better understand these disorders, their distinctions, and the reasoning underlying the categorical change of disputed TOS from a form of TOS to a cervicoscapular pain syndrome, a thorough understanding of the pertinent anatomy, pathology, pathophysiology, and the electrodiagnostic manifestations of their pathophysiologies is required. This review of the TOSs is provided in 2 parts. In this first part we address information pertinent to all 5 TOSs and reviews true neurogenic TOS. In part 2 we review the other 4 TOSs. Muscle Nerve 55: 782-793, 2017.

Anatomical variations in the brachial plexus roots: implications for diagnosis of neurogenic thoracic outlet syndrome.

Neurogenic thoracic outlet syndrome (NTOS) is the most common type of TOS. Typically it results from impingement of the neurovasculature as it passes between the anterior and middle scalene muscles; this classic anatomical relationship being the foundation of clinical diagnosis. Positional testing relies on vascular compromise occurring when the subclavian artery is compressed in this space. This study describes several anatomical variations observed in this relationship. Sixty-five cadavers (35m/30f) were assessed to determine the frequency and extent of brachial plexus branching variants. A total of thirty-one variations from "classic" anatomy were observed (47.7%). In two specimens (3.1%), the entire superior trunk coursed completely anterior to the anterior scalene in a position of relative vulnerability. In 27 instances, a portion of or the entire superior trunk pierced the anterior scalene muscle, and in two, the middle trunk also pierced the muscle belly. Interestingly, while two bilateral branching variations were observed, the majority occurred unilaterally, and almost exclusively on the left side. There were no sex differences in frequency. The high frequency of these variations and their potential to predispose patients to neurogenic TOS suggest that current diagnostic methods may be insufficient in clinical diagnosis. Due to lack of vascular compromise, patients with the piercing variant would not display positive signs on the traditional positional tests. The use of ultrasound to determine the route of the brachial plexus could determine whether this variation is present in patients who suffer from TOS symptoms but lack a diagnosis based on traditional positional testing.

Neurogenic thoracic outlet syndrome: Are anatomical anomalies significant?

BACKGROUND: Thoracic outlet syndrome (TOS) is one of the most poorly understood syndromes. Neurogenic TOS is found in 95% of cases. The described anatomical spaces transform and evolve into 'entrapment spaces'. The aetiology is unclear. This study was based on the observation by a single surgeon that there appeared to be a high incidence of anatomical abnormalities in patients with neurogenic TOS. OBJECTIVE: To attempt to clearly define anatomical anomalies causing TOS. METHODS: The records from a prospectively maintained computer database of 219 patients submitted for surgery over a 10-year period (1999-2009) were reviewed. A substudy was done on the patients operated on over the last 4 years (n=63) in whom details of the intraoperative anatomical findings were meticulously recorded. RESULTS: Over the last 4 years, the surgical findings in the last 63 patients (67 operations) revealed a significant number of anatomical abnormalities believed to be responsible for the nerve compression. Brachial plexus anomalies were found in 99% of the patients--the majority comprised the postfixed configuration. In addition, 58% had a soft-tissue anomaly, 27% had a bony anomaly and 3% had other abnormalities. The majority had combinations of these abnormal findings. CONCLUSION: These findings strongly suggest that there is usually an identifiable anatomical cause, typically the brachial plexus, for the symptoms of TOS. We strongly recommend that the supraclavicular approach be used in order to define anatomical aberrations. Brachial plexus configuration anomalies causing TOS have not been emphasised previously. Further detailed recordings of these findings may help us better understand the aetiology of this poorly defined syndrome.

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.

[A case of true neurogenic thoracic outlet syndrome accompanied by an aberrant right subclavian artery].

A 65-year-old woman experienced progressive intrinsic muscle wasting on the right hand over a period of 7 years. The distribution of muscular atrophy and weakness was consistent with the area innervated by the right C8 and Th1 nerve roots. Neurophysiological examination suggested a right lower trunk lesion. An elongated right transverse process of the C7 vertebra and an aberrant subclavian artery were detected on computed tomography images, and the right lower trunk of the brachial plexus appeared to be lifted upward on magnetic resonance images. The patient was diagnosed with true neurogenic thoracic outlet syndrome. A fibrous band extending from the elongated transverse process was found during surgery, and symptoms did not progress further after resection of the band. True neurogenic thoracic outlet syndrome can cause monomelic amyotrophy, and localized neuroimaging and detailed neurophysiological examination were useful for diagnosis.

A video-assisted thoracoscopic approach to transaxillary first rib resection.

OBJECTIVE: Thoracic outlet syndrome (TOS) can be associated with neurologic, arterial, or venous deficiencies. When nonsurgical treatment has failed to adequately palliate TOS, surgical intervention is indicated. The supraclavicular and transaxillary approaches are currently the most commonly used approaches for first rib resection, yet little has been reported to date on outcomes of minimally invasive procedures, such as video-assisted thoracoscopic surgery (VATS). The purpose of this article was to describe a minimally invasive approach to TOS and the associated outcomes. METHODS: This study is a retrospective analysis of a prospectively maintained database. Patients who failed nonsurgical therapy for TOS were referred to our practice for evaluation of surgery with a VATS minimally invasive first rib resection. Between 2001 and 2010, 66 VATS procedures were performed on 58 patients (41 women, 17 men). Patients were followed postoperatively for a mean time of 13.5 months. RESULTS: Forty-one patients were women (70.7%), and the mean age was 40.5 years, with a patient age range of 17 to 59 years. The mean length of hospital stay was 2.47 days; median length of stay was 2 days. There were a total of eight complications (12.1%). There were no mortalities. CONCLUSIONS: Video-assisted thoracoscopic surgery first rib resection for TOS is another feasible option for TOS, which can be added to the armamentarium of the thoracic surgeon. The outcomes associated with our technique are comparable with the outcomes related to other current standards of care.

Atypical thoracic outlet syndrome and reverse flow thromboembolism.

BACKGROUND: Thoracic outlet syndrome is rare in children but may have serious consequences. Compression of the neurovascular structures at the thoracic outlet by anomalous soft tissues or cervical ribs may cause neurological deficits in the upper limb and venous or arterial insufficiency. PATIENTS: The symptoms and signs of this condition are well documented, but we describe two patients with an atypical presentation. We review similar published cases where delay in diagnosis resulted in cerebrovascular catastrophe. Our patients presented with relatively nonspecific central nervous system symptoms and were found to have thoracic outlet compression. Both were treated by surgical decompression of the thoracic outlet, and the symptoms completely resolved with no long-lasting neurological consequences. CONCLUSIONS: We highlight the importance of these rare cases because of the risk of stroke and discuss the theory behind the pathological process.

Comparison of blood pool and extracellular gadolinium chelate for functional MR evaluation of vascular thoracic outlet syndrome.

OBJECTIVE: To compare performance of single-injection blood pool agent (gadofosveset trisodium, BPA) against dual-injection extracellular contrast (gadopentetate dimeglumine, ECA) for MRA/MRV in assessment of suspected vascular TOS. MATERIALS AND METHODS: Thirty-one patients referred for vascular TOS evaluation were assessed with BPA (n=18) or ECA (n=13) MRA/MRV in arm abduction and adduction. Images were retrospectively assessed for: image quality (1=non-diagnostic, 5=excellent), vessel contrast (1=same signal as muscle, 4=much brighter than muscle) and vascular pathology by two independent readers, with a separate experienced reader providing reference assessment of vascular pathology. RESULTS: Median image quality was diagnostic or better (score ≥ 3) for ECA and BPA at all time points, with BPA image quality superior at abduction late (BPA 4.5, ECA 4, p=0.042) and ECA image quality superior at adduction-early (BPA 4.5; ECA 4.0, p=0.018). High qualitative vessel contrast (mean score ≥ 3) was observed at all time points with both BPA and ECA, with superior BPA vessel contrast at abduction-late (BPA 3.97 ± 0.12; ECA 3.73 ± 0.26, p=0.007) and ECA at adduction-early (BPA 3.42 ± 0.52; ECA 3.96 ± 0.14, p<0.001). Readers readily identified arterial and venous pathology with BPA, similar to ECA examinations. CONCLUSION: Single-injection BPA MRA/MRV for TOS evaluation demonstrated diagnostic image quality and high vessel contrast, similar to dual-injection ECA imaging, enabling identification of fixed and functional arterial and venous pathology.

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.

Thoracic outlet syndrome in 3T MR neurography-fibrous bands causing discernible lesions of the lower brachial plexus.

OBJECTIVES: To investigate whether targeted magnetic resonance neurography (MRN) of the brachial plexus can visualise fibrous bands compressing the brachial plexus and directly detect injury in plexus nerve fascicles. METHODS: High-resolution MRN was employed in 30 patients with clinical suspicion of either true neurogenic thoracic outlet syndrome (TOS) or non-specific TOS. The protocol for the brachial plexus included a SPACE (3D turbo spin echo with variable flip angle) STIR (short tau inversion recovery), a sagittal-oblique T2-weighted (T2W) SPAIR (spectral adiabatic inversion recovery) and a 3D PDW (proton density weighted) SPACE. Images were evaluated for anatomical anomalies compressing the brachial plexus and for abnormal T2W signal within plexus elements. Patients with abnormal MR imaging findings underwent surgical exploration. RESULTS: Seven out of 30 patients were identified with unambiguous morphological correlates of TOS. These were verified by surgical exploration. Correlates included fibrous bands (n = 5) and pseudarthrosis or synostosis of ribs (n = 2). Increased T2W signal was detected within compressed plexus portion (C8 spinal nerve, inferior trunk, or medial cord) and confirmed the diagnosis. CONCLUSIONS: The clinical suspicion of TOS can be diagnostically confirmed by MRN. Entrapment of plexus structures by subtle anatomical anomalies such as fibrous bands can be visualised and relevant compression can be confirmed by increased T2W signal of compromised plexus elements. KEY POINTS: • MR neurography (MRN) can aid the diagnosis of thoracic outlet syndrome (TOS). • Identifiable causes of TOS in MRN include fibrous bands and bony anomalies. • Increased T2W signal within brachial plexus elements indicate relevant nerve compression. • High positive predictive value allows confident and targeted indication for surgery.

Imaging of the non-traumatic brachial plexus.

The first line imaging of the non-traumatic brachial plexus is by MRI. Knowledge of the anatomy and commonest variants is essential. Three Tesla imaging offers the possibility of 3D isotropic sequences with excellent spatial and contrast enhancement resolutions, which leads to time saving and quality boosting. The most commonly seen conditions are benign tumor lesions and radiation damage. Gadolinium is required to assess inflammatory or tumour plexopathy. MRI data should be correlated with FDG-PET if tumor recurrence is suspected.