Developmental anomalies at the thoracic outlet: An analysis of 200 consecutive cases

First Rib Resection Using Videothoracoscopy in Patients With Vascular Thoracic Outlet Syndrome

Objective

Thoracic outlet syndrome (TOS) comprises a series of signs and symptoms produced by compression of neurovascular structures in any of the anatomical spaces of the thoracic outlet. First rib resection is a therapeutic alternative to decompress the structures of the thoracic outlet at the costoclavicular space. Traditional surgical approaches include transaxillary, supraclavicular, and infraclavicular access. The objective was to describe the surgical experience and follow up results of first rib resection using video assisted thoracoscopic surgery (VATS) in patients with vascular TOS.

Methods

Observational descriptive study based on a retrospective single centre analysis of a prospective database. Patients diagnosed with vascular TOS who underwent VATS first rib resection from January 2017 to December 2023 were included. The diagnosis for each subtype was based on the criteria defined in the standards of the American Society for Vascular Surgery in TOS. Among other things, the response to initial anticoagulation, peri-operative data, complications, symptom improvement, duration of post-operative anticoagulation, and symptom recurrence were investigated.

Results

Twenty nine patients diagnosed with vascular TOS who underwent VATS first rib resection, three of whom had bilateral procedures, were included. The total number of costal rib resections performed was 32 (31 venous TOS and one arterial TOS). The mean age was 29.1 ± 10.4 years and mean hospital stay was 2.7 ± 1.2 days. There were neither conversions to open surgery nor intra-operative complications, but there were two major post-operative complications (6.25%). No recurrences were detected during midterm follow up (median of 17.9 months, interquartile range 7.3, 45).

Conclusion

VATS first rib resection is a safe and feasible procedure. Unlike traditional approaches, this procedure allows physicians to make the resection under complete vision of the anatomical structures of the thoracic outlet reducing intra-operative complications and, if necessary, entire rib resection can be performed.

Predisposing Anatomy for Thoracic Outlet Syndrome and Functional Outcomes after Supraclavicular Thoracic Outlet Decompression in Athletes

Purpose

This study aims to examine predisposing anatomic factors and subsequent post-decompression functional outcomes among high-intensity athletes with thoracic outlet syndrome (TOS).

Materials and Methods

A single-institution retrospective review was performed on a prospective database of patients with TOS from 2018 to 2023 who had undergone operative decompression for TOS. Demographics, TOS characteristics, predisposing anatomy, operative details, and postoperative outcomes were examined. The primary outcome was postoperative return to sport. Secondary outcomes included vascular patency.

Results

A total of 13 patients who were engaged in high-demand athletic activity at the time of their diagnosis were included. Diagnoses included 8 (62%) patients with venous TOS, 4 (31%) patients with neurogenic TOS, and 1 (8%) patient with arterial TOS. Mixed vascular and neurogenic TOS was observed in 3 (23%) patients. The mean age of the cohort was 30 years. Abnormal scalene structure was observed in 12 (92%) patients, and abnormal bone structures were noted in 4 (27%) patients; 2 (15%) with cervical ribs and 3 (23%) patients with clavicular abnormalities. Prior ipsilateral upper extremity trauma was reported in 4 (27%) patients. Significant joint hypermobility was observed in 8 (62%) patients with a median Beighton score of 6. Supraclavicular cervical and/or first rib resection with scalenectomy was performed in all patients. One case of postoperative pneumothorax was treated non-operatively. Ten (77%) patients returned to sport. Duplex ultrasonography showed subclavian vein patency in all 8 patients with venous TOS and wide patency with no drop in perfusion indices in the patient with arterial TOS.

Conclusion

Athletes with TOS who required operative intervention had a high incidence of musculoskeletal aberrations and joint hypermobility. Supraclavicular decompression was associated with a high success rate, with overall good functional outcomes and good likelihood of patients returning to preoperative high-intensity athletics.

Current concepts in clinical features and diagnosis of thoracic outlet syndrome

The diagnosis and clinical features of thoracic outlet syndrome have long confounded clinicians, owing to heterogeneity in symptom presentation and many overlapping competing diagnoses that are "more common." Despite the advent and prevalence of high-resolution imaging, along with the increasing awareness of the syndrome itself, misdiagnoses and untimely diagnoses can result in significant patient morbidity. The authors aimed to summarize the current concepts in the clinical features and diagnosis of thoracic outlet syndrome.

Congenital, Acquired, and Trauma-Related Risk Factors for Thoracic Outlet Syndrome-Review of the Literature

Thoracic outlet syndrome is a group of disorders that affect the upper extremity and neck, resulting in compression of the neurovascular bundle that exits the thoracic outlet. Depending on the type of compressed structure, the arterial, venous, and neurogenic forms of TOS are distinguished. In some populations, e.g., in certain groups of athletes, some sources report incidence rates as high as about 80 cases per 1000 people, while in the general population, it is equal to 2-4 per 1000. Although the pathogenesis of this condition appears relatively simple, there are a very large number of overlapping risk factors that drive such a high incidence in certain risk groups. Undoubtedly, a thorough knowledge of them and their etiology is essential to estimate the risk of TOS or make a quick and accurate diagnosis.

General Overview and Diagnostic (Imaging) Techniques for Neurogenic Thoracic Outlet Syndrome

Thoracic outlet syndrome is an uncommon and controversial syndrome. Three different diagnoses can be made based on the compressed structure, arterial TOS, venous TOS, and neurogenic TOS, though combinations do exist as well. Diagnosing NTOS is difficult since no specific objective diagnostic modalities exist. This has resulted in a lot of controversy in recent decades. NTOS remains a clinical diagnosis and is mostly diagnosed based on the exclusion of an extensive list of differential diagnoses. To guide the diagnosis and treatment of TOS, a group of experts published the reporting standards for TOS in 2016. However, a consensus was not reached regarding a blueprint for a daily care pathway in this document. Therefore, we constructed a care pathway based on the reporting standards for both the diagnosis and treatment of NTOS patients. This care pathway includes a multidisciplinary approach in which different diagnostic tests and additional imaging techniques are combined to diagnose NTOS or guide patients in their treatment for differential diagnoses. The aim of the present work is to discuss and explain the diagnostic part of this care pathway.

Prevalence and anatomy of the anomalous subclavius posticus muscle and its clinical implications with emphasis in neurogenic thoracic outlet syndrome: Scoping review and meta-analysis

BACKGROUND

The subclavius muscle runs underneath the clavicle. However, there have been a few reports of a duplicated subclavius muscle which is commonly referred to as subclavius posticus muscle due to its orientation being posterior to the proper subclavius muscle. Its occurrence seems to potentially create a narrowing interval at the superior thoracic aperture as it crosses over the brachial plexus. It might also have functional influence on the shoulder girdle.

PURPOSE

To provide comprehensive gross anatomy description of the variant "subclavius posticus muscle" and to investigate its reported clinical implications with emphasis on its involvement in causing brachial plexus compression.

BASIC PROCEDURES

A scoping review with meta-analysis of the gross anatomy of the subclavius posticus muscle was conducted along with investigating its correlation to the thoracic outlet syndrome. Forty-seven articles were pooled through two rounds of the selection process. The relevant information was extracted and meta-analyzed.

MAIN FINDINGS

The scoping review and meta-analysis of the 47 articles revealed a total prevalence of 11/2069 (4.9%); 10/1369 (5.1%) in cadaveric studies, and 1/700 (5.0%) in MRI studies. The subclavius posticus muscle is a short triangular muscle with an average length of 12 cm and an average width of 1 cm. It originates from the sternal end of the first rib in most cases with reported variants of one case originating from the costoclavicular ligament and one case where it was fused with the proper subclavius muscle. Its insertion is more variable: on the superior border of the scapula with variable length in 71.35%, on the coracoid process of the scapula in 25.42%, and on the clavicle in 0.90%. The subclavian nerve seems to be the dominant nerve supply with a 57.6% prevalence, while 25.8% are innervated by the suprascapular nerve. Other reported nerves were the nerve to the myolohyoid (4.5%), accessory phrenic nerve (4.5%), and a direct branch from the brachial plexus (2.0%). The blood supply was reported (only once) to be from the suprascapular artery. However, the venous drainage was not established at all.

PRINCIPAL CONCLUSIONS

The subclavius posticus muscle is a variant muscle occurring with a reported overall prevalence of 4.9%. It can compress the brachial plexus as it runs across at the space of the superior thoracic aperture with exquisite contact, and this can lead to a neurogenic thoracic outlet syndrome. It also can be involved in the vascular thoracic outlet syndrome. Lastly, it is important not to omit its potential influence in shoulder joint instability to some extent.

Current Concepts in the Management of Neurogenic Thoracic Outlet Syndrome: A Review

Thoracic outlet syndrome is a constellation of signs and symptoms due to compression of the neurovascular bundle of the upper limb. In particular, neurogenic thoracic outlet syndrome can present with a wide constellation of clinical manifestations ranging from pain to paresthesia of the upper extremity, resulting in a challenge to correctly diagnose this syndrome. Treatment options range from nonoperative treatment, such as rehabilitation and physical therapy, to surgical correction, such as decompression of the neurovascular bundle.

Methods

Following a systematic review of the literature, we describe the need for a thorough patient history, physical examination, and radiologic images which have been reported to correctly diagnose neurogenic thoracic outlet syndrome. Additionally, we review the various surgical techniques recommended to treat this syndrome.

Results

Postoperative functional outcomes have been shown to be more favorable in arterial and venous thoracic outlet syndrome (TOS) patients when compared with neurogenic TOS patients, likely due to the ability to completely remove the site of compression in cases of vascular TOS as compared with incomplete decompression in neurogenic TOS.

Conclusions

In this review article, we provide an overview of the anatomy, etiology, diagnostic modalities, and current treatment options of correcting neurogenic TOS. Additionally, we offer a detailed step-by-step technique of the supraclavicular approach to the brachial plexus, a preferred approach for decompressing neurogenic TOS.

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.

Boney abnormalities cause arterial, venous, and/or neurogenic thoracic outlet syndrome

Background

Thoracic outlet syndrome (TOS) is a rare condition caused by compression of the neurovascular structures within the thoracic outlet. Different classifications of TOS exist depending on the neurovascular structure being compressed: neurogenic, venous, or arterial. Any of these forms can present independently or coexist with one other. TOS symptoms are sometimes precipitated by the presence of boney abnormalities that often require surgical intervention for ultimate resolution. This retrospective review will examine the presentations and outcomes of patients with TOS whose cause was a boney abnormality.

Methods

A total of 73 patients who underwent thoracic outlet surgery between 2016 and 2021 were retrospectively reviewed via electronic medical records. Twelve (16%) patients demonstrated boney abnormalities on presentation causing their symptoms. The patients with boney abnormalities were analyzed based on venous, arterial, or neurogenic TOS diagnosis.

Results

Of the 12 patients with boney abnormalities, 5 were classified as venous TOS, 6 patients as neurogenic TOS, and 1 as arterial TOS. The boney abnormalities were as follows: venous TOS: three clavicular fractures, one nonfused congenital clavicle, and one residual rib; neurogenic TOS: three fractured first ribs, one fractured clavicle, and two cervical ribs; and arterial TOS: fused first and second rib with bilateral cervical ribs and arterial compression. Postoperatively, there were no artery, vein, or nerve injuries. Five patients had a pneumothorax treated over night with a chest tube, and one patient had a superficial wound infection. The median hospital stay was 1 day. All patients completed physical therapy after surgery. All patients have symptom resolution at follow-up.

Conclusions

Patients with boney abnormalities constitute about one-fifth of patients who can present with all three forms of TOS: neurogenic, arterial, and venous, and some will have more than one of these presentations. Results in patients undergoing surgery with boney abnormalities causing thoracic outlet syndrome are excellent with symptom resolution and without substantial complications.

Breaking the constraint on the number of cervical vertebrae in mammals: On homeotic transformations in lorises and pottos

Mammals almost always have seven cervical vertebrae. The strong evolutionary constraint on changes in this number has been broken in sloths and manatees. We have proposed that the extremely low activity and metabolic rates of these species relax the stabilizing selection against changes in the cervical count. Our hypothesis is that strong stabilizing selection in other mammals is largely indirect and due to associated pleiotropic effects, including juvenile cancers. Additional direct selection can occur due to biomechanical problems (thoracic outlet syndrome). Low metabolic and activity rates are thought to diminish these direct and indirect effects. To test this hypothesis within the primates, we have compared the number of cervical vertebrae of three lorisid species with particularly low activity and metabolic rates with those of more active primate species, including with their phylogenetically closest active relatives, the galagids (bushbabies). In support of our hypothesis, we found that 37.6% of the lorisid specimens had an abnormal cervical count, which is a higher percentage than in the other nine primate families, in which the incidence varied from zero to 2.2%. We conclude that our data support the importance of internal selection in constraining evolvability and of a relaxed stabilizing selection for increasing evolvability. Additionally, we discuss that there is no support for a role of the muscularized diaphragm in the evolutionary constraint.

Thoracic outlet syndrome: a review

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

Imaging to intervention: Thoracic outlet syndrome

Thoracic outlet syndrome (TOS) is a clinical disorder resulting from compression of the neurovascular bundle of the lower neck and upper chest. TOS can be categorized into neurogenic, venous, and arterial subtypes which result from anatomical compression of the brachial plexus, subclavian vein, and subclavian artery, respectively. This can lead to neurogenic pain as well as vascular injury with thrombosis and thromboembolism. Interventional and diagnostic radiologists play a critical role in the imaging diagnosis and treatment of vascular TOS. Prompt imaging and endovascular management with surgical collaboration has been shown to provide the most successful and long-lasting clinical outcomes, from vessel patency to symptom relief. In this article, we review the anatomy and clinical presentations of TOS as well as the initial imaging modalities used for diagnosis. Furthermore, we detail the role of the diagnostic and interventional radiologist in the management of TOS, including pre-procedure and endovascular interventions, along with medical and surgical treatments. PRECIS: Diagnostic and Interventional Radiologists play a key role in diagnosis and management of vascular thoracic outlet syndromes and are critical for timely and successful outcomes.

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

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

Unique Case of Neurogenic Thoracic Outlet Syndrome with Arterial Compression in Patient with Bilateral Cervical Ribs and Osteochondroma of the Ribs

Background: Neurogenic thoracic outlet syndrome typically presents with paresthesia, pain, and impaired strength in the neck, shoulder, and arm, and is typically a diagnosis of exclusion. This condition is caused by compression of the brachial plexus, typically by a bony or soft tissue anomaly present congenitally and influenced by repetitive motion or significant trauma. Treatment typically involves removal of the first rib and anterior scalene to decompress the thoracic outlet and relieve stress to the brachial plexus if the patient has failed conservative treatment with physical therapy and lifestyle modifications. Case Presentation: We present a case of neurogenic thoracic outlet syndrome with arterial compression treated surgically via a transaxillary first rib and cervical rib resection in a patient with bilateral cervical ribs and osteochondromas of the ribs.

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.

A Single Institution 30-Year Review of Abnormal First Rib Resection For Thoracic Outlet Syndrome

OBJECTIVES

Congenital abnormalities of the first rib (ABNFR) are a rare cause of thoracic outlet syndrome (TOS). The range of abnormalities have not been clearly documented in the literature. Surgical decompression in these patients presents with increased complexity secondary to anomalous anatomy. Our goal is to review an institutional experience of first rib resection (FRR) performed for ABNFRs, to present a novel classification system, and to analyze outcomes according to clinical presentation.

METHODS

A prospectively collected database was used to identify individuals with ABNFRs who underwent FRR for TOS between 1990-2021. These individuals were identified both by preoperative imaging and intraoperative descriptions of the first rib after resection. Demographic, clinical, perioperative and pathological data were reviewed. ABNFRs were classified into three categories according to anatomical criteria: (I) Hypoplastic, (II) Fused, and (III) Hyperplastic. Outcomes were rated using the standardized Quick Disability of Arm Shoulder and Hand Scores (QDS), Somatic Pain Scores (SPS) and Derkash Scores (DkS).

RESULTS

Among the 2200 cases of TOS, there were 19 patients (0.8%) with ABNFR who underwent FRR. Average age at surgery was 30.5 (range 11-74), including 13 men and 6 women. Presentations included 9 arterial (ATOS), 6 neurogenic (NTOS), and 4 venous (VTOS) cases. There were 6 class I, 6 class II, and 7 class III ABNFRs. Among 6 NTOS patients there were 4 abnormal nerve conduction tests and 5 positive anterior scalene muscle blocks. Among the 9 patients with ATOS, thrombolysis was attempted in 5 patients, and of these, 3 ultimately required surgical thrombectomy. Of 4 VTOS cases, 2 were managed with thrombolysis, and 2 with anticoagulation alone. The approach for FRR was transaxillary in all patients. Secondary procedures included 1 pectoralis minor tenotomy, 1 scalenectomy, and 1 contralateral rib resection. No major neurological or vascular complications occurred. There was 1 patient who required surgical evacuation of a hematoma. Intraoperative chest tube placement was required in 5 patients secondary to pleural entry during dissection. There was an overall improvement in symptoms over an average follow-up of 7.4 months. QDS reduced from 49.7 pre-op to 22.1 (p<.05). SPS improved from 3.4 pre-op to 1.8. DkS scores were good to excellent in 79% of patients. Residual symptoms were noted in 7, and ATOS accounted for 5 (70%) of these. All patients were able to return to work.

CONCLUSIONS

Despite increased complexity, ABNFRs may be safely resected via transaxillary approach with low incidence of complications, very good symptom relief, and excellent outcomes. Congenital ABNFRs may by classified into three categories (hypoplastic, fused, and hyperplastic) with a variety of presentations, including ATOS, NTOS, and VTOS. Classification of ABNFRs allows concise description of abnormal anatomy which facilitates comparison between series and provides direction for surgical management to ultimately optimize patient outcomes.

Familial predisposition of thoracic outlet syndrome: does a familial syndrome exist? Report of cases and review of literature

INTRODUCTION

Neurogenic thoracic outlet syndrome (NTOS) is caused by compression of the brachial plexus. The clinical presentation of NTOS is characterized by symptoms of pain, paresthesia, numbness or muscle weakness in the neck, arm or hand.

METHODS

In this case report, five patients were diagnosed with NTOS. They all had a first degree relative with NTOS as well.

CONLUSIONS

These cases show familial predisposition in thoracic outlet syndrome. Could a form of familial TOS exist?

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.

C7 vertebra homeotic transformation in domestic dogs - are Pug dogs breaking mammalian evolutionary constraints?

The number of cervical vertebrae in mammals is almost constant at seven, regardless of their neck length, implying that there is selection against variation in this number. Homebox (Hox) genes are involved in this evolutionary mammalian conservation, and homeotic transformation of cervical into thoracic vertebrae (cervical ribs) is a common phenotypic abnormality when Hox gene expression is altered. This relatively benign phenotypic change can be associated with fatal traits in humans. Mutations in genes upstream of Hox, inbreeding and stressors during organogenesis can also cause cervical ribs. The aim of this study was to describe the prevalence of cervical ribs in a large group of domestic dogs of different breeds, and explore a possible relation with other congenital vertebral malformations (CVMs) in the breed with the highest prevalence of cervical ribs. By phenotyping we hoped to give clues as to the underlying genetic causes. Twenty computed tomography studies from at least two breeds belonging to each of the nine groups recognized by the Federation Cynologique Internationale, including all the brachycephalic 'screw-tailed' breeds that are known to be overrepresented for CVMs, were reviewed. The Pug dog was more affected by cervical ribs than any other breed (46%; P < 0.001), and was selected for further analysis. No association was found between the presence of cervical ribs and vertebral body formation defect, bifid spinous process, caudal articular process hypoplasia/aplasia and an abnormal sacrum, which may infer they have a different aetiopathogenesis. However, Pug dogs with cervical ribs were more likely to have a transitional thoraco-lumbar vertebra (P = 0.041) and a pre-sacral vertebral count of 26 (P < 0.001). Higher C7/T1 dorsal spinous processes ratios were associated with the presence of cervical ribs (P < 0.001), supporting this is a true homeotic transformation. Relaxation of the stabilizing selection has likely occurred, and the Pug dog appears to be a good naturally occurring model to further investigate the aetiology of cervical ribs, other congenital vertebral anomalies and numerical alterations.

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.

Late presentation of critical upper limb ischemia caused by pseudarthrosis of the clavicle

Compression of the subclavian artery in the thoracic outlet is a well-known phenomenon. In rare cases, bone abnormalities, such as pseudarthrosis of the clavicle, can cause arterial compression at this level. Pseudarthrosis may develop as a result of trauma, which is the more common form, or it may be congenital. Here, the authors describe the case of a 44-year-old patient with critical ischemia of the right upper limb. She had a history of untreated right clavicle fracture at 9 months of age which had progressed to pseudarthrosis and extrinsic compression of the subclavian artery causing occlusion. The segment of the clavicle involved was resected and late thromboembolectomy of the subclavian, brachial, distal arteries was performed, with good results.

Outcomes following operative management of thoracic outlet syndrome in the pediatric patients

Objectives

Thoracic outlet syndrome, a condition commonly reported in adults, occurs infrequently in the pediatric population. The objective of this study was to assess the outcome of surgical interventions of thoracic outlet syndrome in pediatric patients.

Methods

Clinical records of all pediatric patients with thoracic outlet syndrome who underwent operative repair from 2002 to 2015 in a tertiary pediatric hospital were reviewed. Pertinent clinical variables and treatment outcomes were analyzed.

Results

Sixty-eight patients underwent a total of 72 thoracic outlet syndrome operations (mean age 15.7 years). Venous, neurogenic, and arterial thoracic outlet syndromes occurred in 39 (57%), 21 (31%), and 8 (12%) patients, respectively. Common risk factors for children with venous thoracic outlet syndrome included sports-related injuries (40%) and hypercoagulable disorders (33%). Thirty-five patients (90%) with venous thoracic outlet syndrome underwent catheter-based interventions followed by surgical decompression. All patients underwent first rib resection with scalenectomy via either a supraclavicular approach (n = 60, 88%) or combined supraclavicular and infraclavicular incisions (n = 8, 12%). Concomitant temporary arteriovenous fistula creation was performed in 14 patients (36%). Three patients with arterial thoracic outlet syndrome underwent first rib resection with concomitant subclavian artery aneurysm repair. The mean follow-up duration was 38.4 ± 11.6 months. Long-term symptomatic relief was achieved in 94% of patients.

Conclusions

Venous thoracic outlet syndrome is the most common form of thoracic outlet syndrome in children, followed by neurogenic and arterial thoracic outlet syndromes. Competitive sports-related injuries remain the most common risk factor for venous and neurogenic thoracic outlet syndromes. Temporary arteriovenous fistula creation was useful in venous thoracic outlet syndrome patients in selective children. Surgical decompression provides durable treatment success in children with all subtypes of thoracic outlet syndrome.

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.

An unusual case of neurogenic thoracic outlet syndrome

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Lymphatic cyst is an unusual cause of neurogenic thoracic outlet syndrome.

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Only one previous case has been reported till date from the United States.

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Surgery is preferred to sclerotherapy, with higher success rates.

•

Combined supraclavicular and transaxillary approach provides excellent exposure.

Introduction

Neurogenic thoracic outlet syndrome (nTOS) is the most common manifestation of thoracic outlet syndrome (TOS), accounting for more than 95% of cases. It is usually caused by cervical ribs, anomalies in the scalene muscle anatomy or post-traumatic inflammatory changes causing compression of the brachial plexus.

Case presentation

: We present an unusual case of nTOS caused by a cystic lymphangioma at the thoracic outlet, with only one case reported previously in the literature. We used a combined supraclavicular and transaxillary approach for complete removal, which resulted in excellent recovery of the patient.

Discussion

Though lymphatic cysts may be commonly encountered in surgical practice, compression causing nTOS is extremely rare. The location of the lymphatic cyst with compression of the brachial plexus may provide a challenge for treatment. Surgical excision is the preferred method of management, with higher success rates than sclerotherapy.

Conclusion

Surgical excision to ensure complete removal of the cyst is recommended. Sclerotherapy may be used in cases where complete excision of the cyst wall may not be possible.

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.

The Epidemiological, Morphological, and Clinical Aspects of the Cervical Ribs in Humans

A familiarity with the anatomy of some types of bone anomalies is necessary for clinicians involved in many medical areas. The aim of this paper is to review the newest literature concerning the morphology, embryology, clinical image, and therapeutic methods of the cervical ribs in the humans. The incidence of cervical ribs has been found to vary from 0.58% in Malaysian population to 6.2% in Turkish population. Cervical ribs have clinical implications that are generally divided into neurological or vascular. This study is of particular importance for clinicians, as early identification of cervical ribs may prevent life-threatening complications.

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.

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.

Neurogenic thoracic outlet syndrome treatment by the supraclavicular approach

BACKGROUND

Thoracic outlet syndrome refers to compression of one or more of the neurovascular structures traversing the superior aperture of the thoracic cavity.

OBJECTIVE

A symptom-based patient-directed questionnaire was used to evaluate the outcome of the supraclavicular approach for treatment of neurogenic thoracic outlet syndrome.

PATIENTS AND METHODS

A prospective study was performed between April 2007 and October 2010. During this period, 97 patients in different age groups, with signs and symptoms of thoracic outlet syndrome, were surgically treated by the supraclavicular approach. The patients were aged between 14 and 60 years (mean 32.5 years), and the majority were female (89.69%). Surgery was performed on the left side in 52 patients and on the right side in 48, including 3 who had bilateral operations. The median follow-up was 11.2 months.

RESULTS

In 78% of the 100 operations, excellent improvement in symptoms was noted, there was partial improvement in 18%, and 4% resulted in no response.

CONCLUSIONS

First rib resection remains an important and essential step in the management of the thoracic outlet syndrome, in the absence of bony abnormalities. The supraclavicular approach can be employed with minimal morbidity and an excellent outcome.

High-definition video-assisted transaxillary first rib resection for thoracic outlet syndrome

Transaxillary first rib resection is a well-established effective surgical treatment for patients with symptomatic thoracic outlet syndrome, but surgical access may be limited and visualization is constrained. The use of high-definition video-assisted imaging overcomes these limitations. The use of high-definition video-assisted visualization of the anatomy enhances the surgeon's tactile feedback of the rib from the small open wound and is effective in providing better surgical access and allows clear identification of vital structures for the operating surgical team. This technique enhances the appreciation of anatomic detail, situational awareness of the team, and allows for more efficient assistance to the surgeon. Improved visualization also facilitates effective education of nurses, residents, and students.

The thoracic outlet syndromes

The term thoracic outlet syndrome (TOS) refers to a heterogeneous group of disorders, all of which have in common compression of one or more neurovascular elements at some point within the thoracic outlet. Of the five disorders comprising this group, four have all of the features expected of a syndrome-a recognized constellation of clinical features; an anatomic derangement accounting for these features; and a method of testing that identifies the anatomic derangement. Consequently, their recognition and management are relatively straightforward. Conversely, one of these five disorders (nonspecific TOS) lacks these correlations, which has generated considerable debate in the literature and caused some experts to doubt its existence altogether. The primary focus in this study is on the neurologic forms of TOS. However, for completeness and a better understanding of these neurologic manifestations, the vascular forms are also reviewed.

Post-traumatic thoracic outlet syndrome

BACKGROUND

To evaluate the clinical presentation, diagnostic and therapeutic management and outcome of 27 cases of post-traumatic thoracic outlet syndrome (PT TOS).

METHODS

Retrospective chart analysis.

RESULTS

Nineteen women and eight men were included in this study. Involvement in a traffic accident was the most common scenario. Fracture of either the first rib or the clavicle was reported in eight patients at the time of injury; in others, the diagnosis was cervical or shoulder soft tissue trauma. Upon presentation at our clinic at a mean 41 months after injury, four patients had bilateral symptoms and 17 reported decreased function of either the arm or hand. Two patients presented with severe lower trunk deficits including one who had received surgical intervention at both the cervical spine and elbow before diagnosis of TOS was made. Sixteen and 15 patients were suffering from some degree of anxiety and/or depression. Upon diagnosis of neurogenic TOS, the two patients with atrophy of the hand musculature were treated surgically. Conservative treatment was applied to all other patients. Six months after presentation to our clinic, nine patients demonstrated a significant improvement. The remainder that reported incapacitating symptoms were offered surgical treatment. Three patients declined the latter. Fifteen patients received surgical treatment via an anterior supraclavicular approach with resection of the anterior scalene muscles. Eleven patients had resection of the middle scalene muscle while five had resection of an osseous structure (partial claviculectomy, C7 transverse process or a cervical rib). The two patients with atrophy of the hand only slightly improved their motor deficit but had a notable relief of symptoms of pain. Postoperative improvement occurred in 80% of surgically treated patients.

CONCLUSIONS

The majority of patients suffering from a post-traumatic TOS present a neurogenic, usually subjective syndrome. Prompt therapeutic management is necessary, addressing both physical and psychological complaints. Most patients are cured or well improved by conservative and/or surgical treatment.

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.

Analysis of cervical ribs in a series of human fetuses

In humans, an increasing body of evidence has linked the frequency of cervical ribs to stillbirths, other malformations and early childhood cancers. However, the frequency of cervical ribs in a putatively healthy fetal population is not sufficiently known to assess the actual medical risks of these prenatal findings. We therefore analyzed the presence of skeletal anomalies in a series of 199 electively aborted fetuses, which were whole-mount stained with alizarin red specific for skeletal tissues. Results show that approximately 40% of the fetuses had cervical ribs, even though external congenital abnormalities such as craniofacial and limb defects were absent. A literature overview indicates that the observed frequency of cervical ribs is comparable to results previously obtained for deceased fetuses with no or minor congenital anomalies, and higher than expected for healthy fetuses. This unexpected result can probably in part be explained by a higher detection rate of small cervical ribs when using alizarin red staining instead of radiographs. Additionally, studies in the literature suggest that the size of a cervical rib may indicate the severity of abnormalities, but this possibility requires further research. Anomalies of the axial skeleton are known to be caused by a disturbance of early development, which alters Hox gene expression, but in this study the origin of the stress could not be verified as maternal medical data were not available. The co-occurrence of rudimentary or absent 12th ribs in 23.6% of the cases with cervical ribs indicates that in approximately 8% of the fetuses a homeotic shift occurred over a larger part of the vertebral column. This suggests that the expression of multiple Hox genes may have been affected in these fetuses. Together, the high incidence of cervical ribs and also their co-occurrence with rudimentary or absent 12th ribs suggests that there may have been a disturbance of early development such that the studied fetuses are probably not informative about the general population. Future studies determining the frequency of cervical ribs in a more healthy fetal population are therefore needed to evaluate their potential as an indicator of medical risks.

Transgenic over-expression of growth differentiation factor 11 propeptide in skeleton results in transformation of the seventh cervical vertebra into a thoracic vertebra

Growth differentiation factor 11 (GDF11) is one of the significant genes that control skeletal formation. Knockout of GDF11 function causes abnormal patterning of the anterior/posterior axial skeleton. The mRNA of GDF11 is initially translated to a precursor protein that undergoes a proteolytic cleavage to generate the C-terminal peptide or mature GDF11, and the N-terminal peptide named GDF11 propeptide. The propeptide can antagonize GDF11 activity in vitro. To investigate the effects of GDF11 propeptide on GDF11 function in vivo, we generated transgenic mice that over-express the propeptide cDNA in skeletal tissue. The transgenic mice showed formation of extra ribs on the seventh cervical vertebra (C7) as a result of transformation of the C7 vertebra into a thoracic vertebra. The GDF11 propeptide transgene mRNA was detected in tail tissue in embryos and was highly expressed in tail and calvaria bones after birth. A high frequency of C7 rib formation was noticed in the transgenic mouse line with a high level of transgene expression. The anterior boundaries of Hoxa-4 and Hoxa-5 mRNA in situ expressions showed cranial shifts from their normal prevertebra locations in transgenic embryos. These results demonstrated significant effects of GDF11 propeptide transgene on vertebral formation, which are likely occurring through depressing GDF11 function and altered locations of Hoxa-4 and Hoxa-5 expression.

Thoracic outlet syndrome part 1: clinical manifestations, differentiation and treatment pathways

Thoracic outlet syndrome (TOS) is a challenging condition to diagnose correctly and manage appropriately. This is the result of a number of factors including the multifaceted contribution to the syndrome, the limitations of current clinical diagnostic tests, the insufficient recognition of the sub-types of TOS and the dearth of research into the optimal treatment approach. This masterclass identifies the subtypes of TOS, highlights the possible factors that contribute to the condition and outlines the clinical examination required to diagnose the presence of TOS.

Thoracic outlet syndrome in children and young adults

OBJECTIVES

Thoracic outlet syndrome has been well described in the population between 25 and 40 years of age, and is less frequently reported in those in the first two decades of life. The objective of this study was to review results with onset of TOS in the first two decades of life to determine type of presentation and outcomes from surgical intervention.

METHODS AND MATERIALS

Charts of all patients in the first two decades of life, operated on for TOS between 1994 and 2006 were reviewed with follow-up by clinic visit and phone survey to assess the patients' current level of activity and relief from symptoms.

RESULTS

Twelve patients were identified (13 operations), with a mean age of 16.8 years. Acute ischemic symptoms were the initial presentation for 38%, venous TOS in 24%, and neurogenic symptoms in 38%. All patients had symptom relief with surgery with a mean time to resolution of 10.9 weeks. All patients remained symptom free or improved at follow-up.

CONCLUSIONS

Vascular TOS is much more common in TOS presenting in the first two decades of life. Surgical intervention for TOS in this population results in long-lasting symptom relief and should be considered for all subtypes of patients.

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%).