Diagnosis of thoracic outlet syndrome

Hand Strength Deficit in Patients with Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome (NTOS) is a chronic painful and disabling condition. Patients complain about upper-limb paresthesia or weakness. Weakness has been considered one of the diagnostic criteria of NTOS, but objective comparisons to healthy controls are lacking. We compared the grip and the key pinch strengths between NTOS patients and healthy controls. Grip strength was evaluated with a hydraulic hand dynamometer and the key pinch with a pinch gauge. All the patients with NTOS completed a QuickDASH. We included prospectively 85 patients with NTOS, 73% female and 27% male. The mean age was 40.4 ± 9.6. They were compared to 85 healthy subjects, 77.6% female and 22.4% male. Concerning the grip, symptomatic hands of NTOS patients had significantly 30% less strength compared to control hands (p ≤ 0.001), and 19% less strength compared to asymptomatic hands (p = 0.03). Concerning the key pinch, symptomatic hands of patients with NTOS had significantly 19.5% less strength compared to control hands (p ≤ 0.001). Grip and key pinch strengths had a significant correlation with the QuickDASH (r = −0.515 and r = −0.403, respectively; p ≤ 0.001). Patients with NTOS presented an objective hand strength deficit compared to healthy controls. This deficit was significantly correlated to the upper-limb disability. These findings confirm the interest of hand strength evaluation in the diagnostic process of patients with NTOS.

Differences in Passive Shoulder Range of Motion Between Baseball Players With Neurogenic Thoracic Outlet Syndrome and Matched Healthy Controls

Background:

Neurogenic thoracic outlet syndrome (nTOS) is becoming more recognized as a diagnosis in the throwing athlete. Currently, there is limited information on the clinical presentation and development of nTOS in baseball players.

Purpose:

To compare passive shoulder range of motion (ROM) and anatomic humeral retrotorsion (HRT) of baseball players diagnosed with nTOS with a group of healthy, matched controls.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 53 adolescent baseball players diagnosed with nTOS (age, 17.2 ± 2.3 years; height, 180.9 ± 10.1 cm; weight, 80.0 ± 13.3 kg) were compared with 53 healthy baseball players (age, 17.2 ± 2.4 years; height, 183.9 ± 9.0 cm; weight, 83.8 ± 11.5 kg). Participants were measured for shoulder internal rotation (IR) and external rotation (ER) ROM and HRT. All measurements were taken bilaterally, and the differences (throwing to nonthrowing arm) were used to calculate mean values for glenohumeral internal rotation difference, glenohumeral external rotation difference (GERD), total rotational motion difference (TRM_diff), and anatomic humeral retrotorsion difference. Group comparisons were made between the nTOS and control players using multivariate analysis of variance, and descriptive comparisons were made with independent t tests.

Results:

There were no significant differences between groups in age, height, weight, or years of experience. Players in the nTOS group had significantly less throwing arm ER compared with controls (103.4° ± 10.4° vs 109.6° ± 7.5°, respectively; P = .001) and GERD (3.0° ± 9.2° vs 8.8° ± 9.2°, respectively; P = .002). TRM_diff was significantly greater in nTOS (–11.1° ± 11.1°) than in controls (–3.7° ± 9.4°) (P < .001).

Conclusion:

In the current study, adolescent baseball players diagnosed with nTOS were evaluated with shoulder ROM differences when compared with a matched healthy cohort. A loss of throwing arm ER appeared to be the main factor behind shoulder ROM changes in the nTOS group.

Lipomas as an Extremely Rare Cause for Brachial Plexus Compression: A Case Series and Systematic Review

Introduction  Brachial plexus lipomas are extremely rare benign tumors that may cause slow progression of neurological deficits leading to thoracic outlet syndrome. Up to now, surgery remains challenging. The aim of this study is to present our surgical treatment regime and long-term neurological outcome in three cases of giant brachial plexus lipomas and to show results of systematic review.

Patients and Methods  Retrospective analysis of our database “peripheral nerve lesion” to identify patients suffering from brachial plexus lipomas between January 1, 2012, and December 31, 2019. Systematic review was performed for literature published until March 31, 2020, analyzing PubMed, Google Scholar, Scopus, and the Cochrane Collaboration Library independently by two authors.

Results  Over the past years, three patients suffering from giant brachial plexus lipomas attended to our neurosurgical department. All patients underwent preoperative magnetic resonance imaging (MRI), ultrasound examinations, and electrophysiological testing. Tumors were removed microsurgically via anterior/posterior, supraclavicular/infraclavicular, and combined approaches. The patients were accessed postoperatively by MRI and clinical follow-up. Systematic review of the literature revealed 22 cases, which were analyzed in regard to demographics, surgical treatment, and neurological outcome.

Conclusion  Brachial plexus lipomas are an extremely rare cause for brachial plexus compression. Total microsurgical removal with intraoperative electrophysiological monitoring is the treatment of choice with excellent long-term MRI and clinical outcome.

Evaluation of Patients with Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome (NTOS) results from the compression or irritation of the brachial plexus within the thoracic outlet. The associated symptoms result in significant disability and negative effects on patient health-related quality of life. The diagnosis of NTOS, despite being the most common type of TOS, remains challenging for surgeons, in part due to the nonspecific symptoms and lack of definitive diagnostic testing. In this article, we present the essential components of the evaluation of patients with NTOS including a thorough history and physical examination, stress maneuvers, diagnostic and therapeutic imaging, and assessment of disability using standardized patient-centered instruments.

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.

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.

Imaging Assessment of Thoracic Outlet Syndrome

Imaging studies play a significant role in assessment of thoracic outlet syndrome. In this article, we discuss the etiology and definition of thoracic outlet syndrome and review the spectrum of imaging findings seen in patients with thoracic outlet syndrome. We then discuss an optimized technique for computed tomography and MRI of patients with thoracic outlet syndrome, based on the experience at our institution and present some representative examples. Based on our experience, a combination of computed tomography angiography and MRI (with postural maneuvers) effectively demonstrate thoracic outlet syndrome abnormalities.

How Common Is Thoracic Outlet Syndrome?

The incidence of neurogenic thoracic outlet syndrome is completely unknown, and has been wildly overestimated in the past. Based on a prospectively maintained database at our academic Thoracic Outlet Center, we estimate the yearly incidence of neurogenic and venous thoracic outlet syndrome to be approximately 3 and 1 per 100,000 population, respectively. The ratio of neurogenic to venous thoracic outlet syndrome seems to be approximately 80:20 based on presentation, and 75:25 based on operative correction. These data will help to understand the impact of these disorders, and perhaps help to guide resource management.

Reoperation for Persistent or Recurrent Neurogenic Thoracic Outlet Syndrome

Identifying the exact cause for persistent and recurrent neurogenic thoracic outlet syndrome (NTOS) is challenging even with high-resolution imaging of the thoracic outlet. Improvement can be achieved with redo first rib resection, although the posterior first rib remnant is one of several potential points of brachial plexus compression. In approaching reoperative surgery for NTOS, the aim is to provide complete thoracic outlet decompression as guided by the patient's history, physical examination, and adjunctive imaging. This may involve resection of the posterior first rib remnant, scar tissue encasing the brachial plexus, elongated C7 transverse process, cervical rib, and/or pectoralis minor tendon.

Late Venous Thoracic Outlet Syndrome After Anatomic Fixation of a Diaphyseal Clavicle Fracture: A Case Report

CASE

We report the case of a 29-year-old man with a displaced mid-diaphyseal clavicle fracture that healed in anatomic position without fracture callus after surgical treatment but developed symptoms of late venous thoracic outlet syndrome (TOS) 19 months postoperatively. He was diagnosed with proximal subclavian vein thrombosis and was treated with urgent thrombolysis and staged first rib resection with resolution of symptoms.

CONCLUSIONS

Late venous TOS is a potential complication of clavicle fracture, even in the setting of anatomic reduction and primary bone healing. This entity has previously only been described in the setting of nonunion and malunion.

Neurogenic Thoracic Outlet Syndrome with Supraclavicular Release: Long-Term Outcome without Rib Resection

Our aim was to define clinical long-term outcome of surgery for neurogenic thoracic outlet syndrome without rib resection, and to find factors predicting long-term results. For the 94 patients, the main outcomes were pain, numbness, weakness, and upper-extremity function. The Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) survey, the Cervical-Brachial Symptom Questionnaire (CBSQ), and a numerical rating system served as functional outcome measures. Mean follow-up was 12.9 years. Preoperative pain diminished from 7.8 to 2.2, numbness from 7.4 to 4.0, and weakness from 7.3 to 3.8. Grip strength increased from 25.7 to 31.8 kg. QuickDASH averaged at follow-up 37.1 and CBSQ 51.5. No correlation appeared between smoking and long-term results regarding pain, numbness, weakness, or functioning. Positive TOS provocative tests or intraoperative anatomical findings like consistency of the scaleni muscles showed no correlation with outcome. 82% of female and 57% of male patients reported that aid from this surgery had been excellent or good; 69% reported that surgery helped considerably for at least a mean 9.9 years. The risk for worse self-reported long-term outcome was higher among men, but neither BMI nor age at surgery associated with self-reported outcome. Pain, numbness, and weakness significantly decreased and function improved after supraclavicular release without rib resection. We found no significant preoperative nor per-operative factors predicting long-term results.

Quadrangular Space Syndrome: A Narrative Overview

OBJECTIVE

The purpose of this narrative review of the literature is to provide an overview of quadrangular space syndrome with special attention to its clinical presentation, differential diagnosis, and treatment.

METHODS

A narrative review of the English-language, peer-reviewed literature was performed using the key words "axillary nerve," "quadrangular space," "quadrilateral space," and "posterior humeral circumflex artery." Databases searched were Medline Complete, Cumulative Index to Nursing and Allied Health Literatures, and Index to Chiropractic Literature. The search period was from 1983 through January 2020.

RESULTS

There were 85 articles selected for this review. A summary and overview are provided.

CONCLUSION

Quadrangular space syndrome is an uncommon cause of shoulder pain. Clinicians should consider it as a diagnosis after ruling out more common shoulder conditions and examining other concurrent diseases.

Thoracic Outlet Syndrome: A Narrative Review

Thoracic outlet syndrome comprises a group of disorders that result in compression of the brachial plexus and subclavian vessels exiting the thoracic outlet. Symptoms include pain, paresthesia, pallor, and weakness depending upon the compromised structures. While consensus in diagnostic criteria has not yet been established, a thorough patient history, physical exam, and appropriate imaging studies are helpful in diagnosis. General first-line therapy for thoracic outlet syndrome is a conservative treatment, and may include physical therapy, lifestyle modifications, NSAIDs, and injection therapy of botulinum toxin A or steroids. Patients who have failed conservative therapy are considered for surgical decompression. This article aims to review the epidemiology, etiology, relevant anatomy, clinical presentations, diagnosis, and management of thoracic outlet syndrome.

FETOS: A Self-Questionnaire for Functional Evaluation in Thoracic Outlet Syndrome

OBJECTIVE

Thoracic outlet syndrome is caused by the compression of blood vessels and nerves leading to the upper limbs; the level of functional discomfort in activities of daily living can be significant. This discomfort has been evaluated using a variety of nonspecific scales, prompting the development a specific self-questionnaire ("Functional Evaluation in Thoracic Outlet Syndrome). Here, the scale's test-retest reliability, sensitivity to change, and criterion validity were assessed.

DESIGN

Between May 2015 and July 2017, a total of 37 patients were assessed during an intensive rehabilitation program. The Functional Evaluation in Thoracic Outlet Syndrome self-questionnaire comprises 16 items rated on a 4-point scale: impossible, major discomfort, moderate discomfort, or no difficulty. A total score is then calculated and the usual level of discomfort is rated on a numerical scale. The questionnaire was completed on day (D)1, D2, and the day of discharge.

RESULTS

The questionnaire showed very good test-retest reliability, with an overall correlation coefficient above 0.91. The overall score was highly sensitive to change, with a significant median improvement (-5.89) between D1 and discharge (P < 0.001). Of the 16 items, 9 showed significant scalability in their individual sensitivity to change. The criterion validity was moderate: the coefficient for the correlation with the numerical scale was 0.68 on D1 (P < 0.001), 0.55 on D2 (P < 0.001), and 0.69 at discharge (P < 0.001).

CONCLUSIONS

The Functional Evaluation in Thoracic Outlet Syndrome self-questionnaire is a quick, simple way of assessing the impact of thoracic outlet syndrome on activities of daily living. The overall score and most of the items displayed good reproducibility and sensitivity to change.

Contemporary Management of Arterial Thoracic Outlet Syndrome

BACKGROUND

Arterial thoracic outlet syndrome (aTOS) is characterized by compression of the subclavian artery as it exits the thoracic girdle. Chronic and repetitive compression leads to several degrees of arterial wall damage. The treatment is varied and depends on the presentation severity. This study aimed to describe the contemporary experience in managing arterial thoracic outlet syndrome at a large tertiary hospital.

METHODS

We conducted a single-institution retrospective review of aTOS cases from January 2009 to January 2020. Demographic data, clinical presentation, medical images, operative notes, and outcomes were assessed.

RESULTS

Thirteen aTOS cases were identified. The mean age was 43 ± 10 years, and 11 (85%) were women. Both sides were equally affected: right (7 cases, 54%) and left (6 cases, 46%). The most common clinical presentation was arm claudication (7 cases, 54%). Other presentations were: acute arm ischemia, pulsatile neck mass and distal embolization. Cervical ribs were identified by plain X-rays in most cases. All patients were submitted to surgical decompression through the supraclavicular approach. Patients with early disease stages were not submitted to arterial reconstruction and were followed with duplex scan. Arterial reconstruction was done in advanced disease stages (5 cases, 38%): end-to-end anastomosis, interposition graft, and bypass graft. The mean follow-up duration was 32,6 ± 25 months. In all patients, the subclavian artery/graft was patent, and the vascular symptoms were entirely resolved. There were no deaths or amputations.

CONCLUSIONS

Arterial thoracic outlet syndrome has a varied clinical presentation. Cervical ribs are the most common anatomic abnormalities. The diagnosis was based on history, physical examination, and imaging exams. Surgery consisted of supraclavicular decompression, arterial resection, and vascular reconstruction, according to the disease stage. The outcomes were excellent.

Subclavian Vessel Compression Assessed by Duplex Scanning in Patients with Neurogenic Thoracic Outlet Syndrome and No Vascular Signs

Neurogenic thoracic outlet syndrome (NTOS) is the most frequent form of TOS. It may affect both sides, but specific complementary exams are lacking. We aimed to evaluate duplex scanning results in a group of patients with unilateral or bilateral NTOS and no clinical vascular signs, referred for rehabilitation. We performed a retrospective observational study in patients with unilateral or bilateral NTOS and no vascular symptoms. Subclavian vessels were assessed by duplex scanning. Compressions were considered in case of >50% of increased or decreased blood flow. A total of 101 patients met NTOS criteria; mean age was 40 +/− 10.2; 79.2% women. Seventy patients had a unilateral NTOS and 31 a bilateral form. Duplex scanning showed that 56.4% of the patients had vessels compression, 55.7% in the unilateral group and 58.1% in the bilateral (p = 0.81). In unilateral NTOS, 21 (30%) patients had bilateral vascular compression, 17 (24.3%) had ipsilateral compression and 1 (1.4%) had contralateral compression. In bilateral NTOS, 15 (48.4%) had bilateral compression and 3 (9.7%) compression on only one side. We found a significant difference of the rate of vascular compressions between symptomatic and non-symptomatic upper-limbs, 54.5% vs. 32.9%, respectively, (p = 0.002) and a significant association between symptomatic upper-limbs and vascular compression (OR = 2.45 [95%IC: 1.33–4.49]; p = 0.002). The sensitivity and the specificity of the duplex scanning were 54.5% and 67%, respectively. The ROC curve area was of 0.608 [95%IC: 0.527–0.690]. Despite a highly significant association between symptomatic upper-limbs and vascular compression, duplex scanning did not help make the diagnosis of NTOS.

Evaluation of functions after surgical treatment in patients with arterial thoracic outlet syndrome using QuickDASH

Background

The aim of this study was to examine the validity and reliability of the Quick Disability of the Arm, Shoulder and Hand questionnaire in patients with arterial thoracic outlet syndrome.

Methods

A total of 106 patients (15 males, 91 females; mean age: 30.7±10.2 years; range, 13 to 60 years) with arterial thoracic outlet syndrome were included in this prospective study between January 2015 and December 2018. The questionnaire was administered to all patients before and six months after surgery. The patients were operated using a transaxillary or supraclavicular approach under general anesthesia.

Results

The Cronbach"s alpha value of the questionnaire was found to be 0.85 and the scale consisted of two factors. The change in both the functional status subscale scores (p<0.001) and the physical pain subscale scores (p<0.001) were statistically significantly different before and after surgery. At the end of six months, 53% of the patients with at least one mild difficulty continued to have complaints related to hand, arm and shoulder.

Conclusion

Based on our study results, this questionnaire is a valid and reliable tool for measuring and monitoring disease symptoms in patients with arterial thoracic outlet syndrome.

Surgical treatment of cervical rib-associated arterial thoracic outlet syndrome

Resumo A forma arterial da síndrome do desfiladeiro torácico é rara e está associada a uma anomalia anatômica, geralmente uma costela cervical. Suas manifestações são muito variadas. Este artigo tem como proposta relatar dois casos de apresentações clínicas distintas: microembolização e aneurisma. Em ambos, uma costela cervical estava presente. O diagnóstico foi realizado através da história, do exame físico, das manobras posturais e das radiografias. A angiotomografia computadorizada proporcionou o detalhe anatômico necessário para o planejamento operatório. O tratamento cirúrgico foi realizado pela abordagem supraclavicular, com sucesso em ambos casos.

An Interesting Case of a Cold Left Arm

Inter-arm variability in blood pressure readings typically signifies arterial disease between the aortic arch and the subclavian artery. The differential diagnosis includes thoracic aortic dissection, atherosclerosis, thoracic outlet syndrome, and subclavian artery stenosis and thrombosis. In patients with prior coronary artery bypass grafting, including the internal mammary artery, several of those conditions can compromise coronary blood flow and lead to myocardial ischemia. Here we discuss a case of left subclavian artery thrombosis, which compromised left internal mammary artery blood flow and led to ischemic ventricular tachycardia.

Beyond Giant Cell Arteritis and Takayasu's Arteritis: Secondary Large Vessel Vasculitis and Vasculitis Mimickers

PURPOSE OF REVIEW

To provide an overview of mimickers of large vessel vasculitis (LVV), by the main presenting manifestation, i.e., systemic, vascular, and cranial manifestations.

RECENT FINDINGS

The main differential diagnoses in patients with giant cell arteritis (GCA) and Takayasu arteritis (TAK) presenting with systemic manifestations (i.e., fever, anorexia, weight loss, night sweats, arthralgia/myalgia, and/or increased inflammatory indexes) are neoplastic, infectious, or other inflammatory conditions. In patients with vascular manifestations (such as peripheral ischemia, vascular stenoses, or aneurysms), atherosclerosis and non-inflammatory vascular diseases should be excluded. In those presenting with predominant cranial symptoms (i.e., temporal headache, jaw claudication, scalp tenderness, transient or permanent vision loss), other causes of headache, cerebrovascular accidents, optic neuropathy, and neuromuscular syndromes need to be considered. The diagnosis of LVV maybe challenging, especially when patients present with atypical or incomplete clinical forms. In these cases, a multidisciplinary approach is strongly recommended.

Supraclavicular Resection of a Cervical Rib Causing Thoracic Outlet Syndrome: 2-Dimensional Operative Video

Presence of a cervical rib results from overdevelopment of the seventh cervical vertebrae.1-3 The cervical rib along with scalene muscles can cause neurogenic thoracic outlet syndrome.4,5 Rib resection is typically done via anterior approach, using either supraclavicular or transaxillary route.6,7 We present an operative video detailing supraclavicular resection of a cervical rib causing neurogenic thoracic outlet syndrome with direct decompression of the lower trunk of the brachial plexus. The patient presented with severe symptoms including hand atrophy. We were able to directly visualize the rib and resect it, along with scalene musculature. We present 3-mo follow-up data noting clinical improvement in neuropathic symptoms.

An isolated double-crush-syndrome in posttraumatic thoracic outlet syndrome - A case report

•

Neurovascular compression.

•

Non-standardized treatment.

•

Clinical, apparative tests.

Thoracic outlet Syndrome (TOS) includes all disorders caused by compression of all neurovascular Structures in the upper thoracic outlet (Ross and Owners, 1966, Bürger and Arterien, 2014, Sanders and Annest, 2017).

The Double-Crush-Syndrome (DBS) defines multilevel lesions along a neurovascular trunk caused by mechanical compression in different areas.

Pectoralis-minor-syndrome (PMS) is also classified in the disorders of he upper thoracic outlet and was also known as hyperabductionsyndrome or subcoracoidal-syndrome.

Between 2015–2019 our department treatet 488 patients suffering from neurological, vascular or combined TOS. Surgical treatment, depending on clinical and specific diagnostics was performed in 175 cases via transaxillary approach, including cervical rib resection, first rib resection, neurolysis of plexus brachialis, thoracal sympathectomy or vascular reconstruction. In all this year just a single patient with double crush syndrome was present.

Case presentation and methods

We report a case of a 28-years old female patient, reported in line with the SCARE criteria [13], suffering from neurvascular compression in the upper thoracic outlet after surgically treated clavicula fracture.

She developed typical symptomes of a Thoracic Outlet Syndrome.

Conclusion

Double-Crush-Syndrome in patients with Thoracic Outlet Syndrome are very rare, case reports seldomly exist. The diagnosis requires a specific clinical testing and x-ray radiography. Furthermore dynamic tests like ultrasound and angiography and neurophysiological testing requires a high degree of experience, so the compressed area can be detected.

Treatment includes an attempt of best medical and physical therapy, in case of failure a surgical treatment is necessary.

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.

Respiratory Dysfunction in Individuals With Thoracic Outlet Syndrome

OBJECTIVE

The purpose of this study was to compare pulmonary function and respiratory muscle strength and endurance in individuals with thoracic outlet syndrome (TOS) and healthy participants.

METHODS

Sixty-two individuals with TOS (mean age 30.81 ± 10.69 years; 10 male, 52 female) and 47 healthy individuals (mean age 30.64 ± 9.16 years; 14 male, 33 female) participated in this study. Pulmonary function testing was performed using a spirometer. Respiratory muscle strength (maximal inspiratory pressure [MIP] and maximal expiratory pressure [MEP]) were measured using a mouth pressure device. Respiratory muscle endurance was tested at 35% MIP and measured as the time in seconds from the start of the test to voluntary exhaustion.

RESULTS

Age distribution and physical characteristics were similar between the groups (P > .05). All pulmonary function parameters except for peak expiratory flow rate were similar in patients with TOS and healthy controls (P > .05). Patients with TOS had significantly lower peak expiratory flow rate, MIP, MIP%, MEP, MEP%, and respiratory muscle endurance compared with controls (P < .05). Forty-six patients with TOS (74.2%) had MIP values below the lower limit of the 95% CI of the control group (97.05-113.88 cmH₂O), and 53 patients with TOS (85.2%) had MEP values below the lower limit of the 95% CI of the control group (124.74-146.49 cmH₂O).

CONCLUSION

Expiratory flow rate and respiratory muscle strength and endurance may be adversely affected in TOS. Trunk muscles perform both postural and breathing functions. Therefore, disruption in one function may negatively affect the other.

Effort Thrombosis Presenting as Unilateral "Pumped" Arm in a Climber

Upper extremity injuries are common among the growing population of climbers. Although conditions affecting musculoskeletal structures are the most common causes of symptoms, a comprehensive differential diagnosis is necessary to avoid the misdiagnosis of high-morbidity conditions in this patient population. We present a case of a climber with acute edema, erythema, and pain of the entire right upper extremity. After confirmation of an upper extremity deep vein thrombosis by ultrasound, and in the absence of secondary causes for his thrombotic process, he was diagnosed with effort thrombosis. The patient was treated acutely with anticoagulation, catheter thrombectomy, direct thrombolysis, and balloon angioplasty followed by surgical decompression of the subclavian vein. Owing to the importance of early diagnosis and initiation of treatment, it is critical to keep disorders affecting the upper thoracic vascular structures in consideration.

The Incidence of Thoracic Outlet Syndrome

BACKGROUND

Thoracic outlet syndrome (TOS) refers to a constellation of compressive problems that occur at the thoracic outlet. TOS has been recognized since the 19th century, and the "modern" era of treatment, especially for neurogenic TOS, dates from at least the 1970s. Despite this, however, the incidence and prevalence of these syndromes are almost completely unknown. To attempt to answer this fundamental question, we established a prospective database of all patients who presented to our clinic with a diagnosis of potential TOS, as described below.

METHODS

We established a database of all patients referred to our clinic from July 1, 2014 to May 2018. All subjective data, the tentative diagnosis, and plan at the time of the office visit were prospectively recorded. For patients with neurogenic TOS (NTOS), a standardized workup sheet was used based on the Society for Vascular Surgery's recently published reporting standards document. For patients with venous TOS (VTOS), diagnosis was made by clinical examination and ultrasound, and for those with arterial TOS (ATOS), by clinical examination, ultrasound, and cross-sectional imaging when needed.

RESULTS

From July 1, 2014, to May 1, 2018, 526 patients were referred to our institution with a diagnosis of possible TOS. Of these, 432 (82%) were referred with symptoms suggestive of NTOS, 84 (16%) with symptoms suggestive of VTOS, and 10 (2%) with findings and/or symptoms suggestive of ATOS. NTOS: After evaluation as per the algorithm previously mentioned, 234 patients (54%) were judged high suspicion for NTOS, 126 (30%) moderate suspicion, and 72 (17%) low suspicion; 360 (83%) of those originally referred were felt to potentially have NTOS. Of the 84 patients with VTOS, 25 (30%) presented with acute Paget-Schroetter syndrome, 41 (48%) with subacute or chronic occlusion, and 18 (21%) with McCleery's syndrome. Finally, 8 of the 10 limbs had true ATOS; of these, 6 (75%) underwent decompression and repair and 2 (25%) endovascular intervention only. Based on referral assumptions and population density in our area, the incidence of NTOS seems to be between 2 and 3 cases per 100,000 people per year and that of VTOS between 0.5 and 1 per 100,000 people per year, ATOS being sporadic. The ratio of those with decent suspicion for NTOS and VTOS, respectively, is about 80:20, whereas that of those undergoing surgical decompression is about 75:25.

CONCLUSIONS

The rates of NTOS and VTOS, as aforementioned, are approximately 25 and 8 per year in a metropolitan area of 1,000,000, respectively. Although a rare disease, these numbers are not insignificant, although are much lower than prior estimates.

Neuralgic amyotrophy: a paradigm shift in diagnosis and treatment

Neuralgic amyotrophy (NA), also known as Parsonage-Turner syndrome, is characterised by sudden pain attacks, followed by patchy muscle paresis in the upper extremity. Recent reports have shown that incidence is much higher than previously assumed and that the majority of patients never achieve full recovery. Traditionally, the diagnosis was mainly based on clinical observations and treatment options were confined to application of corticosteroids and symptomatic management, without proven positive effects on long-term outcomes. These views, however, have been challenged in the last years. Improved imaging methods in MRI and high-resolution ultrasound have led to the identification of structural peripheral nerve pathologies in NA, most notably hourglass-like constrictions. These pathognomonic findings have paved the way for more accurate diagnosis through high-resolution imaging. Furthermore, surgery has shown to improve clinical outcomes in such cases, indicating the viability of peripheral nerve surgery as a valuable treatment option in NA. In this review, we present an update on the current knowledge on this disease, including pathophysiology and clinical presentation, moving on to diagnostic and treatment paradigms with a focus on recent radiological findings and surgical reports. Finally, we present a surgical treatment algorithm to support clinical decision making, with the aim to encourage translation into day-to-day practice.

A Case Report on Paget-Schroetter Syndrome Presenting as Acute Localized Rhabdomyolysis

Introduction

The life- or limb-threatening differential diagnosis for upper extremity swelling can include deep vein thrombosis (DVT), infectious processes, and compartment syndrome. Chronic anatomic abnormalities such as axillary vein stenosis are rarely a consideration in the emergency department.

Case Report

We present a 26-year-old female with history of Chiari type 1 malformation who presented with acute left arm swelling. Initial workup, including point-of-care ultrasound, revealed the presence of significant soft tissue swelling without evidence of DVT.

Conclusion

Further workup revealed an early, localized rhabdomyolysis secondary to axillary vein stenosis or venous thoracic outlet syndrome, also known as Paget-Schroetter syndrome.

REACT - A novel flow-independent non-gated non-contrast MR angiography technique using magnetization-prepared 3D non-balanced dual-echo dixon method: Preliminary clinical experience

Flow-independent relaxation-based non-contrast MR angiography techniques yield good signal-to-noise ratio and high blood-tissue contrast, complementing non-contrast flow-dependent and contrast-enhanced MR angiography techniques in the assessment of vascular disorders. However, these techniques often suffer from imaging artifacts at high magnetic field strengths or across large fields-of-view. Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) is a recently introduced flow-independent non-gated non-contrast three-dimensional MR angiography technique that has been developed to mitigate some of these issues. We present our initial experience with the clinical applications of REACT in imaging disorders of the central and peripheral vascular systems.

Supraclavicular Versus Transaxillary First Rib Resection for Thoracic Outlet Syndrome

Background: Thoracic outlet syndrome (TOS) results from compression of neurovascular structures supplying the upper extremity as they exit the thoracic outlet. Depending on the clinical presentation, surgical decompression may be required. Objectives: Transaxillary (TA) and supraclavicular (SC) approaches are both widely utilized and deemed effective. Our objective was to review the outcomes for both approaches at our institution. Methods: A retrospective review was conducted on patients who underwent thoracic outlet decompression between 2010 and 2015. Data on demographics, comorbidities, presenting symptoms, and type of TOS (neurogenic, venous, or arterial) were collected. Operative times, length of hospital stay, perioperative complications, and outcomes were also studied. Results: A total of 82 thoracic outlet decompression procedures were performed during the study period: 42% neurogenic TOS, 46% venous TOS, and 12% arterial TOS. In total, 49% underwent TA approach and 51% underwent SC approach. Adjunct procedures were performed in 13% of patients. There were no significant differences in average operative time (151.3 ± 54.1 minutes versus 126.1 ± 36.1 minutes, P = .11) or hospital stay (2.3 ± 1.9 days versus 2.4 ± 1.4 days, P = .23) between both groups, respectively. Minor complications were seen in 6% of patients with no significant difference in both groups, whereas 6% had major complications. No perioperative or 30-day mortalities were observed. In total, 49% of patients had complete resolution of symptoms, 46% had partial improvement, and 5% had no improvement. There was no difference in symptom resolution between either group. Conclusions: TA and SC approaches are equally safe and effective for the treatment of TOS. SC decompression allows for adjunct procedures and vascular reconstructions.

Acute effects of manual therapy on respiratory parameters in thoracic outlet syndrome

Background

This study aims to investigate the acute effects of manual therapy on pain perception and respiratory parameters in patients with thoracic outlet syndrome.

Methods

The study included 10 patients with thoracic outlet syndrome (1 male, 9 females; mean age 31.3±9.0 years; range, 20 to 43 years). Patients were accepted in a single session of manual therapy involving the cervical spine and thorax. Stretching of scalene, upper trapezius, sternocleidomastoid, rectus abdominis, hip flexor muscles; and mobilization of first rib, cervical and thoracic spine, sacroiliac joints and thorax were applied as manual therapy program. Pain perceptions of upper arm and neck were assessed with visual analog scale. Measurements were performed before and immediately after of a 30-minute session of manual therapy. Pulmonary function testing was performed with a spirometer. Respiratory muscle strength (inspiratory and expiratory muscle strength, maximal inspiratory pressure and maximal expiratory pressure, respectively) was measured. Respiratory muscle endurance was recorded using sustained threshold loading of 35% maximal inspiratory pressure.

Results

There were no significant changes in any pulmonary function parameters or maximal expiratory pressure following manual therapy intervention (p>0.05). However, maximal inspiratory pressure and respiratory muscle endurance improved (p<0.05). Pain perceptions of upper arm and neck reduced after treatment (p<0.05).

Conclusion

A 30-minute single manual therapy session improved inspiratory muscle strength and respiratory muscle endurance but not pulmonary function and expiratory muscle strength in patients with thoracic outlet syndrome. Manual therapy may facilitate functional breathing and support use of primary respiratory muscles more effectively together with rapid pain reduction. The long-term effects of regular manual therapy on respiratory parameters should be investigated after surgical procedures.

Measurement of Outlet Pressures Favors Rib Resection for Decompression of Thoracic Outlet Syndrome

BACKGROUND

When conservative therapy for thoracic outlet syndrome fails, scalenectomy with or without first-rib resection (FRR) is the treatment of choice. We measured pressure in the costoclavicular space before and after FRR at time of neurogenic thoracic outlet syndrome release to evaluate whether FRR is required to completely decompress the costoclavicular space.

METHODS

Using a supraclavicular exposure for anterior-middle scalenectomy with FRR, costoclavicular space pressures were measured using a balloon catheter with the patient's arm in neutral anatomic position, secondarily, the arm abducted and externally rotated. Pressures were recorded in both arm positions before scalenectomy, after scalenectomy, and after FRR. Paired Student's t test was used to compare differences in group means for paired samples. Patient-reported outcomes were reported using the Derkash classification and quick disabilities of the arm, shoulder, and hand (qDASH) questionnaire.

RESULTS

Fifteen patients (16 cases) surgically treated for neurogenic thoracic outlet syndrome were included in this retrospective study. There was no significant difference in pressure change between arm positions before scalenectomy (161.56 ± 71.65 mm Hg difference) or after scalenectomy (148.5 ± 80.24 mm Hg difference). There was a significant difference in pressure change between post-scalenectomy and post-FRR arm positions; mean pressure change between arm positions after FRR was 50.56 ± 40.28 mm Hg. Mean postoperative qDASH score was 20 ± 23.2. All patients reported improvement in symptoms and functional status.

CONCLUSIONS

Supraclavicular first rib resection for management of neurogenic thoracic outlet syndrome can be safely performed with favorable outcomes. The pressure increase in the costoclavicular space caused by arm abduction and external rotation was significantly reduced only after FRR, raising concerns about potential incomplete costoclavicular space decompression with scalenectomy alone for neurogenic thoracic outlet syndrome management.

An overview of the findings of dynamic upper limbs’ arterial and venous duplex in cases of vascular thoracic outlet syndrome

Background

To describe the findings of the dynamic upper limb arterial and venous duplex in the assessment of vascular compression in cases of VTOS. This study was conducted on 58 patients with VTOS; they were evaluated by dynamic duplex examination.

Results

Vascular compression was subdivided into a venous compression that was detected in (84.4%,n = 49), arterial compression that was seen in (1.7%,n = 1), and combined arterial and venous compression that was present in (13.7%,n = 8); bilateral compression was existing in (94.4%,n = 55), compression at the scalene triangle was seen in (1.7%,n = 1), at the costo-clavicular space was seen in (91.3%,n = 53), and at the retro-pectoral space was depicted in (8.6%,n = 5).

Complicated arterial compression was detected in (1.7%,n = 1), whereas venous complications were seen in (6.8%,n = 4).

Conclusion

Dynamic duplex ultrasound offered a simple, noninvasive, and quick technique that can help in the evaluation of the vascular thoracic outlet syndrome without exposure to ionizing radiation or contrast media administration like that in CT; nevertheless, it is done with the patient in the upright position, thus avoiding the high false-negative results associated with the supine position that is used in the CT and MRI studies.

Early and Late Outcomes of Surgery for Neurogenic Thoracic Outlet Syndrome in Adolescents

BACKGROUND

Neurogenic thoracic outlet syndrome is a condition that is both complex to diagnose and manage successfully. The aim of our study was to present our experience and outcomes of surgical management of thoracic outlet syndrome in adolescents.

METHODS

We performed a retrospective analysis of a prospectively held database of consecutive adolescents (age 10-19 years) who underwent surgery for neurogenic thoracic outlet syndrome between 2005 and 2017 at our university hospital.

RESULTS

Fourteen patients were identified (19 operations), with a mean age of 16.5 years (SD: 1.9). All patients had symptomatic relief with surgery with low complication rates (1 pneumothorax). Median hospital stay was 2 days (IQR: 1). There were no early recurrences but 5 late ones which occurred 2, 2.5, 3, 4 and 10 years after surgery (20%). None required a second procedure and were managed successfully with physiotherapy.

CONCLUSIONS

Surgical intervention for thoracic outlet syndrome in the adolescent population results in excellent outcomes in the short term. However, we found that recurrence of symptoms in this population is common and patients need to be counseled clearly about this prior to surgical intervention. However in our experience these do not require further surgery.

Morbidity of First Rib Resection in the Surgical Repair of Thoracic Outlet Syndrome

Background: Thoracic outlet syndrome (TOS) is a complex entity resulting in neurogenic or vascular manifestations. A wide array of procedures has evolved, each with its own benefits and drawbacks. The authors hypothesized that treatment of TOS with first rib resection (FRR) may lead to increased complication rates. Methods: A retrospective case control study was performed on the basis of the National Surgical Quality Improvement Program database from 2005 to 2014. All cases involving the operative treatment of TOS were extracted. Primary outcomes included surgical and medical complications. Analyses were primarily stratified by FRR and secondarily by other procedure types. Results: A total of 1853 patients met inclusion criteria. The most common procedures were FRR (64.0%), anterior scalenectomy with cervical rib resection (32.9%), brachial plexus decompression (27.2%), and anterior scalenectomy without cervical rib resection (AS, 8.9%). Factors associated with increased medical complications included American Society of Anesthesiologists (ASA) classification of 3 or greater and increased operative time. The presence or absence of FRR did not influence complication rates. Conclusions: FRR is not associated with an increased risk of medical or surgical complications. Medical complications are associated with increased ASA scores and longer operative time.

Transposition of external jugular to proximal internal jugular vein for relief of venous thoracic outlet syndrome and maintenance of arteriovenous fistula access for chronic hemodialysis: A new approach

We are reporting a case of venous thoracic outlet syndrome with recurrent subclavian vein thrombosis in the setting of an ipsilateral brachiocephalic arteriovenous fistula for hemodialysis that was malfunctioning due to the central vein obstruction. The patient also had a concomitant external jugular vein origin stenosis. Given her body habitus and aversion to recovery after traditional first rib resection, we elected for an alternative treatment with an external jugular vein to internal jugular vein transposition with balloon angioplasty of the stenosed external jugular origin segment. The goal of this was to provide simultaneous relief of her outlet obstruction symptoms and salvage her dialysis access with a less invasive technique.

Bioarchaeological evidence of care provided to a physically disabled individual from Pachacamac, Peru

This paper presents a bioarchaeology of care case study based on the skeletonized remains of an elderly female with a congenital condition that compromised both mobility and independence in undertaking certain basic tasks, and which generated requirements for long-term care in the form of both direct support and accommodation. The remains show evidence of bilateral cervical ribs, severe osteoarthritic destruction in the right shoulder joint, and a healed skull trepanation. The remains were recovered from a cemetery dating to the initial part of the Late Intermediate Period at the archaeological site of Pachacamac, Peru. The subject has been identified as belonging to an Ychsma ayllu. This paper applies the bioarchaeology of care methodology in considering the implications of care provision within the Ychsma socialcontext, and suggests that caregiving may have been a relatively common practice in this complex society. This case study is a good example of how the application of social theory through the bioarchaeology of care approach can enrich bioarchaeological studies.

Thoracic Outlet Syndrome: A Comprehensive Review of Pathophysiology, Diagnosis, and Treatment

Thoracic outlet syndrome, a group of diverse disorders, is a collection of symptoms in the shoulder and upper extremity area that results in pain, numbness, and tingling. Identification of thoracic outlet syndrome is complex and a thorough clinical examination in addition to appropriate clinical testing can aide in diagnosis. Practitioners must consider the pathology of thoracic outlet syndrome in their differential diagnosis for shoulder and upper extremity pain symptoms so that patients are directed appropriately to timely therapeutic interventions. Patients with a definitive etiology who have failed conservative management are ideal candidates for surgical correction. This manuscript will discuss thoracic outlet syndrome, occurrence, physical presentation, clinical implications, diagnosis, and management.

Side-to-side elbow range of movement variability in an ulnar neurodynamic test sequence variant in asymptomatic people

Background:

Range of motion (ROM) asymmetry between sides is one indicator of a positive neurodynamic test, but this has been less well studied for the ulnar nerve.

Objective:

The purpose of this study was to investigate side-to-side variation in elbow ROM during an ulnar neurodynamic test sequence, including contralateral cervical side flexion, in 40 asymptomatic subjects.

Methods:

A traditional goniometer was used to measure elbow flexion ROM at two end points, onset of resistance (R1) and symptom onset (P1). Two repeated measures of R1 and P1 were taken on each side.

Results:

Reliability for R1 and P1 was found to be good (ICC ≥0.83, SEM ≤5.37) with no significant difference in mean ROM between sides. A significant relationship between sides was seen (r values ≥0.48) and R2 values >0.23; this indicates at least 23% of the variance observed in one limb was accounted for by range in the opposite limb. This relationship was slightly stronger for R1 than P1. Lower bound scores indicate that intra-individual ROM difference >23° for R1 and 22^° for P1 would exceed normal ROM asymmetry.

Conclusion:

These findings provide clinicians with background information of ROM asymmetry during the ulnar neurodynamic test.

Arterial thoracic outlet syndrome caused by cervical ribs-an unusual case report

RATIONALE

Cervical ribs are rare conditions, occurring in 0.05% to 3.0% of the population. This manuscript reports a case of arterial thoracic outlet syndrome (ATOS) associated with this congenital anomaly.

PATIENT CONCERNS

We report a 32-year-old female worker presenting pain in her left upper-extremity for 7 months. Her left hand became paler and cold when the temperature decreased, and the symptoms could not be eased through rest, physiotherapy and drugs medication.

DIAGNOSES

Compression of left subclavian artery with axillary and brachial arteries thrombosis was confirmed by duplex ultrasound and computed tomography angiography. ATOS caused by cervical ribs was confirmed by medical history, physical examination, and imaging.

INTERVENTIONS

The patients underwent acute thrombolysis and balloon angioplasty.

OUTCOMES

Symptoms of pain and weakness disappeared after surgery. The patient had not experienced any apparent symptom recurrence at 1-year follow-up.

LESSONS

Successful treatment of ATOS depends upon urgent assessment, accurate identification of causative factors and compression site and early diagnosis before the event of arterial thrombosis. The surgery combined with anticoagulation treatment can improve the treatment outcome of ATOS.

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.

Dynamic Compression of the Subclavian Artery Secondary to Clavicle Nonunion: A Report of 2 Cases

CASE

We describe 2 patients with nonunion of the clavicle and dynamic compression of the subclavian artery. In both patients, no structural abnormality of the subclavian vessels was evident at rest; however, with the arm in hyperabduction, arterial occlusion occurred because of the mobility of the fracture and a prominent callus.

CONCLUSION

This small case series demonstrates an important and, to our knowledge, unreported clinical complication of clavicle fracture nonunion. We believe that this complication is worth considering as a rare but important cause of pain in patients with delayed union or nonunion of the clavicle.

Synostosis of the first and second ribs in six horses

CASE DESCRIPTION Over a 2-year period, 6 horses (4 Selle Français, 1 Hanoverian, and 1 Thoroughbred) were referred for evaluation of forelimb lameness. All horses had radiographic evidence of synostosis of the first and second ribs (SFSR). CLINICAL FINDINGS For 1 horse, the SFSR was considered the probable cause of the lameness (grade 3/5), with a shortening of the cranial phase of the stride in the affected limb. For 3 horses, it was considered a possible cause of the lameness (grade 1/5) for the same reason. For 2 horses, SFSR was considered an incidental finding unassociated with any clinical signs. The 4 horses with lameness suspected as attributable to SFSR had a moderate to severe amount of irregularly marginated new bone formation at the site of the SFSR, with a cranial displacement of the first rib, compared with findings for the 2 horses in which the SFSR was considered incidental. A likely congenital abnormality of the first rib was first suspected on nuclear scintigraphy in the 1 horse for which it was performed or on radiography of the caudal cervical portion of the vertebral column (3 horses) or shoulder joint (2 horses). TREATMENT AND OUTCOME The horse in which SFSR was considered the probable cause of the lameness was retired to the field and remained chronically lame. Two of the 3 horses in which SFSR was considered a possible cause of lameness received an IV infusion of tiludronate disodium and mesotherapy over the caudal cervical and cranial thoracic regions; both returned to competition but with poor results. One of the 2 horses with subclinical SFSR never developed lameness on the affected side. No follow-up information was available for the other 2 horses. CLINICAL RELEVANCE SFSR can be an incidental finding in horses, with or without clinical manifestations. This abnormality should be considered as a differential diagnosis for horses with forelimb lameness and associated shortening of the cranial phase of the stride that fails to improve with diagnostic analgesic techniques.