Dynamic neuromusculoskeletal ultrasound documentation of brachial plexus/thoracic outlet compression during elevated arm stress testing

Background

The diagnosis and validation of thoracic outlet syndrome/brachial plexopathy (TOS) remains a difficult challenge for surgeons, neurologists, and radiologists. This is due to the fact that the responses of standard elevated arm stress tests can be considered somewhat subjective and can vary. Therefore, non-vascular TOS cases are presently diagnosed clinically, and any objective diagnosis has been controversial.

Methods

This is a technique paper describing the use of dynamic neuromusculoskeletal ultrasound to assist in the diagnosis of thoracic outlet/brachial plexus pathology. We propose a new way to observe the brachial plexus dynamically, so that physical verification of nerve compression between the anterior and middle scalene muscles can be clearly made at the onset of clinical symptoms. This gives a way to objectively identify clinically significant brachial plexus compression.

Results

Dynamic testing can add objective analysis to tests such as the elevated arm stress tests and can correlate the onset of symptoms with plexus compression between the anterior and middle scalene muscles. With this, the area of pathologic compression can be identified and viewed while performing the dynamic testing. If compression is seen and the onset of symptoms ensues, this is a positive confirmatory test for the presence of TOS and a clinically significant disease.

Conclusions

This paper offers a simple, objective, and visual diagnostic test that can validate the presence or absence of brachial plexus compression during arm elevation in patients with brachial plexus injury and thoracic outlet syndrome.     

Reciprocal compression between the axillary artery and brachial plexus

Angiographic studies were performed on 60 of 394 patients diagnosed as having thoracic outlet syndrome. Ten of the patients studied angiographically presented with obstruction of contrast material in the axilla with refilling of the axillary artery through the external mammary and shoulder arteries. The obstruction was caused by lower trunk brachial plexus compression. This seldom known cause of hyperabduction syndrome occurred in 2.5 per cent of the patients examined for thoracic outlet syndrome. Surgical treatment consists of loosening the axillary artery by tying off the external mammary and circumflex arteries, followed by section and anastomosis of the axillary artery anteriorly to the brachial plexus. Angiography is considered a basic diagnostic procedure, mainly when concomitant compression occurs and gives good dynamic information on the location and importance of the compression.     

Thoracic outlet syndrome

Thoracic outlet syndrome (TOS) is an often misdiagnosed cause of neck, shoulder, and arm disability. Neurovascular compression may be seen in the interscalene triangle, costoclavicular space, or posterior to the pectoralis minor, although any cause of abnormalities of shoulder girdle alignment may cause a localized area of brachial plexus compression. Nerve compression in this way may lead to upper extremity weakness, pain, paresthesias, and numbness. A careful and detailed medical history and physical examination are essential to proper identification of thoracic outlet syndrome, which remains primarily a clinical diagnosis. Diagnostic testing may differentiate other causes of pain or neurologic symptoms of the upper extremity from TOS. Clinical management is often challenging.     

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

Background  

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

Thoracic outlet syndrome

Thoracic outlet syndrome (TOS) consists of a group of distinct pathologies arising as a result of compression of structures at the thoracic outlet. The structures at risk are, from anterior to posterior, the subclavian vein, subclavian artery and brachial plexus. Compression or impingement causes venous (VTOS), arterial (ATOS) or neurogenic (NTOS) TOS. NTOS is the most common presentation, caused by compression of the brachial plexus at the scalene triangle or pectoralis minor space. Other compression syndromes at the carpal and cubital tunnels should be excluded. Management is usually conservative, employing physiotherapy and postural exercises, but pain or muscle wasting may be indications for surgery. VTOS is caused by compression of the subclavian vein at the costoclavicular junction, resulting in venous thrombosis, the Paget-Schroetter syndrome, often as a result of exercise in fit young muscular people or musicians. Positional swelling of the upper limb without thrombosis is termed McCleery's syndrome. In the presence of thrombosis, clot lysis, first rib excision and venoplasty may be indicated. ATOS occurs due to compression of the subclavian artery at the scalene triangle, often in association with an anomalous bony structure, such as cervical rib, causing post-stenotic aneurysmal dilation of the artery, thrombosis and embolization. Acute upper limb ischaemia necessitates urgent cervical rib excision and arterial reconstruction.     

Complete cervical rib. Possible neurovascular implications of the upper limb

The thoracic outlet syndrome (TOS) is caused by compression of the brachial plexus or subclavian artery or vein in the region of the neck and shoulder girdle. The neurovascular bundle may be compressed at multiple sites: costoclavicular space, interscalene triangle, insertion of the pectoralis minor into the coracoid process. More than 90% of the patients present with neurologic symptoms: pain, paraesthesias or arm and hand weakness and 10% also have vascular problems. The diagnosis of TOS is always difficult and depends on careful clinical study of patients. For the neurological type of TOS, electromyograms, arteriograms and venograms are not helpful. The value of Doppler study and of arteriography is demonstrated in the present case of a woman with a five month history of pain and paraesthesias of the arm and hand, who shoved sudden occlusion of left humeral artery. Roentgenograms showed the presence of a well developed left cervical rib. Doppler study and arteriography showed the compression of subclavian artery with the arm abduction manoeuver. After first rib resection and humeral artery thrombectomy there was a complete return of humeral artery flow and of all neurologic functions. Thus the role of first cervical rib or other bone and muscular structures must be emphasyzed both in the brachial and in the subclavian artery or vein compression. Embolization of the axillary or humeral artery should be corrected as soon as possible when the cervical rib is corrected.     

Thoracic outlet syndrome in whiplash injury.

Thirty-five cases of thoracic outlet syndrome complicating whiplash or cervical strain injury were studied. Thirty cases had confirmation by the demonstration of slowed ulnar nerve conduction velocity (UNCV) through the thoracic outlet. Two distinct groups of patients were found. An acute group, seen an average of 3 1/2 months post injury, had severe neck pain with often mild or incidental thoracic outlet syndrome. A chronic group, with symptoms persisting more than 2 years after cervical injury, often had thoracic outlet symptoms as the predominant complaint. This study suggests that the arm aches and parethesias seen in association with both acute and chronic cervical strain injury are most often secondary to thoracic outlet syndrome.     

Diagnosis and treatment of thoracic outlet syndrome

Patients who develop symptoms of thoracic outlet syndrome (TOS) have a predisposing anatomic abnormality. In most patients with TOS, the symptoms are caused by entrapment of the brachial plexus and they do not arise from compression of the subclavian artery, as was previously thought. The tests advocated for diagnosing this common syndrome (i.e., evaluating the positional compression of the artery when the arms are raised, the neck is turned, or the shoulders are braced) cannot accurately diagnose this syndrome. There are two reasons for this. The symptoms of TOS are not related to the compression of the artery in the outlet in 98% of patients, and 75% of normal individuals without symptoms show diminished radial pulse on various provocation tests. We employed four timed provocation tests (minute tests) to diagnose TOS: the timed Morley test, timed Wright test, timed Eden test, and elevated arm stress exercise, all of which are very sensitive. In normal individuals without symptoms, 20% experience transitional symptoms such as slight pain and tiredness, on these tests indicating a subclinical state. TOS is treated by keeping the thoracic outlet wide, this being done either conservatively or surgically. In 1993 and 1994, we conservatively treated 418 of 422 patients with TOS by means of active exercise, a brace, and by block therapy. These measures did not reduce the symptoms in 23 of these patients, so surgical treatment was indicated. In the remaining 4 of the 422 patients, conservative treatment was not indicated and surgery was performed directly. All the patients showed significant clinical improvement of varying degree. Presented at the 69th Annual Meeting of the Japanese Orthopaedic Association, Tokyo, April 12, 1996     

Thoracic outlet syndrome after the Nuss procedure for the correction of extreme pectus excavatum

Since the Nuss procedure was introduced in 1998, many complications have been reported, but not thoracic outlet syndrome. Here we report a 13-year-old boy with pectus excavatum who had thoracic outlet syndrome develop after a modified Nuss procedure. The major modification from the original technique was the use of an additional bar to resolve his long, asymmetric deformity. The patient showed clinical features of brachial plexus compression. The abrupt structural and spatial changes induced by the marked elevation of the upper depressed chest might have given rise to this condition. Thoracic outlet syndrome is a possible complication of the Nuss procedure.     

Thoracic and vascular aspects of thoracic outlet syndrome. 1986 update

Upper extremity symptoms of arterial or venous origin are a rarer manifestation of the thoracic outlet syndrome than those caused by brachial plexus compression. Since the authors' original report in 1967, a better understanding of the necessity for detailed history and physical examination preoperatively and advances in angiography and computed tomography have made the selection of patients for thoracic outlet decompression and vascular reconstruction more reliable. Refinement in vascular surgical techniques and the advent of effective thrombolytic therapy have made the results of therapy more consistent. First rib resection and scalenectomy are curative for the majority of patients whose symptoms are caused by compression of the brachial plexus. Removal of the embologenic focus with vascular reconstruction and thoracodorsal sympathectomy are generally required in the presence of subclavian artery compression or aneurysm producing peripheral emboli. In patients who have venous compromise, thrombectomy or thrombolytic therapy and relief of subclavian venous compression may minimize future disability.     

颈横动脉对臂丛神经影响的应用解剖

目的探索臂丛的周围血管——颈横动脉是否对臂丛神经造成卡压以及解决的方法。方法选用陈旧性成人尸体31具62侧,在胸廓出口部位进行颈横动脉的应用解剖学研究,重点是它与臂丛神经的关系。结果13侧未见颈横浅动脉,49侧中出现51条颈横浅动脉,其中11条与臂丛神经有紧密接触,占21.15%。16侧未见颈横深动脉,46侧有52条颈横深动脉（肩胛背动脉）,其中31条与臂丛神经密切接触,9条在臂丛神经上留下明显压迹,占17.31%。结论颈横动脉,尤其是颈横深动脉（肩胛背动脉）可以形成对臂丛神经的卡压,是又一个可能导致胸廓出口综合征的原因之一。     

胸廓出口综合征手术治疗中对前中小斜角肌的处理

目的随访35例胸廓出口综合征手术治疗的疗效。方法手术治疗35例37侧胸廓出口综合征患者,其中上干型5例,下干型28例30侧,全臂丛型2例。X线片示颈肋1例,第七颈椎横突过长3例。手术切除增长的骨组织和颈肋,术中发现35例均有纤维束带压迫臂丛神经,均作前、中、小前斜角肌切断术。术后随访1年～3年6个月。结果术后症状明显改善26例27侧,部分改善5例6侧,无效4例。结论斜角肌是引起臂丛神经血管受压征的主要因素,手术探查时应常规切断前、中斜角肌及小斜角肌。     

Anomalous vasculature as direct cause of upper brachial plexus thoracic outlet syndrome

Direct vascular etiologies of upper plexus thoracic outlet syndrome (TOS) other than the subclavian vessels are exceptional. This is a unique case of an anomalous artery and its accompanying vein causing direct compression to the upper brachial plexus causing TOS. All symptoms resolved after successful treatment consisting of ligation and resection of the vessels. This case demonstrates that although direct vascular etiologies causing upper plexus TOS are extremely uncommon, they should be considered in the differential diagnosis.     

First rib fracture: a hallmark of severe trauma.

First rib fractures occurred in 55 patients. This injury is a harbinger of major trauma with 35 patients suffering a major chest injury, and abdominal and cardiac injuries occurring in 18 and eight patients respectively. The mortality associated with this injury was high (36.3%). Neurologic lesions accounted for the majority of deaths, however, unrecognized abdominal injuries and pulmonary complications were significant causes of mortality. Brachial plexus injury (5) and Horner's syndrome (3) occurred in survivors. Three patients had an associated injury of the subclavian artery, and the importance of this association is stressed. One late-developing post-traumatic thoracic outlet syndrome occurred. A fracture of the first rib is a hallmark of severe trauma; its presence should alert the clinician to: 1) generalized massive trauma with abdominal, chest, and cardiac injuries; 2) local injury to the subclavian artery and brachial plexus and; 3) necessity of long-term followup for late-developing sequelae.     

An unusual case of neurogenic thoracic outlet syndrome

IntroductionNeurogenic 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.DiscussionThough 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.ConclusionSurgical 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.     

Facial pain and headache associated with brachial plexus compression in the thoracic inlet

Among the sources for confusion related to brachial plexus compression in the thoracic inlet are the name for this clinical entity (thoracic outlet syndrome) and the fact that some of its associated symptoms occur outside the upper extremity, such as face and neck pain (FP) and occipital headaches (OH). With the realization that scalenus anticus (SA) contraction is the primary source of brachial plexus compression, it is possible to understand the occurrence of both FP and OH in this syndrome. It was hypothesized that SA contraction compresses the cervical plexus as it exits deep to this muscle. Furthermore, it was hypothesized that tension on the origin of this muscle from the transverse cervical processes causes compression of the occipital nerves. To evaluate this, a consecutive series of 32 patients who had resection of the SA between January 2004 and December 2007 were evaluated to determine prevalence of FP and OH, and the extent to which these symptoms were relieved postoperatively after SA resection. It was found that 25% of the patients had FP and that 50% had OH. Postoperatively, for those patients with neck pain, with or without facial pain, 75% were completely relieved, 18% were partially relieved. OH was completely relieved in 81% and partially relieved in 13% of the patients. In conclusion, symptoms of FP and OH associated with brachial plexus compression is due to cervical plexus compression by SA muscle, and symptoms can be relieved by resection of the SA.     

胸廓出口综合征的新认识——解剖学与临床观察

目的探讨胸廓出口综合征的病因。方法对３０具６０侧经福尔马林固定的成人尸体小斜角肌及前中斜角肌的起始部进行解剖研究;对５３例胸廓出口综合征手术患者（１９６６～１９９４年４５例,１９９６～１９９７年８例）随访情况进行总结分析。结果解剖研究发现小斜角肌的出现率为８８３％,Ｔ１神经根或其下干在小斜角肌近段起源的腱性组织上跨过;前中斜角肌在颈椎横突的前后结节均有起点,Ｃ５、Ｃ６神经根从前中斜角肌的交叉腱性起点中穿过。４５例１９６６～１９９６年手术者中,有颈肩痛症状者３４例,术后１７例颈肩痛症状仍存在,其中７例加重;８例１９９６～１９９７年手术者中,７例有颈肩痛,术中切断前中斜角肌在Ｃ５～６神经根旁的腱性纤维组织,术后仅有１例仍有颈肩部不适。结论小斜角肌的腱性纤维是臂丛神经下干或Ｔ１神经根受压的原因;前中斜角肌在Ｃ４～５横突前后结节的交叉腱性起点是压迫Ｃ５～６,有时包括Ｃ７神经根或臂丛神经上（中）干的原因     

Unusual case of thoracic outlet syndrome caused by a neurilemmoma in the pectoralis minor space

A 34-year-old man presented with a 5-year history of paraesthesia of the right palm and the right middle and ring fingers. This paraesthesia was exacerbated by elevation of the right arm. A tumour was palpable in the subclavicular fossa. As magnetic resonance imaging (MRI) indicated a neurogenic tumour originating from the brachial plexus, a diagnosis of thoracic outlet syndrome caused by a neurilemmoma in the pectoralis minor space was made. Pathological examination showed the tumour to be a benign neurilemmoma. There have been only three previous case reports of neurilemmomas as causes of thoracic outlet syndrome worldwide, and this is the first report of a neurilemmoma originating from the lateral fascicles of the brachial plexus in the pectoralis minor space causing thoracic outlet syndrome.     

Ultrasonography-guided osteopathic manipulative treatment for a patient with thoracic outlet syndrome

Patients with thoracic outlet syndrome can be treated with osteopathic manipulative treatment (OMT) to alleviate dysfunction and restriction of the pectoralis minor muscle (PMM) and the resulting compression of the brachial plexus. Neuromuscular ultrasonography (US) can demonstrate abnormalities in the thoracic outlet that are amenable to OMT and can be used to monitor intervention. The present report identifies PMM deformation and brachial plexus compression in a 32-year-old woman with thoracic outlet syndrome who was treated successfully with OMT. Neuromuscular US results were used to measure the degree of PMM deformation with the pectoral bowing ratio and confirm the diagnosis. Osteopathic manipulative treatment was applied and monitored using neuromuscular US to confirm that the operator's manipulating hand had direct contact with the PMM. Symptoms abated immediately after treatment. Results of a second neuromuscular US examination showed that the pectoral bowing ratio decreased into the normal range and thus confirmed that PMM deformation had resolved.     

Thoracic outlet syndrome

Thoracic Outlet Syndromes (TOS) consists of a group of distinct pathologies arising from compression or impingement of structures at the thoracic outlet. The structures at risk are, from anterior to posterior, subclavian vein (venous — VTOS), subclavian artery (arterial — ATOS) and brachial plexus (neurogenic — NTOS). NTOS is the most common presentation, usually caused by compression of the brachial plexus at the scalene triangle or pectoralis minor space. Neurogenic compression syndromes at the carpal and cubital tunnels should be excluded. Management of NTOS is usually conservative, employing physiotherapy and postural exercises, but pain or muscle wasting may be indications for surgery. VTOS is caused by compression of the subclavian vein at the costoclavicular junction, resulting in venous thrombosis (Paget—Schroetter syndrome) often as a result of exercise in fit young muscular people or musicians. Positional swelling of the upper limb without thrombosis is termed McCleery's syndrome. In acute thrombosis, clot lysis, first rib excision and venoplasty may be indicated. ATOS occurs due to compression of the subclavian artery at the scalene triangle, often in association with an anomalous bony structure, such as cervical rib, causing post-stenotic aneurysmal dilation of the artery, thrombosis and distal embolization. Acute upper limb ischaemia necessitates urgent cervical rib excision and arterial reconstruction.