Most upper extremity problems encountered by overhead motion athletes will involve the musculoskeletal structures around the shoulder joint, shoulder girdle, and cervical spine area. Vascular and neurologic conditions also occur in the cervical and scapulothoracic regions that sports medicine physicians and other health care professionals need to recognize. One such condition, axillosubclavian venous thrombosis, is unique to the thoracic outlet. It is a subset of thoracic outlet syndrome (TOS) known as effort thrombosis and often is referred to as Paget‐Schroetter syndrome (1). First described separately by James Paget in 1875 and von Schroetter in 1884, Paget-Schroetter syndrome was termed in 1949 by E.S. Hughes in his review of venous obstruction in the upper extremity (1).
Generally TOS is divided into two major types — neurogenic and vasculogenic. Neurogenic TOS is thought to be a result of anatomical compromise of the lower trunks of the brachial plexus (10). There exists some controversy regarding the diagnosis of neurogenic TOS based on the variability of test results and the lack of a true diagnostic marker (10,17). Vasculogenic TOSs derive from venous (vTOS) or arterial (aTOS) etiologies and demonstrate symptoms and signs that are usually consistent with vessel compromise (17). aTOS is associated usually with cervical or anomalous first ribs, scalene muscle hypertrophy, and congenital muscle bands in the posterior aspect of the thoracic outlet where the subclavian artery resides (17). vTOS is associated with compromise of the subclavian vein in the anterior aspect of the thoracic outlet where the costoclavicular ligament contributes to the narrowing at the costoclavicular junction (1,9).
There are three types of vTOS: intermittent or positional venous obstruction, primary thrombosis, which includes effort thromboses, and secondary thrombosis due to devices such as catheters or other instrumentation (9,17). Chronic intermittent obstruction can evolve into a primary spontaneous thrombosis if not recognized and corrected (9). Idiopathic thromboses are associated often with a hypercoagulable state such as congenital thrombophilia or underlying occult cancer.
vTOS resulting in a primary upper extremity deep venous thrombosis (UEDVT) is rare, occurring in approximately 2 per 100,000 people per year (27). Effort thrombosis accounts for 10% to 20% of those (1). It most commonly occurs in young adults between the ages of 18 and 30 years who are otherwise healthy. It is also more common on the right side, and 60% to 80% report exercise and activity involving the extremity such as overhead throwing, swimming, wrestling, gymnastics, or other activities that may require sustained and forceful upper extremity motion (1,7,9). Additionally certain occupations such as painter or auto mechanic appear to be at increased risk for developing vTOS (9). There are conflicting data regarding distribution between the sexes, with some reporting an equal distribution and others a 2:1 split of men to women (9,24). Primary vTOS in children or adolescents is rare and most cases are secondary. Thrombophilia may be higher on the differential, but age determinations on this are not clear. Malignancies such as lymphoma, Pancoast tumors, and osteochondromas have been reported in the literature as etiologies for vTOS. A list of conditions to consider in the differential diagnosis is in the Table (19,27).
The pathogenesis of an effort thrombosis involves a repetitive extrinsic compression of the subclavian vein that occurs with the shoulder in an abducted and externally rotated position (17,24). This repetitive motion can result in selective muscle hypertrophy. Specific examples include the hypertrophy of pectoralis minor that frequently occurs in competitive swimmers or the hypertrophy of the scalene muscles that can be seen often in weightlifters (9,10). Additionally the clavicle and costoclavicular ligament are anatomical landmarks that, in association with the surrounding hypertrophied muscles (anterior scalene, subclavius, and pectoral muscles) can lead to a fibrous stenosis of the subclavian vein at the level of the first rib. Repetitive motion worsens the problem of scar formation, and the intima is ultimately damaged narrowing the vein and presenting a thrombogenic surface (22,24). However venogram studies demonstrating intermittent venous outflow obstruction have shown that some cases of effort thrombosis occur without evidence of actual injury to the vein (9).
Certain underlying inborn conditions have been associated with increased risk of developing effort thromboses (17). Although relatively rare, they include known thrombophilic disorders such as Factor V Leiden, prothrombin gene mutations, and other less common disorders (1). However, in the athletic population, there does not appear to be any significant epidemiological reviews of inherited thrombophilic conditions that have been found to be causative for effort thrombosis.
The thoracic outlet is the area bordered by the clavicle superiorly, the first rib inferiorly, the subclavius muscle and costoclavicular ligament medially, and the anterior scalene muscle posteriorly. The subclavian vein passes anterior to the anterior scalene muscle between the first rib inferiorly and the clavicle superiorly, and just inferolateral to the subclavius muscle and tendon (Fig. 1). Muscle hypertrophy, fibrotic tissue changes, and repetitive trauma to the subclavian vein leading to fibrosis, inflammation, and intimal wall damage in this confined anatomical area all contribute to the potential for venous thrombosis (22,25).
Up to 80% of presenting patients report vigorous activity involving the upper extremities. This usually includes some type of repetitive overhead positions (hyperabduction) and/or heavy lifting (9). Patients sometimes experience subocclusive events that may precede the development of the occlusive thrombus. They are described frequently as intermittent episodes of pain in the affected arm, which are often less painful and usually without swelling when compared to complete occlusion (22). When a thrombotic event occurs, it usually is preceded by a sudden increase in the causative activity, and 85% of patients will develop symptoms within 24 h of the inciting event (9).
The presenting symptoms can vary among patients, often making recognition of an effort thrombosis difficult. Sudden onset of swelling and arm discomfort are undeniably the most common presenting symptoms. A feeling of “heaviness” in the arm is associated classically with complaints of swelling and cyanosis. Many patients complain of exercise fatigue of the affected arm, and the pain is generally worse with activity. Whatever the presenting symptoms may be, they are almost always persistent and severe (9,24). The identification of any of these signs or symptoms should heighten one’s clinical suspicion and prompt further workup.
The first step in diagnosing vTOS is recognizing the patient’s symptoms and identifying any clinical signs during the examination. A broad-based differential diagnosis for vTOS may be seen in Table 1. The physical examination should begin with visual inspection of the skin and local structures including the spine, chest, shoulder girdle, and upper extremities. The examiner typically will find a suffused upper limb with spreading discoloration that may be either cyanotic or erythematous. The discoloration sometimes may be described as reddish blue. Patients often have dilation of the superficial collateral veins of the upper arm, base of the neck, and the anterior chest — this is known as Urschel’s sign (1). The skin of a symptomatic arm often will exhibit a dusky discoloration. Other vTOS-related abnormalities include asymmetry, muscular atrophy or hypertrophy, or abnormal posturing of the patient.
Palpation should be used to identify any tenderness in the affected area and should include the supraclavicular fossa looking for any fibromuscular bands or signs of brachial plexus irritability. Additionally the neck and shoulders should be assessed for any active or passive range of motion deficits, and a neurovascular assessment also should be undertaken. Auscultation of the supraclavicular fossa with the arm in extreme abduction may reveal a bruit indicative of vasculogenic TOS. However a bruit is not always specific to vTOS and may be seen with aTOS (11).
Provocative testing is utilized frequently in cases of suspected TOS but suffers from a high rate of false positives, approaching 50%. The Wright hyperabduction test and the costoclavicular compression maneuver appear to be the most useful for vascular compression. The former is completed by having the patient turn his/her head away from the affected side and taking a deep breath while the examiner abducts and externally rotates the symptomatic arm. The latter involves the patient assuming an exaggerated military position with the shoulders drawn back and downward to reduce the costoclavicular space. Either test is considered positive if the radial pulse is obliterated or symptoms are reproduced (16). The problem with these tests is that they rely on the arterial pulse. Effort thromboses are a venous problem. Their utility may be better suited for cases of suspected arterial or neurogenic TOS and less so for affirming vTOS.
Laboratory evaluation is not necessary for the diagnosis of vTOS. Whereas the D-dimer test can assist in stratifying patients suspected of lower extremity deep venous thrombosis, no data on the D-dimer have been identified in the setting of any type of UEDVT, including effort thromboses (13). If there is high clinical suspicion, imaging should be pursued to confirm the diagnosis (21).
There are conflicting data on the association of thrombophilia and vTOS. This appears to be due to limited sample sizes and inclusion criteria. The association is reported to be as high as 67% and as low as 7% to 8% (3,8). There also are data to support the statement that thrombophilias are present equally in UEDVT cases with or without an antecedent effort history (3). It has been reported also that postoperative complications may be more associated with thrombophilias (13). The lack of consistency makes it difficult to give a definitive recommendation on the need for a thrombophilia work-up. However it appears reasonable to do so in cases where there are identifiable risk factors for future events such as the use of oral contraceptives or a strong family history or in cases of recurrent thrombotic events (13).
Visualization of a subclavian thrombus is necessary for the diagnosis of vTOS. Currently multiple different imaging modalities are available, and the selection often depends on an institution’s resources. Traditional plain film radiography is not diagnostic but may show boney structures such as a first rib abnormality or a cervical rib that are associated with an increased rate of TOS. Duplex ultrasonography can be diagnostic. It provides a sensitivity of 78% to 100% and a specificity of 82% to 100%, and the American College of Radiology considers this the best initial approach for direct evaluation of arm veins (4,20). It is the quickest, least invasive, and most inexpensive imaging modality that can be used for the diagnosis of vTOS. However there are some limitations, and it can have a false-negative rate of up to 30%. The superimposed clavicle and collateral veins being mistaken for the subclavian vein are two of the possible limitations of a duplex ultrasound in thoracic outlet (14). A negative Doppler ultrasound therefore should not be used to exclude vTOS if there is high clinical suspicion (9,21,24).
Catheter-directed contrast venography is recommended if noninvasive studies are inconclusive or intervention is planned. It should be performed in the neutral and abducted position and is considered the “gold standard” for the diagnosis of vTOS (14,18,20). With effort thrombosis, occlusion at the costoclavicular junction should be immediately obvious if a thrombus is present. In such cases, collateral vessels are seen typically (9). One major advantage of catheter-directed venography is that it is not only reliable for diagnosis but also allows for proceeding directly to thrombolysis.
Other imaging modalities have been used in some institutions but have not been studied sufficiently to be relied upon for the diagnosis of vTOS. Noncontrast computed tomography and magnetic resonance (MR) imaging have been disappointing in the evaluation of vTOS and should not be used. Contrast-enhanced MR venography is the most promising alternative imaging study. It may have the potential to become the noninvasive test of choice, as some early studies show up to 100% sensitivity and 97% specificity (1). Limitations include its high cost and limited availability. Current recommendations make MR venography a secondary imaging recommendation for vTOS (1).
There are few prospective studies identified for the treatment of effort thrombosis. This likely is due to the overall small numbers of effort thromboses making prospective study difficult. However a reasonable approach to the problem can be made with the following understanding: Acute presentations have better outcomes with immediate thrombolysis and early surgical intervention, with anticoagulation considered in the postoperative period (15,23,24). Additionally the longer the delay in definitive treatment, which some define as anything greater than 2 wk, the higher the risk for incomplete patency and successful resolution of symptoms (15,22).
The choice in management is complicated by many factors. These include the patient’s age, involvement of the dominant arm, desire to return to prior level of activity (whether that involves sport, occupation, or hobby), and the duration of thrombus (13,22–24). The presence of any complications such as a pulmonary embolism also may complicate management decisions. Fortunately pulmonary emboli are often less debilitating when compared with emboli from the lower extremities, but these still have an incidence of 10% to 20% (22,24). The presence of a thrombophilia also may influence the choice of treatment (22). Additionally when underlying anatomical abnormalities are not corrected, the risk of recurrent thrombosis is increased (24). Therefore surgical intervention is currently considered a central component in the definitive approach to effort thrombosis (9,24,26).
Nonoperative management for vTOS is arm elevation with anticoagulation (Fig. 2). This method of treatment has an incidence of complications between 39% and 68% (2,12). These include persistent symptoms and disability (9). Catheter-directed thrombolysis (CDT) is added in some cases of non-operative management. This also may include endovascular venoplasty. In the postprocedural period, anticoagulation is initiated and is followed by a venogram to confirm patency. It should be noted that the specific duration for anticoagulation in medically managed effort thrombosis is not known. It is thought that since effort thrombosis is a result of compression and fixed anatomical changes, and these problems are not addressed permanently that patients may require lifelong anticoagulation if not surgically corrected (23). The risk for reoccurrence in this setting is estimated to be between 50% and 60% (24).
If the patient elects surgical intervention, a plan for treatment should be made based not only upon the previously mentioned concerns but also whether the presentation is acute, subacute, or chronic. The surgical interventions involve the resection of the first rib and an anterior scalenectomy, with various approaches discussed in the literature (23). The most common approaches are via the transaxillary or supraclavicular route. Each approach has its benefits depending on plans for percutaneous venoplasty or open venous reconstruction and simultaneous efforts to minimize disruption of the pectoral muscles (22,26).
With an acute presentation, the literature reports a 100% success rate when CDT is followed by surgery with venoplasty during the same hospitalization (15). In cases when surgery is not available immediately, CDT is still recommended as the first step (9). Patients are anticoagulated frequently at this point while awaiting surgery, but the timing of surgical intervention is less definitive. With Machelder’s 1993 article (12), the recommendation was 3 months. However concerns over restenosis prior to surgery were raised because this reduced Machelder’s success rate (12) from 93% to 64%. Urschel and Patel (26) demonstrated success in 96% of patients treated within 6 wk, and the second arm of the study of Bamford et al. (2) demonstrated that an operative window of 40 d resulted in 100% success. Unfortunately the study had a methodology change that lessens the strength of those results. However it seems apparent that surgical intervention in the subacute phase prior to 6 wk will maintain favorable outcomes and is safe.
Patients with a chronic occlusion appear to be served best with the same approach for acute cases (thrombolysis with surgery), although the results are not as good. Urschel and Patel (26) studied a group of 42 patients that presented more than 6 wk after occlusion that were treated with thrombolytics and surgery. Fifty-seven percent had successful patency and 20% had no patency or collateralization. The delay in surgery and absence of open venoplasty may explain some of these outcomes, in his study.
A final group of patients have chronic intermittent obstruction but no current thrombus identified by either duplex ultrasound or venography. They can be treated successfully by proceeding directly to surgery. In a 2009 study, all patients treated this way were asymptomatic at 9 months (5).
In the postoperative period, there is good support for the use of a venogram within 2 wk of surgery to evaluate for any restenosis or thrombus regardless of the patient’s symptoms (5). If the venogram demonstrates another thrombus, then CDT is recommended and endovascular venoplasty may be considered. If the venogram demonstrates narrowing without residual thrombus, then anticoagulation can be recommended. In both cases, follow-up imaging for improvement will be necessary. No anticoagulation can be recommended if the venogram is patent without narrowing or constriction based upon recently published data (2). It may be reasonable to confirm the mechanism as being truly effort related and that no thrombophilia is present when contemplating this decision.
It should be noted also that there has been no published data regarding the use of newer generation oral anticoagulants in the treatment of effort thrombosis. Molina et al. (15) and Thompson (24) separately utilized clopidogrel and warfarin postoperatively, and many other studies have utilized aspirin in the postoperative period (2). This appears to be an area for further investigation.
Return to Play
The discussion regarding return to play is somewhat limited in the literature and requires a multifaceted approach. Much of the research does not focus strictly on athletes, even when the presentation was effort induced, due to overlap with some occupational etiologies. However the publications that did discuss return to sport had much in agreement. The consensus appears to be around 12 wk after successful definitive intervention and discontinuation of anticoagulation (6,14,22). Most therapy programs start at this time. However one study began light throwing while still on anticoagulation and progressed after discontinuation (6). Melby et al. (14) began early gentle range of motion exercises in the more immediate postoperative period. There was nothing to suggest that waiting longer was either beneficial or detrimental to the eventual outcome in these cases, and the athlete returning to full activity was the norm.
Identifying vTOS requires a high index of suspicion and a definitive diagnosis be obtained either with ultrasound or venography if immediate thrombolysis is planned. If the condition is effort induced, it will have an increasing morbidity the longer treatment is delayed. Currently preoperative thrombolysis with corrective surgery is the standard of care with an emphasis on obtaining definitive treatment as early as possible. For athletes in the postoperative period, controlled rehabilitation may be started early on. Return to prior levels of activity in athletes with restored patency should be expected.
There are no funding disclosures or conflicts of interest to declare.
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