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Blunt Arterial Injuries of the Shoulder: Open and Endovascular Therapy
The major vessels injured with shoulder girdle trauma are the axillary and subclavian arteries. The muscles and bones of the shoulder girdle, which surround these vessels, provide considerable protection against injury. Thus, blunt injuries to the axillary and subclavian arteries are relatively unusual, and most series of upper extremity arterial injuries report that a majority are caused by penetrating injury and involve the brachial artery and its branches. Blunt arterial injury to the axillary or subclavian artery accounts for only 7% to 10% of all arterial injuries to the upper extremity.
The types of blunt trauma that result in axillary and subclavian artery injury include hyperabduction of the arm, shoulder dislocation, scapulothoracic dissociation, and fracture of the first rib or clavicle. Hyperabduction of the arm can result in avulsion of arterial branches of the axillary and subclavian arteries, transection of the arteries, or disruption of intima by stretch injury. Intimal injury or disruption of the vessel wall can in turn result in vessel thrombosis, embolism, or pseudoaneurysm formation.
Shoulder dislocations typically do not result in arterial injury. When arterial injury does occur, it is most often associated with anterior dislocations in elderly persons. Such patients likely lack elasticity of the vessel. Consequently, the artery cannot accommodate the stretch caused by the dislocation. Axillary artery injury can also occur during reduction of chronic shoulder dislocations. Under these circumstances, scarring and atherosclerosis act to fix the vessel, and the axillary artery cannot accommodate the additional stretch needed during the traction required to reduce the dislocation. Scapulothoracic dissociation occurs after severe crush or traction injury to the shoulder and is associated with subclavian and/or axillary artery injury. Fractures of the first rib and the clavicle occasionally impinge on the underlying subclavian artery.
The branches of the subclavian and axillary arteries provide an extensive arterial collateral network around the shoulder. As a result, signs and symptoms of ischemia might not be evident even if the axillary or subclavian arteries are occluded or transected. Because the brachial plexus is in close proximity to the distal subclavian and the axillary arteries, blunt shoulder trauma often results in injury to these nerves. The axillary vessels and the brachial plexus are surrounded by an extension of the prevertebral layer of the deep cervical fascia in the arm. Bleeding into this sheath can cause significant compression of the brachial plexus, which can result in brachial plexus damage.
Presentation and Diagnosis
Patients with shoulder trauma can come to the hospital with signs and symptoms of arterial insufficiency of the upper extremity, an expanding hematoma, a pulsatile mass, signs of ongoing hemorrhage, or hemothorax. However, because of the rich collateral circulation around the shoulder joint, some patients with significant arterial injuries come to the hospital with minimal or no signs of upper extremity ischemia; they can even have palpable wrist pulses. Signs of hemorrhage can be difficult to appreciate, especially in muscular or obese patients. Therefore, one must have a high index of suspicion to make an early diagnosis of a vascular injury.
Blunt arterial trauma is less likely to result in hemodynamic instability. Patients who come to the hospital with hard signs of vascular injury such as pulsatile bleeding, expanding hematoma, palpable thrill, or evidence of peripheral ischemia should be taken to the operating room without delay. At operation, either an intraoperative angiogram or exploration of the injury is done depending on the hemodynamic stability of the patient and the surgeon’s expertise and preference. In patients without obvious signs of arterial injury, the presence of associated shoulder injuries often provides a clue regarding the presence of an underlying vascular injury. Clavicular fracture, shoulder dislocation, first rib fracture, brachial plexus injury, scapular fracture, or proximal humeral fracture increase the likelihood of an associated major arterial injury. Often, nerve root avulsion causes a devastating brachial plexus injury when the arm is forcibly hyperabducted. Additionally, compression of the brachial plexus by hematoma within the neurovascular sheath can also cause substantial neurologic impairment. In all cases, prompt exploration is indicated.
Arteriography has been the cornerstone for diagnosis of arterial injury associated with blunt shoulder trauma ( Figure 1 ). Computed tomography (CT) angiography has largely replaced conventional arteriography for initial evaluation of arterial injuries. All patients who are hemodynamically stable and come to the hospital with signs of upper extremity arterial insufficiency should undergo an imaging study. Such is useful to plan the best operative approach, especially when a proximal subclavian artery injury is identified. A potential advantage of conventional arteriography is that after vascular access has been obtained, the surgeon may consider endovascular options to treat the identified injury.
Patients with axillary or subclavian artery injuries commonly have other concomitant injuries. Treatment priorities for the other injuries need to be established. Because of the excellent arterial collateral circulation around the shoulder, the upper extremity is often at less risk for severe ischemic sequelae. Therefore, treatment of other life-threatening injuries can and should be given priority over arterial repair. However, vascular reconstruction should not be excessively delayed.
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