Upper Extremity Vascular Exposure

Introduction

Vascular surgeons who treat thoracic outlet syndrome and perform arteriovenous (AV) access obviously regularly operate in the upper extremities, but expeditious and safe upper extremity exposure is required for the treatment of trauma, complex aortic endograft repair of aortic diseases, and many other conditions.

For purposes of planning exposure, it is convenient to divide the relevant upper extremity vessels into three zones ( Fig. 59.1 ). The intrathoracic zone contains the aortic arch, innominate artery, subclavian arteries on both sides, innominate veins, and superior vena cava. The importance of this classification is that exposure, although straightforward, requires more time than in the limb (see Ch. 55 , Thoracic and Thoracoabdominal Vascular Exposure). The sternum must be divided or the thorax opened. Therefore, in trauma cases, because it takes more time to expose the arteries, planning ahead and perhaps a more conservative and safer approach for proximal control should be considered. For venous reconstruction, although usually less emergent, somewhat complex exposure strategies are likewise needed. The next zone is essentially the thoracic outlet, extending from the base of the neck to the axilla, which contains the subclavian, proximal vertebral, and proximal axillary arteries and veins. This area contains critical nerves, which must be preserved, and the clavicle and to a lesser extent deltoid muscle can block access to certain parts of the vessels. Finally, the third zone is the arm itself, extending from the axilla to the fingers. Vascular exposure in the arm is usually much more straightforward, especially if the operative field is sufficiently distal so that a tourniquet may be used.

Exposure of Arteries Within the Thorax

In patients with normal anatomy, the first branch of the aortic arch after the coronary arteries is the innominate artery, which then bifurcates into the right subclavian and right common carotid arteries. Approximately 13% of patients have a “bovine arch,” somewhat inaccurately but commonly used to describe the situation where the left common carotid artery arises from the innominate itself or a common ostium; in most patients the left common carotid artery is the next separate branch from the arch, followed by the left subclavian artery. There are two critical variants. The first is an aberrant right subclavian artery. This situation, occurring in up to 2% of patients, is variable but most typically creates a situation where the innominate artery simply becomes the right common carotid artery, and the right subclavian artery arises as the last branch (usually from the descending aorta, now on the left side), passing behind the esophagus to supply the right arm. Although often asymptomatic, this abnormal artery is sometimes associated with aneurysmal degeneration (diverticulum of Kommerell) and/or can produce dysphagia via a mass effect (dysphagia lusoria) (see Ch. 78 , Thoracic and Thoracoabdominal Aortic Aneurysms: Etiology, Epidemiology, Natural History, Medical Management, and Decision Making). A second important variant is origination of the left vertebral artery from the aortic arch, occurring in 2%–5% of patients. Although this should specifically be identified ahead of time if direct intervention on this vessel is planned, its major significance lies in planning thoracic endovascular aneurysm repair, to avoid covering this vessel inadvertently. ^,

As described previously, especially with regard to trauma, control of intrathoracic vessels takes more time than elsewhere, and thus a slightly more conservative approach may be considered. Exposure of most extremity vessel injuries directly is straightforward because proximal control is not difficult, although if a supraclavicular injury occurs that is constrained, proximal control may not be possible at the site of injury itself. Although endovascular approaches can be used, surgical control will take much longer than in the arm itself. The implication of this is that if there is any question that control may be needed within the thorax (again, classically an injury to the subclavian artery with a supraclavicular hematoma), it is prudent to obtain this control first, before the injury is approached directly.

Exposure of the arch and proximal great vessels is required for debranching, aortosubclavian and carotid bypass for atherosclerosis or Takayasu arteritis, or occasionally complex AV access and in some trauma cases. In general, exposure of the innominate, proximal right subclavian, and proximal left carotid arteries should always be performed by means of median sternotomy. The proximal left subclavian artery can be reached via median sternotomy, although not quickly, so if such exposure is needed urgently an anterolateral third interspace thoracotomy is the preferred approach.

Innominate, Right Subclavian, and Left Common Carotid Arteries, and Proximal Left Subclavian Artery: Elective Situation

Median sternotomy provides superb exposure to these vessels, as well as to the ascending aorta. If the aorta does not need to be used, the sternotomy can be limited to the third interspace ( Fig. 59.2 ). Following sternotomy, the anatomy will be very well delineated. The left innominate vein is superficial and should be preserved but can be sacrificed in an emergency. Two nerves are critical to protect. The right recurrent laryngeal nerve loops around the right subclavian artery just as it arises from the innominate artery, and the phrenic nerve passes behind the jugular and right innominate vein and anterior to the right subclavian artery and anterolateral to the innominate artery. Both should be easy to identify, but both can be in jeopardy if indiscriminate circumferential dissection of the vessels is carried out without caution.

After teasing away fatty tissue and mobilization and retraction of the overlying veins, this approach yields ideal exposure to the orifice of the innominate and left common carotid arteries, the proximal portions of these arteries themselves, and, by extending the incision onto either side of the neck or the right supraclavicular area, the rest of both common carotid arteries and the right subclavian artery into the thoracic outlet, respectively ( Fig. 59.3 ). Exposure of the subclavian arteries will be limited by the sternocleidomastoid muscles (which can be partially divided, but ideally not fully transected) and anterior scalene muscle which can be fully divided (see later), but the vertebral arteries usually arise proximal to this and this approach can be excellent for proximal vertebral exposure. Finally, with further dissection, the proximal portion of the left subclavian artery (and left vertebral artery, if normal) can be reached through this incision. Again, caution should be taken with regard to the left recurrent laryngeal nerve; after looping around the aorta in the region of the ligamentum arteriosum, it ascends anterior to the arteries and can be within the surgical field.