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Answer: Subclavian Artery Aneurysm Secondary to Cervical Rib
The surgical anatomy of the subclavian artery is routinely described in 3 distinct sections. The first or most proximal part of the artery extends to the medial border of the anterior scalene muscle. This portion of the artery gives rise to the internal mammary artery, vertebral artery, and thyrocervical trunk and is affected by thoracic outlet compressive syndromes only secondarily by retrograde propagation of thrombus. The second portion of the subclavian artery is retroscalene. This is often the site of stricture and positional compression and, when present, the proximal area of dilation or aneurysm formation. Finally, the third part of the subclavian artery extends from the lateral border of the anterior scalene to the lateral border of the first thoracic rib.1
Although the first description of arterial complications secondary to anatomic variations in the thoracic outlet was published in The Lancetin 1861,2recognition that such vascular injuries were the consequence of repetitive motion and cumulative trauma did not come until recently.3,4Patients manifesting symptoms of arterial thoracic outlet syndrome are often young, healthy active individuals (manual laborers, athletes, etc), and, although not seen in all cases, anatomic variations such as cervical ribs, supernumerary scalene muscles, or persistent fibrocartilaginous bands often play an important role in these arterial compressive syndromes.5,6
Patients with arterial compression syndromes of the thoracic outlet will often first present with unilateral cold hypersensitivity, Raynaud phenomenon, and/or edema of the hand. This is often initially misdiagnosed as collagen vascular disease. Fingertip pain, cold-induced ischemia, and punctate ulcers, usually at the paronychial area, can occur as the disease progresses. With complete occlusion of the axillosubclavian artery, patients may report easy fatigability in the affected limb and worsening of symptoms with exercise.
Diagnosis of arterial compression at the thoracic outlet requires arteriography in almost all cases. Both the degree of stenosis and aneurysmal dilation can be evaluated; however, this diagnostic modality can underestimate the luminal irregularities subsequently found at the time of operation (Figure 3). Prompt operative intervention is necessary in these patients to prevent complete arterial occlusion and/or obliteration of the outflow vessels to the hand by repeated embolization. The standard approach is decompression of the thoracic outlet with first thoracic rib removal and scalenectomy. Cervical ribs and fibrocartilaginous bands are also resected when present. Vascular reconstruction with either direct repair or interposition graft is required when there is complete occlusion, aneurysm, or poststenotic dilation. This patient underwent thoracic first rib resection, scalenectomy, cervical rib resection, and arterial reconstruction with reversed saphenous vein from the left lower extremity.
Intraluminal ulceration in resected subclavian artery specimen.
Patients with symptoms consistent with arterial compression at the thoracic outlet should have their diagnosis confirmed promptly by arteriography before irreparable damage to the outflow vessels occurs. Surgery must consist of both decompression of the thoracic outlet and arterial reconstruction when significant dilation or intraluminal abnormalities are present. With aggressive management, patients can expect excellent clinical results and a return to normal physical activity.1
Correspondence:David J. Caparrelli, MD, Department of Surgery, The Johns Hopkins Medical Institutions, Blalock 618/600 N Wolfe St, Baltimore, MD 21287 (email@example.com).
Accepted for Publication:May 2, 2005.
Image of the Month—Diagnosis. Arch Surg. 2006;141(5):514. doi:10.1001/archsurg.141.5.513-b
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