UE Dissection Flashcards
Exposure of Brachial Artery at its Bifurcation
The mid or distal brachial artery is exposed through an incision over the medial biceps groove. The basilic vein and cutaneous branches of the median nerve are located within the subcutaneous tissue and should be identified and preserved during the dissection. Injuries to the median antebrachial cutaneous nerve can lead to pain or numbness along the medial and dorsal surfaces of the forearm, which can be debilitating. Once subcutaneous tissues are divided, the brachial sheath is then incised longitudinally. The median nerve is located medial and is the most superficial structure encountered. It is gently mobilized and retracted to allow access to the brachial artery. If the proximal radial or ulnar arteries require exposure, a lazy-S–shaped incision is recommended. Vertical incisions can heal with a contracture of the elbow and are generally not used. The median antecubital vein is preserved so it may be procured for a vein patch. The dissection is continued distally until the ulnar and radial arteries are encountered. The ulnar artery branches from the brachial artery medially and dives shortly after its takeoff beneath the pronator muscles
Indications for intervening on supra-aortic trunk lesions are include:
1) symptoms associated with ipsilateral >70% lesions or the irregular plaque 2) the same lesions with ipsilateral carotid artery disease requiring repair, and 3) pre-occlusive lesions in good surgical candidates with 5-year life expectancy.
What is Raynaud’s Syndrome
the most common vasospastic disorder seen in clinical practice. He proposed that vasospasm was caused by sympathetic nervous system overactivity. However, most patients never have manifestations as severe as gangrene, and the entity is now referred to as Raynaud’s syndrome (RS) by most vascular specialists. It is considered primary if there is no underlying disorder and secondary if it is a manifestation of an underlying or systemic condition.
Demographics of Raynaud’s
The true prevalence of RS is unknown, but in the United States it has been estimated to affect approximately 5% of the population, and the incidence may be increased in populations living in cooler climates. The large majority of patients with RS (89%) have primary RS. The phenomenon affects women more than men in a ratio of 4:1. The typical age of onset is between 10 and 30 years. There is evidence of familial aggregation of RS.
Red, White, Blue
The typical discoloration of digits has been referred to as the patriotic colors, with white, blue, and red phasic color changes. If vasospasm is severe, there is little or no blood flow to the digits, and they can appear cadaveric white. If vasospasm is moderate, flow may be sluggish, imparting a blue or cyanotic color to the fingers. On rewarming, hyperemia often develops, causing a reddish color in the digits.
Clinical Manifestations
The major clinical manifestation is the patient’s description of episodes of phasic color changes of the fingers, typically provoked by cold exposure or emotional stress. In addition to discoloration of the fingers, associated symptoms include numbness, paresthesias, and pain or an aching sensation. Typically the fingers are involved, and toes may be affected. Only rarely are toes involved without involvement of the fingers. Approximately 98% of patients report that exposure to a cold environment precipitates symptoms
Primary vs Secondary
Secondary Raynaud’s syndrome may be associated with collagen vascular diseases, hypothyroidism, hyperviscosity syndromes, and many other entities (Box 1). Among rheumatologic diseases, the incidence of RS varies, occurring in approximately 90% of patients with scleroderma and 30% of patients with systemic lupus erythematosus. In secondary RS, particularly with scleroderma and CREST syndrome, manifestations include severe pain, skin ulceration, and tissue infarction, most commonly seen as necrosis of fingertips. In contrast, these findings and tissue loss are rarely observed in primary RS. A positive serologic screen for rheumatologic conditions in an RS patient is highly predictive of the development of a collagen vascular disease. Evidence of arterial obstruction on vascular laboratory testing also predicts digital ulceration in these patients. Secondary RS as a result of other causes, such as hypercoagulable and hyperviscosity states, lead to tissue loss less commonly.
Testing
Diagnostic modalities include Doppler imaging, nailfold capillaroscopy, thermography, thermal imaging, and digital blood pressures. Most methods to measure temperature or pressures in the digits with cooling require special equipment and do not reproducibly evoke vasospasm. Methods include photoplethysmography before and after cooling of the extremity, with recordings of analogue waveforms from the distal finger pulp along with blood pressure measurement in the index, long, and ring fingers using small pneumatic cuffs. Other methods include thermal entrainment, finger pulse volumes, and Doppler waveform measurement. These methods are more often used in the research setting and are not available to many clinicians. In routine practice, it is typically not recommended to attempt to induce an episode of RS with cold water challenge or other provocative maneuvers because responses may be inconsistent. Specialized vascular laboratories may be able to carry out such testing.
Arteriography is usually not undertaken in the evaluation of RS. In patients with tissue loss or ongoing ischemia or gangrene, arterial angiography is indicated to evaluate for large-vessel disease.
Nailfold Capillary Microscopy
Nailfold capillary microscopy may be performed during a routine office visit by examining the nailfold with an opthalmoscope (with a diopter setting of 40) or with a dissecting microscope. Oil is dropped on the periungual area to assist with visualization of the capillaries. A normal examination reveals regularly spaced hairpin capillaries aligned in the direction of the axis of the finger. The finding of distorted loops or decreased density of capillary loops is abnormal and suggests possible underlying collagen vascular disease. A loss of capillaries is particularly prominent in systemic sclerosis (Figure 2).
Diseases and Factors Associated with Raynaud’s Syndrome
Rheumatologic Diseases
Systemic sclerosis spectrum (scleroderma)
Systemic lupus erythematosus
Dermatomyositis or polymyositis
Rheumatoid arthritis
Takayasu arthritis
Giant cell arthritis
Thromboangiitis obliterans (Buerger’s disease)
Primary biliary cirrhosis
Mechanical Injury
Vibration (hand–arm vibration syndrome)
Frostbite
Recurrent Trauma or Injury to Large Vessels
Crutch pressure
Thoracic outlet syndrome
Arterial Diseases
Brachiocephalic atherosclerosis
Vasospastic Disorders
Migraine or vascular headaches
Prinzmetal’s angina
Endocrine Disorders
Carcinoid syndrome
Pheochromocytoma
Hypothyroidism
Malignant Diseases
Ovarian carcinoma
Angiocentric lymphoma
Hematologic Disorders
Cryoglobulins
Cryofibrinogenemia
Cold agglutinins
Paraproteinemia
Polycythemia
Infections
Parvovirus B19
Helicobacter pylori
Chemicals or Drugs
Bleomycin
Vinblastine
Polyvinyl chloride
β-Blockers
Ergots
Methysergide
Interferon alfa
Interferon beta
Tegafur
