Aneurysm, Thrombosis, and Embolism in Radial, Ulnar, and Digital Arteries

Through the continuation of the radial artery into the hand as the deep palmar arch and the ulnar artery as the superficial palmar arch, circulation to the hand usually is sufficient to allow the digits to remain viable despite most disease and injury. The superficial arch is complete in almost 80% of hands and incomplete in about 20%. The deep arch is complete in about 98% of hands. The radial artery usually provides most of the flow to three or more digits in 57% of hands, whereas the ulnar artery provides flow to three or more digits in almost 22%. Flow provided from both arteries equally is provided in almost 22%.

Ischemic problems in the hand can result from an aneurysm, thrombosis, or embolism in the radial, ulnar, or digital arteries. Arterial occlusive ischemia is associated with trauma from direct blows, instrumentation of the vascular tree for angiography, vascular access procedures, and systemic illnesses, such as atherosclerosis and various collagen vascular diseases.

Symptoms of ischemia, pain, sensory changes, skin discoloration, ulceration, and necrosis can be aggravated by smoking, activity, and exposure to cold. Physical findings include hand or digital pallor or cyanosis, skin ulceration, necrosis distal to areas of occlusion, sensory and possibly motor changes of affected nerves, coolness to palpation, tenderness over an aneurysmal or thrombotic mass, a palpable thrill through an aneurysm, and lack of flow through the affected artery, which is shown by the Allen test (Figs. 70-1 and 70-2). Because of spasms in the distal vessels, this condition can be confused with other conditions, such as Raynaud disease. Plain radiographs, Doppler flow assessment, ultrasonography, pulse volume recordings, segmental arterial measurement, skin temperature measurement, radionuclide scanning, magnetic resonance angiography, and contrast angiography are helpful diagnostic measures. Angiography provides definitive information about the location and extent of the principal lesion and the presence of other circulatory problems in the upper extremity.

FIGURE 70-1 Allen test for patency of radial and ulnar arteries. A, Patient elevates hand and makes fist while examiner occludes radial and ulnar arteries. B, Patient extends fingers, and blanching of hand is seen. C, Radial artery alone is released, and color of hand returns to normal. D, In thrombosis of ulnar artery, test is positive (hand remains blanched) when this artery alone is released.

FIGURE 70-2 Allen test applied to digital arteries. A, Examiner occludes both digital arteries, and patient flexes finger. B, Patient extends finger, and blanching of finger is seen. C, When either artery is patent and it alone is released, color of finger returns to normal. D, When either artery is thrombosed and it alone is released, finger remains blanched.

(From Ashbell TS, Kutz JE, Kleinert HE: The digital Allen test, Plast Reconstr Surg 39:311, 1967.)

Although aneurysms may have atherosclerotic, mycotic, metabolic, and congenital origins, aneurysms seen in the hand and wrist usually are the result of trauma. Blunt trauma can cause true and false aneurysms (see Fig. 76-12), whereas penetrating trauma usually causes false aneurysms to form. Preoperative and intraoperative evaluations of the anatomy of the palmar vascular arch and of the quality of distal circulation are important when deciding between aneurysm excision alone and aneurysm excision with end-to-end repair and reversed vein graft arterial reconstruction. If the palmar arterial arch is complete, and distal circulation is adequate, as determined by pink distal skin color after release of the tourniquet or by pulse volume recordings showing a digital-brachial index of more than 0.7, repair or reconstruction usually is unnecessary. Conversely, if the palmar arterial arch is incomplete, or if the distal circulation is inadequate, the artery should be repaired or reconstructed with a reversed segmental vein graft (Fig. 70-3).

FIGURE 70-3 Resection of thrombosed segment and replacement with reversed vein graft.

(Redrawn from Koman LA, Urbaniak JR: Thrombosis of ulnar artery at the wrist. In American Academy of Orthopaedic Surgeons: Symposium on microsurgery: practical use in orthopaedics, St. Louis, 1979, Mosby.)

Although usually related to occupational or recreational trauma, arterial thrombosis in the wrist, palm, and fingers also can result from arterial cannulation in the forearm. The ulnar artery is the vessel most commonly affected by trauma-related thrombosis, probably because of a relative lack of protection at the wrist and its exposure to repeated forceful impacts, such as when the ulnar side of the wrist is used as a hammer. Sometimes the pain is severe, and sensibility is lost over the distribution of the ulnar nerve in the hand. Tenderness is present over the artery, and occasionally a feeling of fullness is described in the wrist and hand. Although the Allen test (see Figs. 70-1 and 70-2) is helpful in diagnosing thrombosis, arteriography is diagnostic.

Treatment options include exploration of the artery and resection of the entire thrombotic mass, arterial reconstruction with artery or vein grafts, local and regional sympathectomy, and palliation with medical and psychological methods. The history, physical examination, and Allen test determine the initial diagnosis. If the Allen test is positive, thermography, temperature probes, Doppler studies, and pulse volume recordings are used to confirm the diagnosis. If a stellate ganglion or brachial block relieves symptoms, treatment is observation. A stellate or brachial block may relieve vasospasm in acute thrombosis threatening digital survival. If symptoms are not relieved, arteriography is done, and, at the same time, intraarterial medications (reserpine or tolazoline) usually are given. Arteriography establishes the diagnosis, identifies the extent of the thrombosis and vascular disease, and determines the probable success of surgery. Symptomatic treatment is indicated if vascular disease is generalized. If symptoms diminish after arteriography, the patient can be observed. Surgery is indicated if symptoms persist and if digital survival is in question. After the thrombosed segment has been resected, the proximal end is clamped and the tourniquet is released. If backflow is good and pulse volume recordings of the ulnar digits are normal, the vessel is ligated, and the wound is closed. If backflow is poor, with no pulsatile flow on digital plethysmography, vein grafting should be considered. Contraindications to vein grafting include erythrocytosis, patient refusal to modify the environment, and patient refusal to discontinue smoking. If vein grafting is indicated, the entire thrombosed segment should be resected until normal intima is seen with the operating microscope. A reversed vein graft harvested from the forearm is inserted (see Fig. 70-3). Vein grafting is contraindicated if there is inadequate peripheral “runoff” on the arteriogram. Persistent symptoms after surgery can be controlled conservatively by cessation of smoking, biofeedback techniques, and intermittent administration of intraarterial medications; sympathectomy can be used as a last resort.

The thrombosed mass may extend proximally in the forearm but rarely distally across the palmar arch to involve the more distal vessels; in the latter instance, complete resection may be impossible. Adequate resection relieves the spasm of the distal vessels, and symptoms usually improve; the circulation in the hand depends entirely on the radial artery, which usually is sufficient.

In rare cases, thrombosis of a patent median artery may cause pain of median nerve compression within the carpal tunnel. It should be considered in the diagnosis when acute pain in the hand is limited to the distribution of the median nerve.

Arterial lacerations in the wrist and hand are discussed in Chapters 63 and 65. Arterial emboli in the upper extremity account for 15% to 20% of all emboli. About 70% of emboli in the upper extremity are believed to be of cardiac origin (e.g., through atrial fibrillation or as post–myocardial infarction mural thrombi); the remainder are related to the subclavian artery. Usually, acute arterial embolism is signaled by pallor, cold sensation, ischemic pain, paresthesia, occasional paralysis, and loss of palpable or Doppler-sensed pulses. Treatment includes intravenous administration of heparin, Fogarty catheter embolectomy, and warfarin (Coumadin) therapy. If the embolus significantly obstructs flow and cannot be removed, intraarterial administration of streptokinase has been effective if given within 36 hours of thrombosis and if not contraindicated. Newer thrombolytic agents, such as reteplase, may prove effective in the management of this problem.

Thermal Burns

Evaluation of patients with multiple burns proceeds as for patients with multiple acute injuries (see Chapter 65). Life-threatening injuries and extensive body burns take precedence over hand burns. Assessment for inhalation injury is essential because mortality from burns with associated inhalation injury approaches 35%, whereas mortality from burns without inhalation injury is only approximately 2%. Other measures essential to early management include taking appropriate radiographs, establishing intravenous lines, administering tetanus prophylaxis and antibiotics, preparing for blood transfusion, and conducting a careful physical examination. Preserving viable tissue, preventing infection, controlling fibrosis, and avoiding deforming contractures also take high priority in the management of a burn injury in the hand.

Although the initial examination may be difficult because of pain and other injuries, an estimation of burn depth is necessary (i.e., superficial, deep, full thickness, joint or tendon involvement) (Fig. 70-4). The judgment of the treating surgeon usually determines the estimation of burn depth. Other methods used for determination of burn depth range from wound biopsy to MRI. Although most techniques have limitations, noncontact laser Doppler imaging was found to be an accurate method to predict burn depth. Superficial burns (first degree) produce no blisters; although they are erythematous, capillary refill is good, sensation is intact, and the dermis is unharmed. Partial-thickness burns (second degree) are subdivided, depending on the extent of dermal injury, into superficial and deep. In superficial partial-thickness burns, some of the dermis is left intact, blisters may form, and capillary refill and sensation usually are present. Deep partial-thickness burns usually involve the entire dermis. Capillary refill may not be present, sensation usually is not intact, and thrombosed veins may be seen. In deep burns (third and fourth degree) with dermal and subcutaneous necrosis, the skin appears leathery, brown to black, and no circulation or sensation to the skin is present. The most important determination is the adequacy of distal circulation, especially if the burn has a circumferential component.

FIGURE 70-4 Classification of burns by anatomical depth.

(From Baux S: Thermal and chemical burns. In Tubiana R, editor: The hand, vol 3, Philadelphia, 1988, Saunders.)

Circulation of the upper extremity is considered adequate if the hand and fingers have rapid capillary refill and are pink, warm, and soft, and if pulsatile flow can be shown in the palmar and digital vessels with a Doppler probe. If the burn has a circumferential component with decreased distal perfusion (pale hand and fingers; decreased capillary refill; firm, cool hand and fingers; diminished flow shown by Doppler probe), immediate escharotomy should be considered. Intracompartmental pressures also should be measured, and if these are elevated, fasciotomies may be required. While perfusion is being assessed, the patient should receive adequate hydration with appropriate intravenous fluid replacement and monitoring of urinary output.

The depth of the burn, infection, and early management are major determinants of the functional and cosmetic outcome of hand burns. Other important factors are the location of the burn, the patient’s age, and the patient’s compliance with a rehabilitation program. There is agreement regarding the management of superficial hand burns and full-thickness and deeper burns. Superficial burns, if protected from additional injury and infection, should heal within 14 to 21 days with no significant impairment of hand function or cosmesis. Outpatient treatment usually is appropriate for these injuries. For partial-thickness burns (deep dermal, superficial full thickness), two approaches are advocated: (1) a “wait-and-see” method, with conservative treatment consisting of hydrotherapy, topical chemotherapy, and physiotherapy, and (2) an “operative” approach (in the first 3 to 5 days, as soon as practical), with tangential or full-thickness burn excision and early skin grafting (Fig. 70-5). Advocates of conservative treatment believe that with close follow-up and good patient cooperation patients who are treated with topical antimicrobials (silver nitrate, silver sulfadiazine, mafenide acetate, povidone-iodine), hydrotherapy, and an organized rehabilitation program may achieve long-term functional and cosmetic results similar to patients who undergo early surgical treatment. The risks and discomfort of the surgical route are avoided. Falcone and Edstrom proposed an algorithm for management of hand burns that allows flexibility for appropriate, timely treatment, depending on burn depth and apparent wound healing (Fig. 70-6).

FIGURE 70-5 A, Biobrane glove fitted to superficially burned hand. B-D, Excellent cosmetic and functional result after spontaneous healing.

(From Germann G, Weigel G: The burned hand. In Wolfe SW, editor: Green’s operative hand surgery, ed 6, Philadelphia, 2011, Elsevier.)

FIGURE 70-6 Algorithm for treatment of burned hand. TBSA, Total body surface area; PCN, penicillin; CIRC, circulation; ROM, range of motion; CPM, continuous passive motion.

(From Falcone PA, Edstrom LE: Decision making in the acute thermal hand burn: an algorithm for treatment, Hand Clin 6:233, 1990.)

Proponents of surgical treatment of partial-thickness hand burns cite as advantages (1) accurate determination of burn depth early in treatment; (2) earlier physiological healing achieved by definitive débridement, closure, and skin grafting; (3) early and quicker rehabilitation; and (4) avoidance of excessive scarring and contractures associated with the “failed” conservative method. Tangential excision with skin grafting and full-thickness excision with skin grafting are two techniques used for treatment of partial-thickness hand burns. The advent of vacuum-assisted closure (VAC), with and without the use of skin substitutes, has made early surgical intervention a better choice.

The special characteristics of the soft tissues in the hand allow for what might be considered a combined approach to partial-thickness burns of the hand. Dorsal burns may benefit from early excision (within 14 days) allowing for protective coverage and early mobilization of the superficial extensor tendon mechanism and interphalangeal joints where extension contractures can be devastating to hand function. On the flexor surface, the flexor mechanism and joints are deeper and relatively better protected and may tolerate a delay of 3 weeks better than the dorsal structures.

For deep full-thickness burns (third and fourth degree), primary full-thickness excision of the burn wound with skin grafting is the appropriate treatment (Fig. 70-7). When tendons, nerves, vessels, ligaments, bones, and joints are damaged by thermal injury, measures in addition to burn wound excision and split skin grafting may be required. Stabilization of bones and joints with Kirschner wires, arthrodesis of destroyed joints, local and remote pedicled skin flaps, and free tissue transfers may be needed to preserve a viable, functioning hand. (For additional information, see Chapter 67 for fractures, Chapter 73 for arthrodesis, Chapter 65 for flaps, and Chapter 63 for microvascular flaps.)

FIGURE 70-7 A, Tangential excision of deep partial-thickness burn on dorsum of hand. B, Sheet graft transplantation to excised areas. C, Short-term postoperative result.

(From Germann G, Weigel G: The burned hand. In Wolfe SW, editor: Green’s operative hand surgery, ed 6, Philadelphia, 2011, Elsevier.)

The inelastic nature of full-thickness, circumferentially burned skin creates a tourniquet effect as edema increases in the burned extremity. Perfusion to subcutaneous structures may be diminished by the increase in pressure. Incision through the eschar (escharotomy) helps to relieve pressure and preserve threatened tissues. Compartment syndromes that develop after deep burns may be prevented with fasciotomy.

An organized plan of rehabilitation is important to the success of the treatment of the burned hand. The focus of rehabilitation in the early acute stage is wound care, edema control, and preservation of motion. After closure of the burn wound, a program including static and dynamic splinting, active and passive range-of-motion exercises, and control of scar and edema is pursued. The rehabilitation plan depends on the needs of the individual patient and requires the participation of hand therapists, occupational and physical therapists, and physical medicine consultants. Many patients with severe and disfiguring burns require the emotional support of psychiatric and psychological consultants.

Electrical Burns

Electrical burns frequently involve the upper extremity. The dominant hand frequently is injured, and 50% of these injuries result in amputation. Tissue damage can result from a combination of thermal, electrical, and metabolic cellular factors. The extent of injury is determined by the characteristics of the injuring current, including the voltage, amperage, and resistance of the tissues; the duration of contact with the current; and the patient’s susceptibility to it (Fig. 70-8). Although the skin damage caused by electrical injury may be the most impressive presenting finding, significant deep injury may be present as determined by the route the electrical current takes through the body. Electrical injuries may involve the central and peripheral nervous systems, the cardiopulmonary and peripheral vasculature, the musculoskeletal system, the kidneys, and the skin. Initial management is directed at resuscitation. Appropriate diagnostic measures include radiographs of potential fractures and dislocations; electrocardiogram; and serum chemistries to assess electrolytes and liver, renal, cardiac, and skeletal muscle injury. Urine myoglobin levels and arterial blood gases are measured as well. The extent of injury to all systems should be evaluated, ensuring satisfactory hydration and urinary output, because patients with electrical burns may require more fluid resuscitation than might be calculated based on the injury to the total body surface area. Urinary output of 50 to 100 mL/hr is preferable. Recognizing, stabilizing, and reversing the effects of cardiac injury and the nephrotoxic effects of myoglobinuria and hemoglobinuria also are important. Because of the potential for hemorrhage from damaged vessels, a tourniquet should be kept near the patient’s bedside.

FIGURE 70-8 Electrical contact. Various damaging forces involved in high-energy electrical shock. With voltages greater than 1000 volts, electrical contact (arc mediated) precedes mechanical contact. High surface temperatures at contact points produce deep burns. Current passage through extremity leads to electrical breakdown of muscle and nerve membranes. Prolonged contacts of several seconds result in substantial deep tissue burning. High-energy arcs produce shock waves that can cause blunt trauma.

(From Danielson JR, Capelli-Schellpfeffer M, Lee RC: Upper extremity electrical injury, Hand Clin 16:225, 2000.)

In electrical burns of the hand and upper extremity, the initial evaluation should include a thorough examination of the entire body for skin and neuromuscular injury. Evaluation of circulation includes examination of skin color and warmth, palpation of peripheral pulses, and flow assessment with a Doppler probe. Skin burns may be the result of contact, flame, flash, or electrical arcing, or all of these may be factors. Contact burns have a central charred area surrounded by erythema. Flash and flame burns are thermal injuries, having the appearance of other thermal burns. Arcing burns usually are seen in the axilla, the antecubital fossa, and the distal forearm. There is no correlation between the size of the skin injury and the actual extent of injury.