Acknowledgment:
This chapter was previously written by Dr. Andrew Koman and his associates. The author acknowledges Dr. Koman’s scientific approach to the subject and his lifelong body of research into ischemia of the hand. The reader is referred to the chapter in the previous edition if a more scientific background on ischemia of the hand is desired.
Vascular disorders of the hand are relatively uncommon but can pose significant problems for patients suffering from them. Ischemic pain, ulceration, and decreasing hand function because of the foregoing are just some of the problems they face. Proper management of patients can improve their quality of life dramatically and on occasion prevent loss of tissue and potentially even the limb.
Anatomy
Arterial blood is supplied to the hand through the brachial artery that branches in the proximal forearm primarily into the radial and ulnar arteries. These two major vessels continue down the forearm and supply the major portion of the blood that flows into the hand. The anterior and posterior interosseous vessels can provide flow via collateral circulation in chronic vascular problems; however, these two vessels are much smaller and generally cannot provide adequate oxygenated blood in the case of acute injury to both the radial and ulnar vessels. More recent work has determined that the volar forearm’s median artery can provide significant blood flow to the hand, particularly in the case of injury or harvest of the radial artery.
Blood supply to the hand was first clearly elucidated by Coleman and Anson in their classic paper, in which they found that most hands have both a “superficial” and a “deep” arch that supplies the fingers. They found that 78% of the hands studied had a “complete” superficial arch, which theoretically allowed normal flow to all the fingers passing through the arch if flow by means of the radial or ulnar arteries was compromised. The ulnar artery flows into the hand on the palmar surface; its terminal portion becomes the superficial arch, while the radial artery courses around the radial volar wrist into the anatomic snuffbox, then it enters the palm via the first webspace. The terminal branches of the radial artery turn into the princeps pollicis and the deep palmar arch ( Figure 60.1 ).
Much has been made of the presence or absence of a complete arch over the years; however, a great deal of clinical experience has shown that acute interruption of flow in either the radial or ulnar artery is extremely unlikely to result in significant ischemia of the hand or fingers. In terms of which vessel provides the dominant circulation to the hand, the results of studies have been variable, with most finding that the ulnar artery is dominant and others finding that it is the radial. I would think that this point is actually moot because injury to one of the two vessels alone rarely causes any ischemia of the hand.
While the arterial supply to the hand enters primarily on the palmar surface, most of the venous drainage begins on the dorsal fingers and continues on the hand’s dorsal surface. The primary arteries of the hand are each followed by two small venae comitantes, the configuration of which actually continues out to the fingers into the digital arteries. The primary drainage of the hand is, however, via the dorsal system, which eventually drains into the cephalic and basilic veins on the forearm and upper arm. Problems with venous drainage of the hand are extremely unusual—with the exception of possible venous thrombosis after replantation—due to the many venous channels available.
Etiology of Ischemia
Hand ischemia can result from iatrogenic injury, trauma, or vascular disease. Fortunately, iatrogenic injury is unusual; however, the potential to negatively affect flow to the hand is present in many procedures. An Allen’s test should be performed routinely prior to any intervention involving the radial artery ( Figure 60.2 ). Radial artery puncture is a commonly used procedure for harvesting blood to measure gases, and indwelling catheters in the radial artery are commonplace for the monitoring of unstable patients during and after surgery. Although isolated radial artery puncture is exceedingly unlikely to cause ischemia in the hand, indwelling catheters are known to cause permanent ischemic complications in approximately 0.09% of patients.
In the group of patients who develop ischemic problems, studies have shown that surgical intervention is not universally successful, probably due to the severity of vascular disease in the radial artery and the effects of distal embolization from the site of injury ( Figure 60.3 ). Depending on the patients’ underlying problems, it may be best to manage them with anticoagulation, regional nerve blocks, and possibly intraarterial thrombolytics. The increasing trend toward management of vascular problems with endovascular techniques has led to renewed interest in peripheral artery access, with the radial artery offering a relatively easy way into the arterial system. While early reports minimize the complications of this approach, it remains to be seen whether increasing application of this technique will lead to more ischemic problems in the hand.
Currently, the radial artery is often harvested for cardiac revascularization and radial forearm flap reconstruction, which also can lead to hand ischemia. The standard to use to avoid problems is the preoperative Allen’s test, as noted earlier. Despite the routine use of it, ischemic episodes have been reported after radial artery harvest. This problem can be managed successfully, however, by performing a bypass with the autologous vein to replace the harvested radial artery.
Another iatrogenic cause of ischemia is vascular access in the upper extremity for hemodialysis. This happens in a range of 2 to 5% after a vascular access procedure and can be due to distal embolization or a “steal” phenomenon; in this case, the majority of the arterial flow is diverted across the fistula, leading to ischemia in the distal hand. Often the fistula will have to be banded or even ligated to decrease the shunting of blood from the hand; however, vascular surgeons are usually unwilling to ligate these because of the difficulties of long-term access in dialysis patients. Another option is the so-called “distal revascularization interval ligation,” or DRIL, procedure.
In this operation, a vein graft is sewn into the artery above the site of the fistula and the bypass is anastomosed to the distal artery at a level beyond it. The native artery is then ligated just distal to the fistula. This theoretically leads to the hand getting the majority of flow rather than the shunt and is effective in many patients. Diabetic patients on dialysis present other difficulties in that they often develop worsening arteriosclerosis of the upper extremity’s vessels and ongoing ischemia; this will be discussed further later.
The other cause of ischemia of the hand is trauma, which can be either an open or a closed injury to forearm and hand vessels. The classic case of a closed injury to the hand’s arterial supply is in supracondylar fractures in children. In these patients, displacement of the fracture leads to injury and spasm of the brachial artery, which if not recognized can lead to a compartment syndrome and ultimately a Volkmann ischemic contracture of the flexor muscles. Another fairly common type of closed vascular injury unique to the hand is ulnar artery thrombosis, or “hypothenar hammer syndrome.” This injury occurs with closed trauma to the palm of the hand, often when it is used as a hammer or when the hypothenar area suffers a blow. Open injuries, whether by firearms or by lacerations, are particularly common in the forearm and hand. As noted earlier, injury to a single vessel rarely causes acute ischemia but undiagnosed injuries can lead to aneurysm formation and potential distal embolization.
The final cause of ischemia in the hand is intrinsic vascular disease, which can be either arteriosclerotic or vasospastic. They can be seen in combination, which is known as “vasoocclusive” disease. Although Buerger disease has historically been a major cause of arteriosclerotic disease in the upper extremity, in today’s world the most common cause is a combination of diabetes and renal insufficiency. This combination of disease processes leads to accelerated occlusive vascular disease in the upper and lower extremities, and it is not uncommon to see patients with bilateral lower-limb amputations appear with critical ischemia of the hand. Likewise, patients with collagen vascular disease (i.e., scleroderma primarily) suffer from vasculitis and vasospastic disease, which can lead to vasoocclusive disease. The patients can present difficult management issues, and surgical intervention, while helpful, often does not provide a long-term solution.
Evaluation
As with any problem, patients first need to provide a thorough history and undergo a physical examination. Obtaining a medical history, with particular attention to documented diabetes and/or collagen vascular disease, is very important. Obviously, a habit of smoking will have an impact as well. Medical management of the diseases with pharmacologic agents may mitigate some of the symptoms, particularly in those patients with Raynaud disease. The physical exam should pay close attention to the appearance of the hands and the color of the fingers, looking for evidence of ischemia and/or gangrene or ulceration. Likewise, the warmth of the fingers is important and sensation also plays a role, with the potential for sympathetic overactivity in the presence of nerve compression.
The pulses at the elbow and wrist should be felt, and I feel that Doppler ultrasound plays a very important role in the examination of the patient with a vascular disorder. An Allen’s test can be done, as described before; however, performing a similar exam with the pencil Doppler may yield much more information. The arch is located with the Doppler, and the radial and ulnar arteries are compressed sequentially at the wrist. The Doppler can be moved over the arch as necessary to follow the signal, listening for a change in character or flow. This technique can almost always diagnose the site of arterial occlusion if performed carefully. Likewise, an arterial signal should be heard with the Doppler placed on the pulp of the finger; if it is not, there is a significant problem with flow to that finger.
It should be noted, however, that the presence of an audible Doppler arterial signal in one of the wrist’s vessels is not an indication of adequate nutritional flow to the hand. By using this simple technique in the office the surgeon usually can diagnose where the occlusion is; however, this information is not adequate for planning a surgical procedure. For this I prefer using computerized tomographic angiography (CTA) or arteriography—the latter if fine detail of the hand’s vessels is needed ( Figure 60.4 ).
Others prefer a magnetic resonance angiography (MRA), but I have found that the detail in many of these images is inadequate in terms of knowing exactly where and how significant the problem is. The gold standard, however, remains digital subtraction angiography (DSA). Surgeons must view the vascular studies themselves because the radiologist or vascular specialist may or may not see the lesion. A familiarity with the upper extremity’s normal and variant anatomy is essential; however, surgeons who are dealing with vascular problems must evaluate every vascular study, both to review the anatomy and to identify the problem ( Figure 60.5 ).
There are a number of other types of studies that can be done to aid in the diagnosis of vascular problems in the hand. Color-flow ultrasonography can show realtime flow and be used to evaluate an anastomosis, but it is of primary use in the venous system. A commonly performed test to evaluate vasospasm is cold-stress testing, which gives a measure of the vascular system’s ability to recover from exposure to cold. In this test digital temperature is measured at baseline and the hand is then placed in cold water (5–8°C) for 5 minutes. Thermistor probes (or laser Doppler) are used to measure the time required for digital rewarming to baseline. A prolonged rewarming response is often seen in women and can be diagnostic of Raynaud’s. Likewise, smokers often have a delayed rewarming response.
The digital–brachial index, which is the ratio of the blood pressure as measured in the brachial artery and the finger, can be measured with small blood pressure cuffs. This is similar to the ankle–brachial index, and in the upper extremity any value below 0.7 is felt to designate a significant occlusive problem somewhere in the forearm or hand. Blood flow in the capillary bed can be measured by laser Doppler flowmetry, which can give a quantitative measurement of blood flow at skin level. This can be a useful tool to evaluate the results of treatments, particularly for vasospastic problems; however, this equipment is quite expensive and not available to most practitioners.
Similarly, nailfold capillaroscopy shows morphology and flow at the capillary level but is not of practical use for most surgeons. Many of these sophisticated tests are difficult for the practicing surgeon to perform and do not add much, in my opinion, to decision making in terms of patient management. They, however, can be useful in determining the quality of the outcomes of management. The chapter on vascular problems in prior editions of this textbook (i.e., Chapter 66) has a more thorough and excellent discussion of these modalities and the reader is referred to the earlier edition for more information on this subject.
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Hunter (1704): Ligation of the artery proximal to an aneurysm (popliteal); described traumatic aneurysm
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Raynaud (1862): Described syndrome of peripheral vasospasm
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Mata (1888): Endoaneurysmorrhaphy
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Carrell (1902): Described technique of end-to-end anastomosis of blood vessels
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Murphy (1905): Resection of cervical ribs causing impingement on the brachial artery
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Leriche (1937): Sympathectomy as an effect of excision and ligation of an artery
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Korean conflict (1952): Demonstration of successful arterial repair
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Allen (1962): Description of Allen’s test
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Kleinert (1965): Revascularization of the superficial palmar arch
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Flatt (1980): Periarterial digital artery sympathectomy
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Koman (1995): Palmar and wrist sympathectomy for secondary Raynaud’s phenomenon
Evaluation
As with any problem, patients first need to provide a thorough history and undergo a physical examination. Obtaining a medical history, with particular attention to documented diabetes and/or collagen vascular disease, is very important. Obviously, a habit of smoking will have an impact as well. Medical management of the diseases with pharmacologic agents may mitigate some of the symptoms, particularly in those patients with Raynaud disease. The physical exam should pay close attention to the appearance of the hands and the color of the fingers, looking for evidence of ischemia and/or gangrene or ulceration. Likewise, the warmth of the fingers is important and sensation also plays a role, with the potential for sympathetic overactivity in the presence of nerve compression.
The pulses at the elbow and wrist should be felt, and I feel that Doppler ultrasound plays a very important role in the examination of the patient with a vascular disorder. An Allen’s test can be done, as described before; however, performing a similar exam with the pencil Doppler may yield much more information. The arch is located with the Doppler, and the radial and ulnar arteries are compressed sequentially at the wrist. The Doppler can be moved over the arch as necessary to follow the signal, listening for a change in character or flow. This technique can almost always diagnose the site of arterial occlusion if performed carefully. Likewise, an arterial signal should be heard with the Doppler placed on the pulp of the finger; if it is not, there is a significant problem with flow to that finger.
It should be noted, however, that the presence of an audible Doppler arterial signal in one of the wrist’s vessels is not an indication of adequate nutritional flow to the hand. By using this simple technique in the office the surgeon usually can diagnose where the occlusion is; however, this information is not adequate for planning a surgical procedure. For this I prefer using computerized tomographic angiography (CTA) or arteriography—the latter if fine detail of the hand’s vessels is needed ( Figure 60.4 ).
Others prefer a magnetic resonance angiography (MRA), but I have found that the detail in many of these images is inadequate in terms of knowing exactly where and how significant the problem is. The gold standard, however, remains digital subtraction angiography (DSA). Surgeons must view the vascular studies themselves because the radiologist or vascular specialist may or may not see the lesion. A familiarity with the upper extremity’s normal and variant anatomy is essential; however, surgeons who are dealing with vascular problems must evaluate every vascular study, both to review the anatomy and to identify the problem ( Figure 60.5 ).
There are a number of other types of studies that can be done to aid in the diagnosis of vascular problems in the hand. Color-flow ultrasonography can show realtime flow and be used to evaluate an anastomosis, but it is of primary use in the venous system. A commonly performed test to evaluate vasospasm is cold-stress testing, which gives a measure of the vascular system’s ability to recover from exposure to cold. In this test digital temperature is measured at baseline and the hand is then placed in cold water (5–8°C) for 5 minutes. Thermistor probes (or laser Doppler) are used to measure the time required for digital rewarming to baseline. A prolonged rewarming response is often seen in women and can be diagnostic of Raynaud’s. Likewise, smokers often have a delayed rewarming response.
The digital–brachial index, which is the ratio of the blood pressure as measured in the brachial artery and the finger, can be measured with small blood pressure cuffs. This is similar to the ankle–brachial index, and in the upper extremity any value below 0.7 is felt to designate a significant occlusive problem somewhere in the forearm or hand. Blood flow in the capillary bed can be measured by laser Doppler flowmetry, which can give a quantitative measurement of blood flow at skin level. This can be a useful tool to evaluate the results of treatments, particularly for vasospastic problems; however, this equipment is quite expensive and not available to most practitioners.
Similarly, nailfold capillaroscopy shows morphology and flow at the capillary level but is not of practical use for most surgeons. Many of these sophisticated tests are difficult for the practicing surgeon to perform and do not add much, in my opinion, to decision making in terms of patient management. They, however, can be useful in determining the quality of the outcomes of management. The chapter on vascular problems in prior editions of this textbook (i.e., Chapter 66) has a more thorough and excellent discussion of these modalities and the reader is referred to the earlier edition for more information on this subject.
- •
Hunter (1704): Ligation of the artery proximal to an aneurysm (popliteal); described traumatic aneurysm
- •
Raynaud (1862): Described syndrome of peripheral vasospasm
- •
Mata (1888): Endoaneurysmorrhaphy
- •
Carrell (1902): Described technique of end-to-end anastomosis of blood vessels
- •
Murphy (1905): Resection of cervical ribs causing impingement on the brachial artery
- •
Leriche (1937): Sympathectomy as an effect of excision and ligation of an artery
- •
Korean conflict (1952): Demonstration of successful arterial repair
- •
Allen (1962): Description of Allen’s test
- •
Kleinert (1965): Revascularization of the superficial palmar arch
- •
Flatt (1980): Periarterial digital artery sympathectomy
- •
Koman (1995): Palmar and wrist sympathectomy for secondary Raynaud’s phenomenon
Management
Management of vascular injury or insufficiency in the hand may involve techniques ranging from ligation of the injured vessel to periarterial sympathectomy to complex vein or arterial grafting. Which technique is employed depends on the level of the lesion as well as the cause of the problem. The various techniques used to treat the major causes of ischemia of the hand are discussed in the following subsections.
Open Arterial Trauma
Arterial trauma is reasonably common in the upper extremity and can be due to laceration or closed injury, as noted earlier. Reviews have noted that the majority of these injuries are open (i.e., in the 79% range) and that most were the result of lacerations. The options for management differ somewhat and are discussed here. Open arterial trauma generally requires exploration because there is a wound that needs to be managed, and likewise, injuries to other structures almost always will require repair.
In general, preoperative workup of patients with an open vascular injury is limited to physical examination because a high index of suspicion should be present based on the history and location of the injury. Arterial studies are generally not indicated in open injuries with the exception of gunshot wounds with an otherwise normal examination of motor and sensory systems. It should be noted, however, that clinical studies have demonstrated that up to 50% of vessels with a proximal injury will have a palpable pulse at the wrist. If the limb is well perfused, delay in management of the injury (i.e., beyond 6 h) if the bleeding is controlled and the patient is hemodynamically stable has not been shown to be detrimental. It also has been shown in the military’s experience during recent conflicts that temporary arterial shunting is a valuable adjunct in the management of arterial injuries. In such patients, shunts were left in as long as 11 hours and in some cases until definitive repair could be performed. The results between patients who had immediate vascular repair and those shunted showed no significant differences in outcomes.
At the time of exploration, the wound will need to be extended in order to allow exploration and repair of the injured structures ( Figure 60.6 ). If the hand is well perfused, a decision needs to be made as to whether repair of the injured vessel is important to the circulation in the hand. The brachial artery can suffer injury from fractures about the elbow, particularly in children with closed supracondylar humeral fractures. Such injuries can lead to significant ischemia of forearm muscles and the hand. Studies have demonstrated that single-vessel (i.e., radial or ulnar artery) injuries in the forearm lead to little long-term sequelae even if the injured vessel is simply ligated.
The flow in the remaining vessel has been shown to increase with injury or ligation of the other, and patency rates of repaired single vessels have been shown to be surprisingly low (i.e., in the 50% range), even with proper technique. Arterial injuries combined with median nerve injuries have been shown to lead to increased long-term problems, probably more related to nerve injury than arterial injury. In younger patients and in those with possible vascular compromise from other factors, repair of the radial or ulnar arteries in the forearm almost certainly should be undertaken.
Author’s Preferred Method of Treatment: Arterial Vascular Repair
Sharp injuries with complete transection will lead to vessel ends pulling apart, depending on local branches and the surrounding tissue. Cutting injuries usually can be pulled together after careful trimming of the ends of the divided vessel. While forearm vessels can be sewn by most competent hand surgeons with loupes, studies have shown that a better anastomosis can be performed with a microscope. If there is some tension, a large double clamp (e.g., an Acland or Ikuta microvascular) can be used to take the tension off the repair. A repair should be done in standard microsurgical fashion, and I prefer 8-0 nylon for forearm vessels, and in some cases use 7-0 polypropylene if the vessel is larger. I always use 6-0 or 7-0 polypropylene for the brachial artery and most proximal vessels. If there is a partial injury, which is sharp, it often can be repaired primarily; however, in some instances damage to the vessel of partial injuries (e.g., gunshot wounds) may well require resection of the injured segment and vein grafting.
When a vein graft is necessary, it is probably best (and easiest) to harvest it from the injured arm ( Figure 60.7 ). Although saphenous is an acceptable choice, I have found that it is rather thick-walled and not always the perfect size match for the radial and ulnar arteries in the forearm. There are several maneuvers that can be performed if the vein graft and artery have a circumference mismatch ( Figure 60.8 ). If a vein graft is going to be done, one must resect an adequate segment of the injured artery to be sure that the anastomosis can be performed out of the zone of injury to decrease the rate of thrombosis. Usually, this is fairly obvious, but any portion of the vessel that has suffered bruising, or has signs of intimal separation when viewed under the microscope, should be resected.
An artery with thrombus in it is not be an absolute indication to resect the vessel, as long as the arterial wall does not appear to have suffered damage. After the end is resected, it is probably wise to irrigate the proximal and distal vessels with heparinized saline (generally diluted to 100 units of heparin per milliliter of saline) to decrease the risk of thrombus formation during the time that the clamp is on the artery. Once this is done, I prefer to perform the proximal anastomosis first. When complete, removing the clamp allows the vein graft to fill with blood and both unwind and return to its normal length. After the proximal clamp is removed, the vein is allowed to bleed briefly from the end and is then reclamped. The proper length can then be better estimated than when the vein is empty.
The distal end is trimmed to the proper length if necessary and the distal anastomosis is then performed ( Figure 60.9 ). Once the anastomosis is completed, distal pulses must be checked. A Doppler can be used, but I feel that a palpable pulse is a much better sign of adequate distal flow. The surgeon should be aware that a clot can propagate distally and embolize into the distal artery or even the hand. Familiarity with the techniques of thrombectomy is essential for those performing vascular repairs (see Figure 60.3 ). Tension on the repair is checked by ranging the wrist and elbow, as disruption of one of the anastomosis with movement of the hand or arm can be catastrophic.
Arterial repairs and arterial vein grafts cannot be left exposed in a wound nor should they be covered just with skin grafts or an allograft. Viable tissue must be placed over repairs to avoid desiccation and disruption of the repair; at times this may necessitate some type of flap. If the wound is large, as in avulsion-type injuries, selection of a vein for grafting may need to incorporate a branch to allow for placement of a free flap over it with arterial anastomosis to the branch of the graft ( Figure 60.10 ).
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Resect wounded artery beyond zone of injury (bruising and/or intimal separation).
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Select appropriate length of forearm vein (i.e., basilic or cephalic), alternatively saphenous.
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Irrigate proximal and distal arteries with heparinized saline.
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Reverse vein graft and repair to proximal artery first, with 7-0 polypropylene or 8-0 nylon.
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Allow vein graft to fill with blood and clamp distally; allows vein to unwind and distend.
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Trim appropriately and perform distal repair.
Postoperative Care After Vein Graft Repair.
I generally splint the elbow and/or wrist after vascular repair or vein grafting in the forearm. If the graft is loose, this is probably not necessary; however, based on the contributing trauma and severity of injury, immobilization is probably prudent. Care must be taken to ensure that the splint does not impinge or put pressure on the graft. Systemic anticoagulation has not been shown to be beneficial and in fact can cause bleeding, so this should be avoided—the patient will have received some systemic heparin from the irrigation of the proximal and distal artery that is probably adequate.
Oral aspirin may have some benefit and should be given in a low dose (i.e., 81 mg) daily for 6 weeks. I allow the patient to begin careful movement after about 3 weeks; however, this depends on which other structures (i.e., bone, tendon, nerve) have been injured and the therapy requirements for them if they have been repaired. Patency rates are generally high in upper extremity vascular repairs done with an autogenous vein.
Complications.
The primary complication of arterial repair and/or forearm grafting is thrombosis of the repair or graft. This is unlikely to occur unless the surgeon has failed to resect the damaged vessel or has performed a poor vascular repair. Blowout of a repaired artery or vein graft is not unheard of, however, and can be a catastrophic event and life threatening (see Figure 60.18 ). There must be coverage of the repaired artery or vein graft with well-vascularized soft tissue. If there is wound breakdown, this must be managed aggressively to prevent infection around the repair or graft as well. “Watchful waiting” is not advisable if there are problems with a repaired vessel.
Closed Arterial Trauma
Although blunt trauma can cause arterial injury anywhere in the upper extremity, the most commonly seen closed trauma is ulnar artery thrombosis in the palm. As noted previously, this is also called hypothenar hammer syndrome; it is seen in patients who suffer trauma to the palm or those who use the ulnar side of the palm as a hammer. Due to its relatively superficial position, the ulnar artery and nerve are easily injured with blunt trauma to the palm ( Figure 60.11 ).
Injuries to the ulnar artery in the Guyon canal can lead to thickening of the vessel wall (with chronic low-grade trauma), disruption of the intima and thrombosis, or even aneurysm formation ( Figure 60.12 ). Regardless of the eventual pathology, these injuries can lead to distal ischemic symptoms, primarily as a result of embolization of thrombus from the site of injury. The incidence of ulnar artery thrombosis is probably underreported; I believe that many individuals may suffer from this and are not particularly symptomatic or fail to seek medical advice due to ongoing excellent perfusion of the hand through the radial artery.
Patients with ulnar artery thrombosis present with ischemic symptoms in the ulnar digits, and in my experience with more than 100 patients with this, the ring finger is involved in nearly half of the patients, with the middle and little fingers involved in closer to one-third ( Figure 60.13 ). The thumb is rarely ischemic in patients with ulnar artery thrombosis. While it has been taught that distal ischemia is due to vasospasm, exploration of a number of these fingers in the past has proven that this is the result of embolization of thrombus ( Figure 60.14 ). These patients frequently complain of paresthesias in the distribution of the ulnar nerve as well because the ulnar nerve can suffer contusion at the time of ulnar artery injury.
Diagnosis usually can be made based on history and physical exam. The patient relates an incident of trauma to the palm with symptoms of digital ischemia of the ring and little finger following, and there may be ulnar nerve paresthesias as noted earlier. These symptoms may resolve but also may be intermittent after the injury (i.e., due to ongoing embolization of a clot to the distal digits). By the time the patient sees a hand surgeon, the initial symptoms may have resolved to some degree but he or she usually complains of cold intolerance and intermittent color change in the fingers. The office exam obviously should include feeling the pulse at the wrist; however, the ulnar pulse may well be present proximal to the wrist crease. There actually may be a palpable mass in the ulnar palm due to either a large amount of clot in the artery or potentially aneurysmal change as a result of the injury.
I perform a “dynamic” exam with a pencil Doppler as described before. Typically, occlusion of the radial artery at the wrist causes loss of signal over the palmar arch. With this history and exam, arterial studies should be the next step. CT arteriogram is usually sufficient to diagnose ulnar artery thrombosis if the CTA’s quality is high; however, if there is any question, a standard arteriogram should be obtained. This is helpful in terms of knowing how far one may need to graft in order to bypass the area of occlusion. Likewise, some patients may develop an aneurysm due to severe intimal injury, which may change treatment options to some degree.
The pattern of thrombosis is fairly typical and can be seen clearly on an arteriogram of the involved hand. While the original injury is in the palm, over time the thrombus usually propagates back to the dorsal branch of the ulnar artery; it occurs roughly 2 to 3 cm proximal to the volar wrist crease. Likewise, the vessel clots distally to the palmar arch, where the common digital artery to the fourth webspace branches. At both of these points there is still outflow (i.e., from the dorsal–ulnar artery proximal and the palmar arch distally); thus, the initial injury leads to propagation of the clot to these branches ( Figure 60.15 ).
If the patient is seen soon after injury, the area of thrombosis may be smaller as a clot has not had time to propagate proximally and distally. Arteriography also may show a “corkscrew” pattern that implies a damaged artery and in fact may show an aneurysm ( Figure 60.16 ). Some patients can damage the artery enough to lead to development of a large aneurysm that may be palpable. Interestingly, these do not always thrombose but can certainly cause recurrent distal embolization of a clot.
Once the patient is evaluated and thrombosis of the ulnar artery is confirmed, the decision as to how to manage him or her must be made. Patients with minimal symptoms, good flow through the radial artery, and an otherwise normal palmar arch, can be managed medically. If the patient is a smoker, cessation of this activity is nearly mandatory to decrease symptoms. Similarly, calcium channel blockers (CCBs) can be used to decrease symptoms of vasospasm brought on by the clot. If the patient is seen early on after the thrombosis, thrombolytic therapy with tissue plasminogen activator can be tried, but success has not been universal in reported cases. Management of ulnar artery thrombosis by endovascular techniques also has been reported ; however, there is no convincing evidence that it is applicable to arteries at the distal forearm level. Patients with aneurysms of the ulnar artery and those who continue to have symptoms will require surgical intervention.
The approach to the ulnar artery via the Guyon canal is standard. A Bruner-type incision is made in the palm over the course of the ulnar artery to the level of the distal palmar crease to allow it to be carried across the palm if necessary. Usually this incision needs to be carried proximally about 3 cm up the distal forearm for access to the ulnar artery at the level of the dorsal branch. While the thrombosed segment of artery can be simply ligated and excised, which accomplishes a “Leriche” sympathectomy, Koman and others have demonstrated that a bypass offers significant improvement over excision.
Author’s Preferred Method of Treatment: Ulnar Artery Bypass
On occasion, the area of thrombosis is small, the involved artery can be resected, and the ulnar artery repaired primarily, but this is unusual. In most cases, a vein graft is required from the distal forearm to the palmar arch where the common digital artery to the fourth webspace branches off. I prefer to utilize the basilic vein in the mid-forearm to graft the ulnar artery in such cases. This vein offers several advantages over the saphenous in that it is locally available, the wall is not as thick as the saphenous, and the donor site rarely has healing problems. There has been some discussion about the use of arterial grafts for the management of ulnar artery thrombosis, the argument being that an arterial graft may withstand future trauma better than a vein graft and the size match of available arteries—that is, primarily the deep inferior epigastric and descending lateral femoral circumflex. Although I have had limited experience with this technique, it would appear to have some merit. The benefits of arterial grafts over standard vein grafts have yet to be proven convincingly, however.
The thrombosed or aneurysmal segment of the ulnar artery is resected back proximally until there is no further thrombus and the intima and medial layers of the vessel wall do not separate when the vessel is cut. The vein is reversed and the technique is as described earlier for traumatic injuries. The distal anastomosis can almost always be performed at the level of the “Y” between the common digital artery to the fourth webspace and the superficial palmar arch ( Figure 60.17 ). Postoperative care is the same as for any venous interposition graft, with attention being paid to avoid kinking of the graft with motion or any pressure on the graft from a splint. I generally do not anticoagulate patients undergoing vein grafting of an ulnar artery thrombosis but give them an 81-mg aspirin daily for at least 6 weeks postoperatively. As noted before, cessation of smoking is essential if ongoing symptoms are to be prevented.
The results of vein grafting of a traumatic ulnar artery thrombosis are generally good, and my experience has been that there is around a 90% patency rate at 2 years. Even patients who suffer another thrombosis of the ulnar artery do not always become symptomatic again, probably because of the sympathectomy effect of resection of the thrombosed ulnar artery.
Complications.
The complications of ulnar artery bypass are the same as those noted after arterial repair or grafting in the forearm. The bypass can thrombose, which can be due to ongoing trauma to the palm, and there is evidence that thrombosis rates of vein grafts increase over time. The rare complication of blowout of the vein graft can be significant but usually is the result of wound-healing problems ( Figure 60.18 ).
The radial artery also can suffer from thrombosis in the hand, and this usually occurs in the anatomic snuffbox over the area of the trapezium (Tq) and under the extensor pollicis longus (EPL). The symptoms of this disorder are primarily ischemia of the index finger and occasionally the thumb. The patient also may complain of dull pain in the thenar muscles, which may be a type of claudication from ischemia of the muscles. The etiology of this is unclear, but it would appear to be from trauma to the artery from the overlying EPL tendon. This problem is more common in women than in men, in my experience, and is not usually seen in those with collagen vascular disease. These patients also suffer from embolization of clot into the distal index finger, and ulnar-sided fingers are basically never involved.
Arteriography may in fact show thrombus in the radial artery in the anatomic snuffbox ( Figure 60.19 ). This problem seems to resolve in some patients without the need for further intervention; however, if the radial artery is found to be completely occluded on arteriogram and the patient is suffering from critical ischemia of the finger, treatment with excision of the clotted segment and vein grafting is probably warranted. The cephalic vein is in the field when the radial artery is exposed, and this can be used for the graft. The issue of the EPL tendon pressing on the graft must be addressed, and while the graft may be brought superficial to it, I will usually make a small sling out of a portion of the extensor carpi radialis longus (ECRL) tendon from the base of the second metacarpal to pull the EPL away from the graft ( Figure 60.20 ). Alternatively, the EPL can be freed from its fascial sling at the Lister tubercle and allowed to slide away from the artery proximally.
Vascular Disease
Arterial occlusive disease was not seen frequently in the distal upper extremity 30 to 40 years ago except in patients with Buerger disease. This is a fairly common problem now and is primarily related to the combination of diabetes, renal disease, and often organ transplantation. The need for access for hemodialysis compounds this problem by potentially altering the circulation distal to the site of the arteriovenous fistula. Patients with collagen vascular disease often suffer from vasospastic disease (see later), but they can also have vascular occlusion from the effects of vasculitis. Today, Buerger disease is an uncommon cause of ischemia of the hand, but it would appear that other disease states leading to critical ischemia of the hand are on the rise. Many patients have already suffered loss of one or both of their lower extremities, and loss of the hand can be devastating from the mobility standpoint. Therefore, I feel that an aggressive approach is warranted for these patients to try and avoid loss of the hand.
Preoperative Evaluation
Patients presenting with ischemia of the hand in the face of vascular disease need a thorough workup. The presence or absence of pulses at the wrist is important, but if absent, they should be sought out with a pencil Doppler. In the absence of a palpable pulse, the presence of a pulse with use of the Doppler is not a sign of adequate nutritive flow to the hand, however. As noted previously, I also use a “dynamic” Doppler to listen to the arch and sequentially occlude the wrist’s radial and ulnar arteries. The flow to the fingers should be evaluated for the presence or absence of a signal in the pulp as well. Ischemic, gangrenous, or ulcerated fingers should be noted. Likewise, any previous surgery to the hand and arm should be noted, particularly prior or currently functional vascular access procedures.
The Doppler signal at the wrist should be evaluated with the fistula open and with it occluded with digital pressure to note any improvement in flow with the fistula occluded. Generally, arteriography remains the gold standard for most patients with critical ischemia of the hand because proper evaluation requires good visualization of the forearm vessels, palmar arch, and digital vessels that is difficult to achieve with MRA or CTA. Many patients present from the vascular surgeon with results of an arteriography, but I feel very strongly that the surgeon planning vascular intervention in the hand must view the actual studies.
After exam, all patients who have not had arterial studies should undergo arteriography. Many patients with critical ischemia due to complications of diabetes and renal disease will have multiple levels of partial occlusion that can be seen in the forearm vessels on arteriography, and these types of lesion do not lend themselves to a local approach ( Figure 60.21 ). Patients with collagen vascular disease usually have an occlusion limited to the vessels in the distal forearm and/or hand, but the digital vessels may be involved as well. The arteriogram should be used to decide the best approach to improve flow to patients’ hand. In the case of ulnar or radial artery thrombosis in the distal forearm and hand, excision of the occluded segment to accomplish a Leriche sympathectomy with bypass grafting usually is indicated. The approach is similar to that discussed earlier for ulnar and radial artery thrombosis.
Patients with multisegment disease require a more aggressive approach. Bypass can be performed in the forearm of occluded areas using saphenous vein grafting very successfully ( Figure 60.22 ). For most patients, however, I feel that going from the proximal brachial artery above all sites of occlusion to an open ulnar or radial artery at the wrist level usually is the most successful option. Patients often have lower-extremity vascular disease and the saphenous may not be available as a result of prior harvesting (e.g., for extremity or cardiac surgery) or because of loss of the lower limb. I have also found that healing of the saphenous donor site in the lower and upper leg can be very problematic in this patient group. The saphenous is quite thick and can present difficulties in anastomosis to the hand’s smaller vessels. For all of these reasons, I prefer to do an in situ bypass technique in the hand, generally using the cephalic vein to go from the brachial to the radial artery in the snuffbox if the arch is open (see Figure 60.21, B ).
Author’s Preferred Method of Treatment: In Situ Bypass of the Forearm
I prefer to use the cephalic vein for in situ bypass whenever possible because the radial artery in the snuffbox usually is patent in patients with significant vascular disease. The radial artery bifurcates deep in the snuffbox into the princeps pollicis and deep palmar arch; anastomosis usually is done just proximal to this bifurcation. Even with severe calcific arterial disease, there is a segment of the artery just before the bifurcation that is soft enough to sew with a 7-0 or 8-0 suture. Due to the nature of these patients, the cephalic vein may not be patent or partially thrombosed; thus, it is wise to examine this vein prior to undertaking surgical intervention.
In case the cephalic is unusable, the basilic is an option but will not reach the radial artery, so the distal anastomosis must be done to the ulnar arch. In cases in which both of the vessels cannot be used, the reversed saphenous vein remains an option. At times, the only way to be certain about the patency and/or adequacy of these veins is by exploring them, and it must be explained preoperatively to the patient and family that another incision on the leg may be necessary.
An incision is made from over the snuffbox to the antecubital fossa over the brachial artery, largely following the course of the cephalic vein, which is carefully exposed and all branches are sought out. The bigger branches are preserved to allow passage of the valvulotome, while the smaller branches are ligated with little vascular clips. Enough vein is dissected out proximally and distally to have adequate length for the graft to reach the brachial and radial arteries proximally and distally, respectively. The brachial artery is dissected free in the antecubital fossa, and blue vascular loops are placed on branches to provide proximal and distal control.
Similarly, the radial artery is dissected out from the snuffbox to the site of the bifurcation and an appropriate place for anastomosis is selected (e,g., primarily an area with minimal calcification if this can be located). The larger branches of the cephalic are controlled with small vascular clamps or bulldogs; once the sites for anastomosis are selected proximally and distally, the vein is divided at appropriate sites to allow enough for proximal and distal anastomoses. The vein is then irrigated and the valves are removed carefully with the Leather-Mills valvulotome. This instrument comes in forward-cutting (i.e., antegrade placement) and reverse-cutting (i.e., retrograde placement) styles. I prefer the retrograde reverse-cutting model because it seems to be safer and more able to be controlled ( Figure 60.23 ).
