Key Words:
lower extremity trauma , mangled extremity , tourniquet , vascular shunt , venous injury , arterial injury , amputation
Introduction
Vascular injury to the lower extremity is a common pattern of vascular trauma. Injuries to junctional zone vessels are especially challenging and potentially lethal. Foremost, injury to the distal iliac and proximal femoral arteries and veins poses a challenge with hemorrhage control. The term junctional vascular injury was a product of the military’s recognition during the wars in Afghanistan and Iraq that, although tourniquets were effective in controlling lower extremity hemorrhage, they did not work if the penetrating wounds were too proximal on the lower extremity (i.e., the junctional zone between the torso and the lower extremity). Furthermore, injury to the distal iliac and proximal femoral arteries resulting in hemorrhage is often very difficult for a medic or bystander to control with manual pressure because the vessels are either large or deep under the inguinal ligament and the distal pelvic outlet. Because of this injury pattern’s propensity for exsanguinating hemorrhage, the military has coined the term “junctional lower extremity vascular injury” to facilitate study and to improve management strategies. More distal injuries such as those to the femoral, popliteal, and tibial segments may also lead to lethal hemorrhage; but from a practical standpoint these injuries are amenable to tourniquet control. Lower extremity vascular trauma at any anatomic level poses challenges not only related to control of bleeding but also with regard to decisions related to restoration of perfusion and reconstruction of the vascular injury.
History and Background
When considering those who died of combat wounds from 2001 to 2009, nearly 41% had potentially survivable injuries if hemorrhage had been controlled in a more prompt and effective manner. In this context, potentially survivable death means mortality that occurred in the absence of a lethal head or cardiac wound or body disruption from explosive injury. The body regions accounting for death with otherwise survivable injuries include trauma to the torso (48%), to the extremities (31%), and to the junctional region (21%). Table 15-1 shows the incidence of lower extremity vascular injury in military conflicts, past and present. The rate of exsanguination from torso trauma has decreased over the years possibly due to the use of body armor. Similarly, the rate of extremity hemorrhage has decreased likely due to the broad distribution, training, and use of tourniquets. With improvements in body armor, which protects from central torso trauma, injury to the extremity vessels has contributed a larger percentage of overall vascular injuries. Lower extremity vascular injuries will likely continue to be common due to practical limitations associated with extremity and junctional zone armor.
| War | Iliac Vessels | Femoral Vessels | Popliteal Vessels | Tibial Vessels |
|---|---|---|---|---|
| World War I | 1% | 35% | 12% | 11% |
| World War II | 2% | 21% | 20% | 20% |
| Korean War | 2% | 31% | 26% | 18% |
| Vietnam War | 3% | 35% | 22% | 0% |
| Iraq and Afghanistan | 2% | 28% | 9% | 10% |
Lower extremity vascular injury is also common in the civilian setting where injuries to the iliac artery and vein have a higher incidence than in the military setting. Mattox et al documented 232 iliac artery injuries and 289 vein injuries, representing 4% and 5%, respectively, of all vascular injuries in a single-center civilian registry. Femoral and popliteal vessel injuries are more common than iliac vessel injuries in civilian trauma centers, which likely reflects their longer extent and exposed position. In a report by Branco et al femoral vessel injury comprised approximately 25% of all extremity vascular injuries. Comparatively, Asensio et al reported femoral vessel injuries to be even more common, accounting for nearly 70% of peripheral vascular injuries. However, in isolated lower extremity trauma, the most commonly injured artery is the popliteal, with the majority of injuries resulting from blunt mechanism. Blunt injuries are more likely to be associated with orthopedic fractures or dislocations and likely to result in longer hospital stays and higher rates of amputation than other lower forms of extremity arterial injury.
Similarly, the number of tibial artery injuries and the proportion of all vascular injuries they represent have increased in the past number of years. A recent single institution study of lower extremity vascular trauma reported that the tibial arteries were the most commonly injured vessels and accounted for 36% of cases. The most common mechanism of tibial artery injury is gunshot wound (37%) with motor-vehicle accidents (26%) contributing a significant portion as well.
Presentation and Diagnosis
Assessment of a patient with a potential lower extremity injury or a junctional zone vascular injury follows a standard approach outlined in the Advanced Trauma Life Support (ATLS) program developed by the American College of Surgeons (ACS) and its Committee on Trauma (COT). Foremost, control of bleeding with a tourniquet or manual pressure is necessary to prevent exsanguination. Depending on the location, if a standard Combat Application Tourniquet (C-A-T’ North American Rescue, LLC, Greer, SC) is not available, a manual blood pressure cuff may be inflated proximal to the injury to act as a tourniquet to control bleeding. As described, the vexing problem lies with junctional vascular injuries which are not amenable to tourniquet application and are difficult to control with manual pressure. In these instances, manual pressure with or without a topical hemostatic agent such as Combat Gauze (Z-Medica Corporation, Wallingford, CT) and rapid operative control may be necessary.
In the absence of significant hemorrhage, one has time to examine the lower extremity including assessing the femoral, popliteal, and pedal pulses. Palpation in the resuscitation room or intensive care unit is subjective and prone to false positive or negative recordings, and this portion of the examination should be augmented with continuous-wave Doppler. The utility of Doppler ultrasound in the diagnosis of extremity vascular injury is detailed in Chapter 5 of this textbook. At the time of palpation of pulses, the injured lower extremity should be assessed for hard or soft vascular injury. Hard signs are grouped as clear or obvious indicators of blood vessel disruption or occlusion and include pulsatile bleeding, expanding hematoma, palpable thrill, audible bruit or profound ischemia distal to the point of injury. Soft signs are suggestive of vascular injury but less obvious. These include reports of bleeding at the scene of injury, the presence of a peripheral nerve deficit, an injury pattern (including long-bone fracture or dislocation, indicative of vascular compromise), and injury in close proximity to a main or axial extremity vessel.
In nearly all cases, the presence of hard signs of extremity vascular injury indicates the need for prompt operative intervention. In the presence of confounding factors such as penetrating wounds to multiple levels of the lower extremity, arteriography or other imaging such as duplex or computed tomographic angiography (CTA) may be appropriate even in the setting of hard signs. In the presence of soft signs of vascular injury, using the continuous-wave Doppler to calculate the injured extremity index (IEI) is necessary. Initially, the quality of the audible arterial signal in the distal aspect of the injured extremity (wrist, ankle and foot) gives the examiner information regarding the nature of perfusion to the limb. For example, a strong, clearly audible, bi- or triphasic arterial signal is typically normal and noticeably different than a weak monophasic signal, which may be an indicator of vascular injury. However, the quality of the audible signal is also somewhat subjective and may be influenced by a patient who is cold and hypotensive. A more objective modality using the continuous-wave Doppler and a manual blood pressure cuff is the IEI.
The IEI is a measure of the arterial occlusion pressure of the audible Doppler signal in the distal aspect of the injured limb compared to the occlusion pressure in one of the other noninjured extremities. This measurement or ratio is the same as the ankle-brachial index (ABI) that is used in the diagnosis of arterial occlusive disease in the lower extremity. In the setting of trauma and because the comparison may be between the occlusion pressure in an injured upper extremity to that in the noninjured upper extremity, this ratio is also referred to as the IEI. In the absence of vascular injury, the ratio of the occlusion pressures between the injured and noninjured extremities should be 0.9 or greater. An IEI of less than 0.9, especially in a patient with a normal contralateral IEI, indicates a flow-limiting abnormality and has been shown to correlate with identifiable arterial injury.
Importantly, the IEI should be repeated in patients who are hypothermic and/or hypotensive as these factors may result in initial false negative ratios. The IEI should also be repeated in patients who have an extremity fracture or dislocation after the orthopedic injury has been reduced or aligned with traction. In patients with these types of extremity injuries, the Doppler signal and therefore the IEI may improve with resuscitation, warming, and fracture reduction. However, an IEI that is persistently less than 0.9 should be considered to indicate arterial injury, and one should pursue further imaging or operative exploration. In most cases in which there are soft signs of vascular injury and a persistently diminished IEI further diagnostic imaging such as duplex ultrasound, CTA, or conventional arteriography is performed. In complex cases, arteriography should be performed in the operating room (OR) using a mobile or fixed fluoroscopic imaging system to provide access to all options including definitive operative exploration if necessary. In cases of extremity fracture or dislocation, performance of arteriography in the OR may be combined with procedures such as fracture reduction or fixation.
Junctional Distal Iliac and Proximal Femoral Injuries
Injury to the external iliac vessels should be suspected in all penetrating injuries to the junctional zone including wounds to the lower quadrants of the abdomen, hips, buttocks, and groins ( Fig. 15-1 ). Symptoms of iliac vessel injury are the same as those to the more commonly recognized lower extremity vessels but may also include abdominal distension, evidence of bowel injury (e.g., rectal blood), or a suggestion of genitourinary injury (e.g., hematuria, blood in the vagina or at the penile meatus). In the setting of penetrating lower abdominal or pelvic injury, the absence of femoral pulse(s) or a discrepancy between the femoral pulses should alert the provider to the likelihood of an iliac artery injury.
The soft sign of a junctional vascular injury may initially be proximity of a lower abdominal or pelvic wound to the external iliac vessels. In these cases, the provider must have a high index of suspicion to pursue additional imaging or operative exploration. Further imaging is not generally indicated in patients who are hemodynamically unstable with penetrating lower abdominal or pelvic injury. Instead, these patients should be managed with operative exploration in conjunction with balanced, blood component-based resuscitation. In cases of penetrating lower abdominal trauma, exploration will require exploratory laparotomy to achieve vascular control and hemostasis. If patients with lower abdominal or pelvic injuries are hemodynamically normal, further imaging is useful and can include plain radiographs of the abdomen and pelvis followed by CTA. In addition to providing detail regarding intraabdominal and retroperitoneal structures and pelvic fracture, CTA may demonstrate contrast extravasation from or occlusion of an iliac or proximal femoral vessel. In these instances, CTA provides a quick and detailed assessment of injury allowing for better operative planning including the sequence of steps and the selective use of endovascular techniques.
In contrast to penetrating trauma, iliac injury from blunt mechanisms often presents with more gradual, insidious blood loss. If the patient has an unstable pelvic fracture, early application of a pelvic sheet or binder is indicated and should precede additional diagnostic workup. Early application of a binder around the pelvis is especially useful in controlling venous bleeding associated with complex pelvic fractures and works by stabilizing the fracture and inducing tamponade. In some instances of pelvic fracture with hemodynamic instability, arteriography with the option of embolization of bleeding is helpful. This is especially true if contrast extravasation is observed from a branch or branches of the internal iliac arteries on the initial CTA. Increasingly, embolization of bleeding vessels can be pursued in an endovascular OR that is able to accommodate catheter-based procedures as well as traditional open operations.
Femoral and Popliteal Injuries
Patients with femoral or popliteal vascular trauma may present with hard or soft signs of injury. However, experience shows that most injuries in this location are accompanied by hemorrhage and/or ischemia at some point following the event. In some cases, limb-threatening complications may result from overlooking or missing the hard signs of vascular injury because the active bleeding will have stopped or the degree of ischemia will be incomplete. Although most cases of femoral or popliteal trauma with hard signs require prompt operative intervention, contrast arteriography or CTA may be useful in more complex scenarios. In cases of mangled lower extremity with vascular and orthopedic components, the location of fracture(s) and vascular injury may be best determined with arteriography or CTA. Management of the extremity with multiple penetrating wounds at different levels of the limb may also be aided with arteriography and/or CTA before operation. In these cases although hard signs of bleeding and/or ischemia may be present, the level of the injury and therefore it may not be possible to determine the location of operation without contrast imaging. Physical examination alone has been shown to be associated with a false positive rate as high as 87%. The amputation rate for patients with blunt extremity trauma has been reported to be extremely high due to missed injuries. Surgeons must maintain a high index of suspicion for popliteal artery injuries in any patient with anterior or posterior knee dislocations, distal femur fractures or tibial plateau fractures. In some situations, the diagnostic adjunct of intraoperative arteriography may reduce the rate of negative surgical exploration. Recent studies support a practice of selective arteriography and operative exploration based on IEI, duplex ultrasound, and CTA. The uses of this strategy contrast arteriography and operative exploration are reserved for instances in which one or more of these noninvasive modalities are abnormal. This selective approach to arteriography and operation for posterior knee dislocation has been shown to be safe and effective and has reduced the rate of negative or nontherapeutic exploration ( Figs. 15-2 and Fig. 15-3 ).
Tibial Level Injuries
The redundant nature of perfusion to the ankle and foot through three tibial arteries (anterior, posterior, and peroneal) means that vascular trauma at this level is better tolerated than that to more proximal levels of the lower extremity. In order for limb-threatening ischemia to result from trauma at this level, all three tibial vessels must be disrupted which is uncommon. In the civilian setting, patients with penetrating injuries to the leg (i.e., below the knee) have been shown to be less likely to present with signs of ischemia than those with blunt trauma (33% vs. 68%, respectively). This observation may be partly due to the redundant nature of perfusion and the fact that penetrating wounds are less likely to affect all of the tibial arteries. In contrast, blunt trauma to the leg often results in complex tibia and fibula fractures (i.e., Gustillo fractures) which are more prone to injure all of the tibial arteries and result in ischemia. Studies have shown that when tibial vessels are injured by blunt mechanisms, they injuries are almost always associated with a fracture (97%). Blunt mechanisms leading to tibial vascular trauma may also result in open fractures with soft-tissue injuries (59% of cases) and peripheral nerve injuries (53% of cases). Less commonly, penetrating trauma leading to tibial vascular injury is associated with fracture (31% of cases), soft-tissue injury (6% of cases), and nerve dysfunction (20% of cases). Like the diagnosis of popliteal artery injury, imaging of the tibial vessels should be performed selectively. In most cases, contrast arteriography and/or exploration of the tibial arteries is reserved for patients with persistent signs of ischemia such as a diminished IEI (<0.90).
Junctional Distal Iliac and Proximal Femoral Injuries
Injury to the external iliac vessels should be suspected in all penetrating injuries to the junctional zone including wounds to the lower quadrants of the abdomen, hips, buttocks, and groins ( Fig. 15-1 ). Symptoms of iliac vessel injury are the same as those to the more commonly recognized lower extremity vessels but may also include abdominal distension, evidence of bowel injury (e.g., rectal blood), or a suggestion of genitourinary injury (e.g., hematuria, blood in the vagina or at the penile meatus). In the setting of penetrating lower abdominal or pelvic injury, the absence of femoral pulse(s) or a discrepancy between the femoral pulses should alert the provider to the likelihood of an iliac artery injury.
The soft sign of a junctional vascular injury may initially be proximity of a lower abdominal or pelvic wound to the external iliac vessels. In these cases, the provider must have a high index of suspicion to pursue additional imaging or operative exploration. Further imaging is not generally indicated in patients who are hemodynamically unstable with penetrating lower abdominal or pelvic injury. Instead, these patients should be managed with operative exploration in conjunction with balanced, blood component-based resuscitation. In cases of penetrating lower abdominal trauma, exploration will require exploratory laparotomy to achieve vascular control and hemostasis. If patients with lower abdominal or pelvic injuries are hemodynamically normal, further imaging is useful and can include plain radiographs of the abdomen and pelvis followed by CTA. In addition to providing detail regarding intraabdominal and retroperitoneal structures and pelvic fracture, CTA may demonstrate contrast extravasation from or occlusion of an iliac or proximal femoral vessel. In these instances, CTA provides a quick and detailed assessment of injury allowing for better operative planning including the sequence of steps and the selective use of endovascular techniques.
In contrast to penetrating trauma, iliac injury from blunt mechanisms often presents with more gradual, insidious blood loss. If the patient has an unstable pelvic fracture, early application of a pelvic sheet or binder is indicated and should precede additional diagnostic workup. Early application of a binder around the pelvis is especially useful in controlling venous bleeding associated with complex pelvic fractures and works by stabilizing the fracture and inducing tamponade. In some instances of pelvic fracture with hemodynamic instability, arteriography with the option of embolization of bleeding is helpful. This is especially true if contrast extravasation is observed from a branch or branches of the internal iliac arteries on the initial CTA. Increasingly, embolization of bleeding vessels can be pursued in an endovascular OR that is able to accommodate catheter-based procedures as well as traditional open operations.
Femoral and Popliteal Injuries
Patients with femoral or popliteal vascular trauma may present with hard or soft signs of injury. However, experience shows that most injuries in this location are accompanied by hemorrhage and/or ischemia at some point following the event. In some cases, limb-threatening complications may result from overlooking or missing the hard signs of vascular injury because the active bleeding will have stopped or the degree of ischemia will be incomplete. Although most cases of femoral or popliteal trauma with hard signs require prompt operative intervention, contrast arteriography or CTA may be useful in more complex scenarios. In cases of mangled lower extremity with vascular and orthopedic components, the location of fracture(s) and vascular injury may be best determined with arteriography or CTA. Management of the extremity with multiple penetrating wounds at different levels of the limb may also be aided with arteriography and/or CTA before operation. In these cases although hard signs of bleeding and/or ischemia may be present, the level of the injury and therefore it may not be possible to determine the location of operation without contrast imaging. Physical examination alone has been shown to be associated with a false positive rate as high as 87%. The amputation rate for patients with blunt extremity trauma has been reported to be extremely high due to missed injuries. Surgeons must maintain a high index of suspicion for popliteal artery injuries in any patient with anterior or posterior knee dislocations, distal femur fractures or tibial plateau fractures. In some situations, the diagnostic adjunct of intraoperative arteriography may reduce the rate of negative surgical exploration. Recent studies support a practice of selective arteriography and operative exploration based on IEI, duplex ultrasound, and CTA. The uses of this strategy contrast arteriography and operative exploration are reserved for instances in which one or more of these noninvasive modalities are abnormal. This selective approach to arteriography and operation for posterior knee dislocation has been shown to be safe and effective and has reduced the rate of negative or nontherapeutic exploration ( Figs. 15-2 and Fig. 15-3 ).
Tibial Level Injuries
The redundant nature of perfusion to the ankle and foot through three tibial arteries (anterior, posterior, and peroneal) means that vascular trauma at this level is better tolerated than that to more proximal levels of the lower extremity. In order for limb-threatening ischemia to result from trauma at this level, all three tibial vessels must be disrupted which is uncommon. In the civilian setting, patients with penetrating injuries to the leg (i.e., below the knee) have been shown to be less likely to present with signs of ischemia than those with blunt trauma (33% vs. 68%, respectively). This observation may be partly due to the redundant nature of perfusion and the fact that penetrating wounds are less likely to affect all of the tibial arteries. In contrast, blunt trauma to the leg often results in complex tibia and fibula fractures (i.e., Gustillo fractures) which are more prone to injure all of the tibial arteries and result in ischemia. Studies have shown that when tibial vessels are injured by blunt mechanisms, they injuries are almost always associated with a fracture (97%). Blunt mechanisms leading to tibial vascular trauma may also result in open fractures with soft-tissue injuries (59% of cases) and peripheral nerve injuries (53% of cases). Less commonly, penetrating trauma leading to tibial vascular injury is associated with fracture (31% of cases), soft-tissue injury (6% of cases), and nerve dysfunction (20% of cases). Like the diagnosis of popliteal artery injury, imaging of the tibial vessels should be performed selectively. In most cases, contrast arteriography and/or exploration of the tibial arteries is reserved for patients with persistent signs of ischemia such as a diminished IEI (<0.90).
Preoperative Preparation
Computed tomography is an important adjunct in preoperative preparation in the hemodynamically stable blunt trauma patient. This imaging modality can also be a useful adjunct in select patients with penetrating trauma who have normal hemodynamic measures and equivocal physical examination findings. Extravasation of contrast from a vascular structure is indicative of vessel injury. Even in the absence of active extravasation, pelvic hematoma can be a sign of venous injury or bleeding from the internal iliac artery or from smaller branches. Lack of contrast within the vascular lumen can be indicative of thrombosis or dissection causing a reduction in flow. In cases of diagnosed or suspected vascular injury on CT, angiographic evaluation may be useful and may provide the possibility of catheter-based intervention. The utility of multidetector computed tomographic angiography (MDCTA) may be limited in some patterns of penetrating trauma, especially those associated with retained metallic fragments from firearm or other explosive mechanisms. In these instances, the metallic fragments may cause artifacts, which make interpretation of the adjacent vessels difficult. However, even in the presence of metallic artifact, MDCTA often provides important diagnostic information ( Fig. 15-4 ). Inaba et al provided an important study of MDCTA and showed its value in managing severe lower extremity injury. In their study, only 1 of 63 scans was indeterminate due to retained metallic artifact; and the rest provided elements of important diagnostic information helping guide management. Furthermore, in their clinical series, three injuries distal to the knee were evaluated by conventional arteriography after MDCTA, and in all cases the arteriogram confirmed MDCTA providing no additional information. Moreover, in White et al’s analysis of MDCTA in the evaluation of vascular trauma, additional benefits were delineated. In this study, multiple extremities (i.e., simultaneous) were evaluated in 15 of 20 CT studies. Most commonly, this meant both lower extremities were evaluated with one study, but an upper and a lower extremity could be evaluated simultaneously as well. This study also demonstrated that MDCTA was diagnostic in the presence of retained metallic fragments. Finally, the study by White and colleagues showed that MDCTA also provided useful diagnostic information in 8 of 10 patients with external fixator devices or intramedullary nails in place. Together, these experiences confirmed that MDCTA is a useful diagnostic option to detect vascular injury when one has a high index of suspicion, even in the absence of hard signs or a normal IEI examination.
Junctional Distal Iliac and Proximal Femoral Injuries
As stated previously, control of hemorrhage from junctional injuries can be difficult and must first be managed with direct compression. Operative exposure and/or control of junctional vascular injuries typically requires either an inguinal or a transplant incision ( Fig. 15-5 ) to gain access to the external iliac artery and vein. Once exposed, the common or external iliac or common femoral arteries can be controlled using vascular clamps. Additional techniques and devices to rapidly apply pressure to junctional vascular injuries in the pre- and out-of-hospital settings have been developed including the Combat Ready Clamp (CRoC; Combat Medical Systems, Fayetteville, NC) and the Junctional Emergency Treatment Tool (JETT; North American Rescue, Greer, SC). These devices are designed to be placed on the patient by initial responders in the tactical environment (e.g., Tactical Combat Casualty Care) and include mechanical properties that allow compression of the distal external iliac and proximal femoral vessels. The utility of the CRoC, JETT, and other emerging adjuncts to control junctional vascular injury has not been fully evaluated. However, promising reports on their efficacy have been registered from the terminal stages of the war in Afghanistan and anecdotal cases of civilian trauma. Despite successes associated with the development of a small number of junctional hemorrhage control devices, further research is needed to develop approaches or tools to control noncompressible torso and junctional hemorrhage at the point of injury and in the acute, out-of-hospital phase of care.
Femoral and Popliteal Injuries
In the case of extremity trauma, hemorrhage control strategies including tourniquets and topical hemostatic agents have been successfully codified in the Committee on Tactical Combat Casualty Care’s (TCCC’s) PreHospital Trauma Life Support (PHTLS) manual. Considerable detail on the contributions of the TCCC and the PHTLS manual is provided in the Chapter 15 of this textbook. The TCCC guidelines emphasize three objectives: Treat the patient, prevent additional casualties, and complete the mission. Advances in the prehospital care of those with femoral and popliteal vascular trauma put forth by the TCCC include prompt hemorrhage control, establishment of intravenous or intraosseus access, and use of fluid resuscitation in only those patients who are in shock. Training and adherence to these and other PHTLS guidelines has been shown by Kotwal and colleagues to reduce preventable death in wounded service personnel.
If extremity hemorrhage cannot be controlled with direct pressure, prompt application of a tourniquet should be performed. Tightening of the tourniquet should continue until arterial bleeding from the limb has stopped or until distal pulses are no longer palpable ( Fig. 15-6 ). If a single tourniquet is not successful in controlling extremity hemorrhage, a second tourniquet should be applied to increase the effective tourniquet width. Kragh and others from the United States Army Institute of Surgical Research reported that the application and use of tourniquets to control extremity bleeding before the onset of shock resulted in lower mortality than application of tourniquets after the onset of hemodynamic instability. The importance of the proper application of the tourniquet cannot be overemphasized as incorrect placement is associated with mortality from hemorrhage. In addition to their effectiveness, properly applied tourniquets are safe. In a clinical series of 428 tourniquets applied on 309 severely injury limbs, the incidence of nerve palsy was 1.7%. There was no association with vascular thrombosis, myonecrosis, rigor, pain, fasciotomy, or renal failure. It is important to understand the success of tourniquets in the wars in Afghanistan and Iraq in the context of short medical evacuation and therefore relatively short tourniquet times. Reports from those wars and clinical experience of the editors suggest that the vast majority of tourniquets applied during the wars in Afghanistan and Iraq were in place for 2 hours or less. Clearly tourniquet application and the potential adverse effects of complete limb ischemia for longer periods of time in future military or civilian scenarios will need to be reappraised.
Tibial Level Injuries
Tibial vascular injury may be the result of penetrating or blunt trauma and is most commonly associated with fracture of the tibia or fibula. The order or priority of injury management in these cases is dictated by the presence or absence of hemorrhage and/or complete ischemia. In cases in which control of bleeding is difficult, exploration of the vascular injury with ligation of the vessel or placement of a temporary vascular shunt may be necessary before fracture reduction and stabilization. The same is true in some cases in which there is complete ischemia (i.e., no audible Doppler signal) of the leg below the injury. However, in most instances, fracture reduction or traction and stabilization can be performed promptly and results in restoration of perfusion to the leg and foot. If evidence of arterial ischemia persists (i.e., IEI less than 0.9) after maneuvers to reduce and stabilize the fracture, further diagnostic evaluation such as CTA or arteriography may be required. Alternatively—and especially in the setting of open, penetrating wounds—the tibial vessel(s) can be explored and evaluated, directly obviating the need for additional imaging ( Fig. 15-7 ).
Junctional Distal Iliac and Proximal Femoral Injuries
As stated previously, control of hemorrhage from junctional injuries can be difficult and must first be managed with direct compression. Operative exposure and/or control of junctional vascular injuries typically requires either an inguinal or a transplant incision ( Fig. 15-5 ) to gain access to the external iliac artery and vein. Once exposed, the common or external iliac or common femoral arteries can be controlled using vascular clamps. Additional techniques and devices to rapidly apply pressure to junctional vascular injuries in the pre- and out-of-hospital settings have been developed including the Combat Ready Clamp (CRoC; Combat Medical Systems, Fayetteville, NC) and the Junctional Emergency Treatment Tool (JETT; North American Rescue, Greer, SC). These devices are designed to be placed on the patient by initial responders in the tactical environment (e.g., Tactical Combat Casualty Care) and include mechanical properties that allow compression of the distal external iliac and proximal femoral vessels. The utility of the CRoC, JETT, and other emerging adjuncts to control junctional vascular injury has not been fully evaluated. However, promising reports on their efficacy have been registered from the terminal stages of the war in Afghanistan and anecdotal cases of civilian trauma. Despite successes associated with the development of a small number of junctional hemorrhage control devices, further research is needed to develop approaches or tools to control noncompressible torso and junctional hemorrhage at the point of injury and in the acute, out-of-hospital phase of care.
Femoral and Popliteal Injuries
In the case of extremity trauma, hemorrhage control strategies including tourniquets and topical hemostatic agents have been successfully codified in the Committee on Tactical Combat Casualty Care’s (TCCC’s) PreHospital Trauma Life Support (PHTLS) manual. Considerable detail on the contributions of the TCCC and the PHTLS manual is provided in the Chapter 15 of this textbook. The TCCC guidelines emphasize three objectives: Treat the patient, prevent additional casualties, and complete the mission. Advances in the prehospital care of those with femoral and popliteal vascular trauma put forth by the TCCC include prompt hemorrhage control, establishment of intravenous or intraosseus access, and use of fluid resuscitation in only those patients who are in shock. Training and adherence to these and other PHTLS guidelines has been shown by Kotwal and colleagues to reduce preventable death in wounded service personnel.
If extremity hemorrhage cannot be controlled with direct pressure, prompt application of a tourniquet should be performed. Tightening of the tourniquet should continue until arterial bleeding from the limb has stopped or until distal pulses are no longer palpable ( Fig. 15-6 ). If a single tourniquet is not successful in controlling extremity hemorrhage, a second tourniquet should be applied to increase the effective tourniquet width. Kragh and others from the United States Army Institute of Surgical Research reported that the application and use of tourniquets to control extremity bleeding before the onset of shock resulted in lower mortality than application of tourniquets after the onset of hemodynamic instability. The importance of the proper application of the tourniquet cannot be overemphasized as incorrect placement is associated with mortality from hemorrhage. In addition to their effectiveness, properly applied tourniquets are safe. In a clinical series of 428 tourniquets applied on 309 severely injury limbs, the incidence of nerve palsy was 1.7%. There was no association with vascular thrombosis, myonecrosis, rigor, pain, fasciotomy, or renal failure. It is important to understand the success of tourniquets in the wars in Afghanistan and Iraq in the context of short medical evacuation and therefore relatively short tourniquet times. Reports from those wars and clinical experience of the editors suggest that the vast majority of tourniquets applied during the wars in Afghanistan and Iraq were in place for 2 hours or less. Clearly tourniquet application and the potential adverse effects of complete limb ischemia for longer periods of time in future military or civilian scenarios will need to be reappraised.
