Chapter 96. Pelvic Ring Injuries and Extremity Trauma

• Hemorrhage from pelvic injuries is underestimated frequently, leading to delayed diagnosis and treatment.
• Pelvic ring injuries frequently are associated with other significant injuries resulting in major morbidity and mortality.
• Management of pelvic injuries initially requires hemorrhage control and volume resuscitation.
• Temporary external fixation is a key element in the initial control of hemorrhage from pelvic fractures.
• Extremity fractures, though frequently not life threatening, require accurate diagnosis and appropriate management to prevent significant morbidity.
• Complications of extremity injuries, such as compartment syndrome and neurovascular compromise, can best be avoided by a high index of suspicion, careful assessment, and institution of appropriate preventive measures.
• Knowledge of the mechanism of injury is crucial in predicting the type and severity of extremity injuries.

Patients sustaining major pelvic and extremity trauma frequently are managed in the ICU setting. These patients may present with significant hemodynamic abnormality owing to their associated injuries, and this can be compounded by inadequate resuscitation resulting from underestimation of the volume of blood loss associated with such injuries. The following information is provided to assist the intensivist in understanding extremity and pelvic ring injuries, thus allowing early diagnosis with prompt and appropriate management aimed at preventing major morbidity and mortality.

Significant force is required to sustain an injury to the pelvic ring. In various epidemiologic studies, mortality rates of up to 25% have been reported, depending on the pattern and severity of the pelvic injury.1,2 While the direct cause of death is usually attributed to a head or thoracic injury,3 pelvic bleeding significantly contributes to this high rate of mortality. There is an increased risk of mortality in association with open pelvic fractures, a high injury severity score (ISS), or concomitant head, thoracic, abdominal, or neurologic injury.4

When the body is subjected to such forces, other injuries are very common. On presentation to the hospital, 15% of patients with pelvic ring injuries are hemodynamically unstable, 66% have a closed head injury, 25% have a thoracic injury, 20% have an abdominal injury, 20% have a urologic injury, and 8% have a lumbosacral injury.3 A team approach is required to treat trauma victims adequately, including the trauma team leader, surgical team (general, thoracic, orthopedic, and neurosurgery), and intensivist.

Anatomy

The pelvis is composed of the two innominate bones (hemipelvis) and the sacrum joined anteriorly by the pubic symphysis and posteriorly by the anterior and posterior sacroiliac ligaments, as well as the interosseous sacroiliac ligaments. Within the pelvic floor, the pelvis is further reinforced by the sacrospinous and sacrotuberous ligaments, as well as the muscles and fascia of the pelvic floor (Fig. 96-1).

Running over the sacral ala and into the pelvis are the common iliac artery and vein, bifurcating to the internal and external iliac vessels above and below the pelvic brim, respectively. These vessels run close to the innominate bones, thus making them vulnerable to injury with any disruption of the pelvic ring. In particular, there is a plexus of veins running along the walls of true pelvis below the pelvic brim that is commonly disrupted by pelvic injuries, contributing to the rapid venous blood loss seen with these injuries (Fig. 96-2).

Arterial injuries are less common, accounting for 20% of pelvic exsanguinating deaths.5 The arteries most at risk are the internal pudendal, superior gluteal, obturator, and lateral sacral arteries, usually as they exit the pelvis or at a branching or tethering point within the pelvis.

The bladder lies directly behind the pubic symphysis, with the urethra exiting inferiorly, making both these structures vulnerable to injury. Similarly, the sigmoid colon and rectum are vulnerable as they run along the posterior pelvis and through the pelvic floor.

The lumbar and lumbosacral plexi composed of the ventral nerve roots also lie against the posterior pelvis, and the resulting peripheral nerves, particularly the sciatic nerve, can be injured as they exit the pelvis. The sacral nerve roots are particularly vulnerable with injuries that involve a fracture through the sacral foramen.

Mechanism and Injury Classification

The mechanism of injury is an important part of the presenting history in that it can be used to predict what type of pelvic injury has been sustained, as well as the pattern of associated head, thoracic, abdominal, and extremity injuries.2 For example, in motor vehicle crashes, side impacts are more likely to result in a pelvic ring injury than a frontal impact.6 Associated injuries that can be expected with a side impact include a closed head injury, cervical spine injury, rib fractures with pneumo- or hemothorax, splenic or liver laceration, lateral compression pelvic injury, and ipsilateral extremity fractures. A fall from a height has a pattern of injury including closed head injury, shearing injuries of the great vessels in the thorax, spinal burst fractures, vertical shear injuries of the pelvis, femoral neck fractures, and other lower extremity fractures.

Several pelvic fracture classifications exist to assist in deciding the appropriate treatment. The Young-Burgess classification stratifies the injury first by mechanism, i.e., anteroposterior compression (APC), lateral compression (LC), vertical shear (VS), and combined, and then subclassifies by severity of injury (Fig. 96-3). Higher grades of injury within each mechanistic subclass usually require operative fixation. The Tile classification stratifies the injury first by resulting stability, i.e. stable (A), rotationally unstable only (B), and vertically and rotationally unstable (C), and then subclassifies by pattern of injury (Table 96-1). Type B and C injuries usually require operative fixation. Both these commonly used classification systems have their merit, in that they communicate information about the pattern of injury, functional stability, and appropriate treatment.

Acetabular fractures are not uncommon in association with pelvic fractures. For the most part, they are also associated with similar visceral injuries as pelvic fractures. The classification system is descriptive in nature and also can be used to predict concomitant injuries; however, this is beyond the scope of this book.

Clinical Assessment

A pelvic ring injury should be suspected if there is any visible swelling, ecchymosis, or compound wounds around the pelvis. Scrotal or labial swelling and ecchymosis, i.e., bleeding from the urethral meatus, vagina, or rectum, are also good clinical signs of pelvic injury. Obvious rotational deformity or shortening of the lower extremities also may be indicative of injury.

The pelvis should then be assessed by manual palpation of tenderness anywhere around the pelvic ring. Next, the clinical stability should be tested by anterior compression of the pelvis at the anterosuperior iliac spines, followed by lateral compression of the iliac wings. Any gross motion that is felt indicates an unstable pelvic ring injury.

The peripheral pulses should be palpated, and a detailed neurologic examination of the lower extremities should be recorded to document the baseline function and to determine whether a peripheral nerve versus nerve root is involved in the injury.

Radiographic Assessment

The routine anteroposterior (AP) pelvis film obtained during the advanced trauma life support (ATLS) resuscitation is adequate to correctly identify 90% of pelvic ring injuries.7 Virtually any clinically relevant pelvic instability can be identified. Indicators of instability include greater than 5 mm of displacement of the posterior elements in any plane and greater than 2.5 cm of widening of the pubic symphysis, avulsion fractures of the ischial spines or tuberosities, and avulsion fractures of the L5 transverse process. Additional inlet and outlet radiographs are helpful to assess AP displacement and superior migration of the hemipelvis, respectively.

For sacral fractures and subtle sacroiliac joint disruptions, the CT scan can further delineate fracture displacement.

Management

The most important aspect of management of the patient with a pelvic ring injury is the resuscitation as per the ATLS protocol.8 During the circulatory assessment, the presence of other thoracic, abdominal, or extremity sources of blood loss should be ruled out. Massive fluid replacement, including transfusions, may be necessary.

Initial stabilization of the pelvis is important to minimize or decrease bleeding from the pelvis and to stabilize intrapelvic vascular clots.9,10 Historically, military antishock trousers (MAST) were used for this, but they have been found to contribute to decreased ventilatory ability and lower extremity compartment syndrome.11 Recently, it has been found that simply wrapping and tying a sheet around the pelvis can effectively provide initial provisional stability.12 A simple two-pin anterior external fixator or the pelvic C-clamp can be applied quickly to the anterior pelvis in the emergency room and provide adequate stability. Caution should be exercised in using the pelvic C-clamp posteriorly because improper pin placement can easily result in visceral, neurologic, or arterial injury. There is a greater margin of safety if the technique is applied using fluoroscopic assistance.13,14

The next priority is the identification and treatment of all significant sources of bleeding. If the patient is responding to the fluid resuscitation and becomes hemodynamically stable, other imaging, such as contrast-enhanced CT scanning, can be used to further delineate other sources of blood loss. Angiography for pelvic bleeding is indicated if there is ongoing unaccountable blood loss after provisional stabilization of the pelvis with an external fixator. It has been shown to be an effective way to rule out and treat arterial sources of hemorrhage in the pelvis.15,16

In the face of exsanguinating hemorrhage from venous pelvic bleeding not controllable by obtaining mechanical stability, open packing of the pelvis may be considered as a last resort; however, mortality rates are extremely high.

Provisional stabilization while the patient is being optimized in the ICU includes external fixation for unstable injuries, as well as skeletal traction on the lower extremity if there is associated vertical instability of the pelvis.17

Definitive stabilization usually requires internal fixation, provided there are no contraindications to surgery. The ideal time for this is when the patient is stable and systemically optimized. Fixation usually includes SI screws for posterior injuries18 and open reduction and internal fixation or percutaneous screws for anterior injuries (Fig. 96-4). The use of external fixation and traction for routine injuries treatable with open reduction and internal fixation is not advised19,20 because this usually compromises mobilization of the patient and increases the risk of associated problems of prolonged bed rest, including pneumonia, venous thromboembolism, and decubitus skin ulceration, as well as an increased mortality rate.

Complications

Other complications may arise as a direct result of the pelvic ring injury. Massive blood loss and hemodynamic instability as described earlier are the most acute issues to be managed. Injuries to the gastrointestinal and urologic systems, vaginal tears, and skin degloving can cause significant problems if not managed properly in the acute setting.

Laceration of the colon or rectum results in fecal contamination of the peritoneal and retroperitoneal space. If left untreated, this results in abdominal or pelvic sepsis. The clinical diagnosis can be made with the finding of blood per rectum or on rectal examination. Rectal tears also can be palpated in the digital rectal examination and visualized by flexible proctosigmoidoscopy. Treatment consists of provisional external fixation of the pelvis, laparotomy with defunctioning colostomy, wide drainage and irrigation of the perirectal space, and repeated débridements until the pelvis and abdomen are clean. Definitive internal fixation may be considered at this time.

Injuries to the bladder and urethra are also very common, especially with high-grade anteroposterior compression or vertical shear injuries. The physical findings of blood at the urethral meatus and high-riding or mobile prostate with perineal ecchymosis suggest the diagnosis. This is confirmed with a retrograde urethrogram. Intraperitoneal bladder rupture should be repaired, whereas extraperitoneal ruptures may be treated by drainage only. Urethral tears should be stented, if possible, by a catheter. A defunctioning suprapubic catheter followed by delayed repair may be necessary with complete or complicated urethral tears. Once it is ensured that the pelvic contents are sterile, internal fixation of the pelvis may follow.

A laceration of the vagina should be suspected if there is blood in the perineum. This can occur with pelvic ring injuries with greater degree of displacement anteriorly. A bimanual and culposcopic examination to palpate and visualize the tear will confirm this. In general, these lacerations may be débrided and repaired and usually do not require a laparotomy. Timely repair has been seen to decrease the incidence of pelvic abscesses and infection.21

The soft tissue envelope around the pelvis is contused frequently; any laceration should be considered a possible open wound communicating with the pelvic ring injury. The Morel-Lavallee lesion is a closed lateral skin degloving injury that occurs most commonly with lateral compression injuries. This is apparent clinically by a large subcutaneous hematoma and lateral pelvic ecchymosis. There is an increased risk of cellulitis, as well as deep wound infection. They should be treated as open wounds, with serial débridements as necessary.22

The patient with a pelvic ring injury is at high risk of developing a deep vein thrombosis (DVT) owing to the injury itself, the often-accompanying lower extremity injury, immobilization, and altered coagulation profile secondary to transfusions of blood products. Prophylaxis is required, both mechanically and pharmacologically, in the absence of contraindications. Mechanical methods include intermittent pneumatic compression devices and graduated compression stockings if there are no extremity injuries that prevent the application of these devices. Pharmacologic prophylaxis, such as subcutaneous low-molecular-weight heparin, should be administered routinely, except when contraindicated by active bleeding or intracranial neurologic injury. The presence of a DVT in the lower extremities can be detected by venous duplex ultrasound. Intrapelvic DVTs are best detected by venography or magnetic resonance angiography; ultrasound is not a reliable modality in this situation.23 There is a very high rate of embolism of intrapelvic clots; therefore, treatment is imperative. If anticoagulation is contraindicated owing to ongoing bleeding or upcoming major surgery, an inferior vena cava filter should be placed.

Extremity trauma is very common, occurring in up to 75% of patients with multisystem and pelvic ring injuries.1 Established patterns of injury are seen with common mechanisms, such as head-on and side-impact motor vehicle collisions, a pedestrian struck by a vehicle, and falls from a height. The extremity injuries include injuries to the bones, joints, soft tissues, vascular system, and peripheral nerves.

Head-on motor vehicle collisions often result in a closed head injury, flexion-distraction injuries of the spine, intraabdominal injuries, posterior element acetabular fractures, hip fracture dislocations, bilateral femur and tibia fractures, and posterior knee dislocation with associated popliteal artery injury. Lateral-impact collisions and pedestrian injuries also have their own distinct patterns. Falls from a height frequently result in head injury; thoracic vascular shear injuries; abdominal visceral lacerations; spinal burst fractures; vertical shear injuries of the pelvis; and lower extremity fractures, including femoral neck and shaft fractures; tibial plateau, shaft, and pilon fractures; and calcaneal fractures. Although every patient should be examined thoroughly for all injuries, these patterns help to direct the focus of assessment to the most likely areas of injury.

Fracture Assessment

In general, all fractures need to be assessed for specific findings aside from the underlying fracture or dislocation. Excessive bleeding from fractures or vascular, neurologic, and soft tissue envelope injuries should be assessed, as well as the presence of compartment syndrome and open fractures.

Subtle injuries require palpation of each bone and motion of each joint. Even then, serial examinations several days after the initial injury may be required to detect all injuries. Any suspected areas should be imaged with radiographs in orthogonal planes.

Open fractures are graded by the system of Gustilo and Anderson24,25 (Table 96-2).

Treatment

Although the initial fracture care usually is done in the emergency department, occasionally patients will be admitted to the ICU before any treatment can be initiated. After the initial assessment, any wounds should be flushed with saline and covered with a sterile dressing. Gross limb deformity and joint dislocations should be reduced and splinted and the neurovascular examination repeated. All musculoskeletal injuries should be imaged, and repeat fracture reductions or reductions of dislocations may be performed at this time as necessary. The patient should be prepared for operative intervention if a vascular injury, open fracture, irreducible dislocation, or compartment syndrome is detected.

In the case of open fractures, intravenous antibiotics should be administered, with gram-positive coverage for all compound fractures and with the addition of gram-negative and anaerobic coverage for contaminated wounds. The patient's tetanus status should be determined, and tetanus toxoid and immunoglobulin should be administered as required (Table 96-3).

All compound fractures should be treated with urgent irrigation and débridement within 8 hours, followed by provisional or definitive fixation, depending on the condition of the soft tissue envelope and the amount of wound contamination. Gustilo-Anderson type I, II, and IIIA fractures can be treated with irrigation and débridement and immediate definitive fixation, followed by serial débridements every 48 hours until the wound is clean. Type IIIB injuries usually require provisional external fixation and serial débridements until the wound is clean enough for definitive fixation and soft tissue coverage. For type IIIC injuries, the most pressing concern initially is reestablishment of perfusion to the extremity. After provisional fixation and vascular repair, serial débridements again may be required before definitive fixation can be performed, with soft tissue coverage as necessary. Prophylactic fasciotomies are frequently required to prevent reperfusion compartment syndrome. There is an increased risk of infection and nonunion with increasing grade of injury.

If the patient has not been optimized or there is some other delay postponing definitive treatment, provisional treatment of the fractures by splints, traction, or external fixation may be necessary. In addition, prophylaxis for DVT should be initiated, as discussed earlier. Attention to the skin, especially in dependent areas such as the sacrum, heels, and posterior scalp, should be maintained, with frequent log-rolling and skin care to avoid the development of decubitus ulcers.

Definitive fixation of most fractures allows greater ease of mobilization for general care and pulmonary toilet. Early mobilization and physical therapy also prevent the development of joint contractures and muscle atrophy, resulting in a faster recovery and reduced morbidity. DVT prophylaxis should be maintained during the postoperative period until the patient is mobilizing well independently.

Complications

Blood loss from fractures alone can be enough to cause hemodynamic instability. Even without a significant arterial laceration, femur fractures can result in blood loss of up to 2 units, tibia fractures 1 unit, and pelvic and acetabular fractures 4 units or more. Aggressive fluid resuscitation must be maintained while reassessing for other causes of hemodynamic instability. With increasing swelling of the extremities from fracture bleeding, there must be a high index of suspicion for compartment syndrome.

Vascular Injury

The vascular status of each limb must be assessed by checking for the presence and quality of peripheral pulses, as well as the perfusion of the tissues distal to the zone of injury. Blunt or nonpenetrating vascular injuries often are associated with traction or avulsion injuries, fractures, and dislocations. It is important to assess the entire peripheral vasculature if there are multiple ipsilateral injuries, such as concomitant femur and tibia fractures. Knee dislocations and tibia fractures have the highest incidence of arterial injury, followed by femur fractures and traction injuries to the shoulder girdle. An abnormal vascular examination may be due to vascular spasm, external compression, intimal tear, or disruption of the artery itself. If the vascular examination is abnormal before or after gross realignment of fractures and reduction of dislocations, further investigation with an ankle-brachial index, angiogram, or magnetic resonance angiography is indicated to determine the nature of the injury. External compression of the artery usually can be relieved by reduction of the fracture or dislocation, and vascular spasm usually resolves after reduction as well.

Penetrating injuries such as gunshot and knife wounds also have a high incidence of vascular injury. All structures in the path of the projectile should be assessed from entry to exit wounds, including a generous surrounding area of collateral damage.

If the limb remains dysvascular, urgent operative intervention is required because muscle necrosis begins after 6 hours of warm ischemic time.26 The sequence of events for vascular repair usually begins with provisional fracture stabilization with an external fixator or rapid internal fixation followed by the establishment of a provisional shunt to restore perfusion.27 Definitive vascular repair, ideally with an end-to-end anastamosis or saphenous vein graft, if necessary, then can be performed, followed by definitive fracture fixation.26 Reperfusion edema and compartment syndrome are common; thus a prophylactic fasciotomy usually is indicated. Wound coverage by skin graft or free flap can be achieved after the wound has undergone serial débridements to minimize the risk of wound infection and sloughing of the graft28 (Fig. 96-4).

Neurologic Injury

If the patient is awake and cooperative, a detailed neurologic examination of each extremity should be done, with particular attention distal to the zone of injury. If the patient cannot participate in the examination, general observations of gross limb movements and reaction to pain stimulus help to establish baseline function. Most peripheral nerve injuries are neuropraxias, which begin to recover spontaneously over 6 to 12 weeks. The progress of recovery can be monitored with serial nerve conduction studies. In the situation of penetrating injuries or dissection for open reduction and internal fixation of fractures, the nerve may be explored to assess for injury. If it is found to be lacerated, direct primary repair is indicated once the wound is clean.29

With or without nerve repair, it is important to splint the extremity in a functional position of rest, with occupational and physical therapy involvement to maintain motion of the affected joints. Muscle stimulators also may be beneficial to decrease the rate of atrophy of the affected muscles. If acute repair or grafting has been performed, the extremity should be splinted in a resting position temporarily (1 to 2 weeks) to allow the repair to begin to heal and then gradually mobilized to prevent arthrofibrosis and contractures.

Compartment Syndrome

Increased compartment pressures result from intercompartmental edema and bleeding associated with fractures or vascular injury. The increase in pressure causes a compressive occlusion of capillary venules, stopping capillary flow and perfusion of tissues, the most sensitive of which are the muscles and nerves. Because the compressive phenomenon affects the microvasculature, distal pulses usually are maintained during this process.30

Clinically, compartment syndrome is manifested by the “five P's”. In order of clinical relevance, these are pain out of proportion to the injury,31 pain with passive stretching of the affected muscles, paresthesia (numbness) involving the nerves within and distal to the compartment, powerlessness (weakness) of the muscles within the compartment, and a pulseless extremity (which may not necessarily ever happen). If left untreated, the muscles and nerves undergo necrosis, resulting in ischemic contractures and loss of sensation or painful paresthesias, leaving the limb with very poor function.

The most common sites affected are the lower leg, in association with tibia fractures, and the forearm, in association with radius and ulna fractures. Compartment syndrome also can occur in the thigh, buttock, upper arm, hand, and foot.32,33

Early recognition is mandatory either clinically, as described earlier, or by compartment pressure monitoring. A compartment pressure greater than 30 mm Hg or within 30 mm Hg of the diastolic pressure is diagnostic for compartment syndrome. It may be necessary to rely on pressure monitoring if the patient is obtunded, there are significant distracting injuries, or the clinical examination is unreliable (psychiatric conditions, intoxication, etc).

The initial treatment includes elevation of the limb to the level of the heart and release of all circumferential or compressive dressings. If there has been no improvement within 1 hour, a fasciotomy is required. If in doubt, it is far better to perform a fasciotomy because the consequences of untreated compartment syndrome are extremely debilitating and usually permanent. Owing to the typical amount of swelling with these injuries, the wound usually cannot be closed and requires coverage with a skin graft several days after release.34

Fat Embolism Syndrome

Fat embolism syndrome (FES) encompasses the respiratory, neurologic, and other systemic sequelae of the embolism of fat from the marrow space of long bones. It occurs in up to 2% of isolated long bone fractures and up to 10% of multiply injured patients. The most significant feature of FES is the potentially severe respiratory effects, which may result in adult respiratory distress syndrome (see Chap. 27). It usually occurs within 1 to 3 days following injury, and the clinical presentation includes the following: lethargy, disorientation, and irritability with the appearance of petechiae on the trunk and in the axillary folds, conjunctiva, and fundi in 50% of cases. Blood tests may demonstrate anemia and thrombocytopenia, and examination of the urine may show lipiduria.

The diagnosis of FES can be made on major and minor criteria. The major criteria include respiratory insufficiency, central neurologic impairment, and petechial rash. The minor criteria include tachycardia, fever, retinal fat emboli, lipiduria, anemia, and thrombocytopenia.35

Once the patient becomes hypoxemic, supportive measures are all that can be done, including positive end-expiratory pressure (PEEP) and lung-protective ventilation. The most significant treatment aspect of FES is prevention. Early long bone fracture fixation has been shown to be a key factor,36 particularly with tibia and femur fractures. Aggressively fluid resuscitation and maintaining an adequate circulatory volume also have been shown to be protective. Despite aggressive management, the mortality rate of full-blown FES is up to 15%; thus the importance of early fracture fixation is critical.