Pelvic Trauma

Authors: LaMont C. Smith, MD, Attending Physician and Clinical Instructor, Department of Surgery, Division of Surgical Critical Care, R. Adams Cowley Shock Trauma Center, Division of Emergency Medicine, University of Maryland Medical System, Baltimore; and Thomas M. Scalea, MD, Physician in Chief, R. Adams Cowley Shock Trauma Center; Division of Emergency Medicine, University of Maryland Medical System, Baltimore

Peer Reviewer: O. John Ma, MD, Professor and Vice Chair, Department of Emergency Medicine, University of Missouri-Kansas City School of Medicine, Kansas City, Missouri

Emergency department (ED) physicians frequently are required to assess and stabilize multiple trauma patients. Following the initial stabilization of the patient's airway and circulatory status, secondary potential life-threatening injuries should be identified and addressed.

Pelvic injuries may occur secondary to blunt or penetrating trauma and may result in stable or life-threatening injury patterns. Patients with pelvic trauma require a thorough evaluation for associated injuries and careful monitoring for potential deteriorations.

Therapeutic options continue to advance and evolve as alternative modalities are explored. The authors review the early recognition, stabilization, and management of a patient with a pelvic fracture.

— The Editor

Introduction

Although pelvic injury can be the result of either penetrating or blunt force injury, the majority of pelvic trauma cases involve blunt force. Pelvic fracture management is perhaps the best example of multidisciplinary care because patients often require therapy—in addition to bony stabilization—for associated system injury including neurologic, urologic, and vascular injuries. Although the initial patient focus should be rapid hemodynamic stabilization followed by complete radiologic survey to determine the severity of the injury and associated injuries, upper level interventions (e.g., angiographic embolization) may be necessary. Both general and orthopedic surgery expertise may be necessary to provide optimal care. It is also important to determine whether transfer to a higher level of care is necessary early in the patient's course.

Patients with penetrating pelvic trauma, although they have the potential for similar organ injury as those with blunt trauma, are more likely to sustain intra-abdominal injury. Penetrating pelvic injury should be suspected with any gunshot or stab wound that involves the flank, buttock, or lower back and paravertebral region. Patients who present in shock require immediate surgical exploration. Those patients who are stable can be evaluated with a series of radiographs and potentially treated nonoperatively.

Blunt Pelvic Injury

Epidemiology. More than 60% of pelvic fractures are the result of vehicular trauma, either vehicular crashes or struck pedestrians; falls from a height account for an additional 30%.1 The remainder generally occur from industrial or recreational injury. Low impact injuries may produce stable isolated fractures (e.g., an isolated pubic rami fracture). High impact injuries often produce gross instability of the pelvic ring with concomitant soft-tissue injury and life-threatening hemorrhage.

The mortality from pelvic fractures ranges from 6% to 20%, but may reach 50% when associated with significant hemorrhage and hypotension.2 Shock on arrival and age more than 60 years have been shown to be associated with increased mortality.3,4 A base excess (≥ -5) at the time of patient presentation also has been shown to be associated with increased mortality.5 While death can occur directly from pelvic hemorrhage, more often it is the result of concomitant injuries.6 The mortality rate from open pelvic fractures can be as high as 30-50%, also often from associated injuries.7 Older patients tend to have a more protracted and complicated course, probably secondary to chronic medical problems and lack of physiologic reserves. Older patients also tend to have a worse outcome, are more likely to bleed, and may require angiography for relatively minor fractures.8

Anatomy of the Pelvis. The pelvis consists of two innominate bones and the sacrum. Each innominate bone consists of an the ilium, pubis, and ischium. The pubic bones are the thinnest of the pelvic bones and often are fractured in pelvic trauma. Their fragments may injure the bladder, urethra, or vagina.9 Several strong posterior ligaments, as well as the sacroiliac joint, give the pelvis its stability. The two most important ligaments are the sacrotuberous ligaments, which extend from the sides of the sacrum to the iliac tuberosities; and the sacrospinous ligaments, which pass from the sides of the sacrum to the ischial spines.

There are four pelvic joints. The symphysis pubis is a slightly movable anterior joint that connects the two pubic bones. The sacroiliac (SI) joints, which are the strongest joints in the body, are formed where the ilium joins with the first two sacral vertebrae and connect the spine to the pelvis. These joints gain additional strength from the anterior and posterior ligaments; although rarely involved in pelvic fractures, when disrupted, the pelvis almost invariably is unstable. The sacrococcygeal joint is a hinge joint between the sacrum and the coccyx.

Muscles of note that attach to the pelvis include the sartorious, which inserts on the anterior superior iliac spine; the rectus femoris, which inserts on the anterior inferior iliac spine; and the hamstrings, which attach to the ischial tuberosities. Avulsion fractures sometimes occur at these sites.10 Posterior fractures of the pelvis more commonly are associated with neurovascular structural damage and can affect weight-bearing activities. Anterior fractures are more likely to cause urogenital damage and usually do not affect weight-bearing activities.

The acetabulum articulates with the femoral head to make the hip joint. These two bones fit together like a ball and cup; there is free rotation of the femoral head. The anterior column of the acetabulum is formed by the pubic ramus and the anterior rim. The posterior column comprises the ischial tuberosity and the posterior rim of the acetabulum. The dome is especially important in weight-bearing activities.

Classification of Pelvic Fractures

Several different classifications of pelvic fractures exist, but all emphasize the underlying stability or instability of the pelvis. High-risk pelvic fractures are those with symphysis diastasis more than 2.5 cm, involvement of all four rami, widening of the SI joint more than 0.5 cm, or vertical shear. A stable fracture is one that will not undergo rotational or vertical deformation when subjected to normal physiologic loads. An unstable fracture is one in which movement —rotational, vertical, or both—can occur in the three-dimensional plane when normal forces are applied.

Morphologic Classification: The Kane Modification of the Key and Conwell Classification. This system is based upon radiographic assessment of the bony components involved and the number of breaks identified.

Type I. These are isolated disruptions of pelvic bone and do not involve the pelvic ring (e.g., fractures of single pubic ramus, iliac wing, sacrum, and avulsion fractures). The pelvic ring is intact, and these stable fractures generally heal rapidly. Avulsion fractures and those suggesting a single break in the ring are usually the result of less kinetic energy transfer, and hence have fewer sequelae.11 These fractures may involve the anterior superior iliac spine, anterior inferior iliac spine, or the ischial tuberosities. Avulsion injuries of the anterior superior iliac spine or ischial tuberosities most commonly are seen in teenagers who have sustained an injury while participating in vigorous running or dancing. These fractures generally are treated conservatively with bed rest and gradual ambulation.

Type II. These are single fractures of the pelvic ring without displacement. These fractures commonly involve the pubis or sacroiliac (SI) joint, which are relatively mobile joints, allowing a single break to occur. These are stable fractures that are treated conservatively with bed rest. However, 25% of these patients will have a major soft-tissue injury and/or hemorrhage.11 If displacement of the fracture fragment is found, a second break in the ring usually exists.

Type III. These involve double fractures of the pelvic ring. These are unstable fractures resulting from high-energy pelvic trauma and often are associated with life-threatening injuries. Examples include straddle fractures, open book fractures, bucket handle fractures, Malgaine fractures, and pelvic dislocations.

A Malgaine fracture is a fracture of the pubis and ischium associated with a vertical shear fracture of the ipsilateral ilium, fracture/dislocation of the sacroiliac joint, or a vertical fracture of the sacrum. This is an extremely unstable pelvis, often associated with leg shortening. There is rupture of the entire pelvic floor, and this fracture is rotationally and vertically unstable. It usually results from a fall from a height onto lower limbs. Approximately 20% of all patients who sustain a fatal injury in a motor vehicle crash also have a Malgaine fracture.12

Type IV. These involve a fracture of the acetabulum (Figure 1). Although these fractures only account for 5% of all pelvic fractures, they may affect weight-bearing activities.11 Fractures can alter the integrity of the anterior or posterior column or the dome of the acetabular cavity.

Figure 1. Acetabular Fracture

Classification by Mechanism of Injury. The Young and Burgess Classification. This classification system has good predictive value of mortality and morbidity by incorporating an appreciation of the causative forces and resulting injury patterns.13

Lateral Compression (LC) Fractures I, II, III. Lateral compression is the most common type of pelvic fracture (about 60% of injuries) and has an associated 6.6% mortality.13 Force is applied to one side of the pelvis (e.g., when a patient is "t-boned" in a motor vehicle crash). With these injuries the pelvic ring implodes or collapses; one side rotates medially toward and sometimes beyond the midline, usually on a posteriorly based perpendicular axis. Usually, the sacrotuberous and sacrospinous ligaments are intact. While bleeding is less common, LC fractures more often are associated with life-threatening torso injury. Thirty percent of these patients present in shock, usually from extra pelvic bleeding, and 20% develop adult respiratory distress syndrome (ARDS) with its associated high mortality rate.13-15

Anterior-Posterior Compression (APC) Fractures. In these fractures, force is applied directly to the pubis (e.g., when a pedestrian is struck frontally by a car). These fractures compose 15% of pelvic fractures and have an associated mortality of approximately 20%. They are associated with the largest amount of blood loss. Sixty percent of these patients present in shock, and 20% develop ARDS.13-15

Unclassified Injuries. Open fractures: These often occur with motorcycle accidents and struck pedestrians. An open fracture occurs when there is communication between the pelvic fracture and a laceration or puncture of the skin, vagina, bowel, or rectum. These are associated with a mortality rate as high as 50% from massive hemorrhage, major vessel injury, and sepsis. Controlling hemorrhage with wound packing, MAST trousers, or angiography can reduce the mortality rate to below 10%.16 Many of these patients will require a colostomy. Principles of care include rapid control of bleeding, fecal diversion, and wide local debridement of nonviable tissue. Straddle injury: This injury usually causes fractures of bilateral pubic rami and often is the result of a high-speed motorcycle accident or a fall from great height. Genitourinary and renal damage are common.

Associated Injuries. In pelvic fractures and high-energy injuries, many patients have associated injuries. (See Table 1.)

Table 1. Associated Injuries

The high association of multisystem injury in patients with pelvic fractures should lead to a thorough evaluation of all organ systems based on injury mechanism, patient history, and current examination of the patient. A computed tomography (CT) head scan should have a high priority in patients with altered level of consciousness; patients with the possibility for an associated long-bone fracture should undergo focused appropriate imaging, remembering that patients with associated brain injury may be unable to identify sites of pain. Serial examinations are also an important tool to identify potential areas of injury.

Significant thoracic trauma also is associated with pelvic fractures, and the patient should be evaluated for pneumothoraces, or hemothoraces and blunt aortic injury. Aortic injury is most common in patients with lateral compression mechanisms. Initially, a chest radiograph is used to identify obvious abnormalities or findings that are significant for more serious underlying injury. Spiral CT can be used to obtain more detailed imaging. In patients who require immediate operative intervention for life-threatening hemorrhage, transesophageal echocardiography can be quite helpful for aortic injury.

Intra-abdominal injuries often accompany pelvic fractures and may involve the liver, spleen, or mesentery. The reported incidence of diaphragmatic injuries is relatively low, but the statistics may be badly under reported because the diagnosis can be missed. The perineum should be examined carefully on the secondary survey for vaginal and/or perirectal laceration, signifying an open pelvic fracture. These injuries must be dealt with expeditiously to avoid the complications of retroperitoneal sepsis.

Urinary tract injuries are common, especially with displaced pelvic fractures. With major pelvic injuries, it is safe to assume a urinary tract injury exists until proven otherwise. Urethral injuries are twice as common as bladder injuries and are the most common lower urinary tract injuries associated with pelvic fractures. Signs include gross hematuria, blood at the meatus, a high-riding prostate, and scrotal ecchymosis. The high-riding prostate is the result of shearing of the prostate from the pelvis with subsequent migration superiorly and a hematoma filling the normal position of the prostate. If there is no meatal blood and the rectal examination is normal, then a gentle attempt at Foley catheter placement may be tried. If any resistance is encountered, assume a urethral injury exists and consult urology for suprapubic cystostomy.17 Male patients should have a retrograde urethrogram before a Foley catheter is placed if there is blood at the meatus.

The most common associated lower urinary tract injury in the male is a posterior urethral tear and should be suspected in any patient who presents with gross hematuria and a pelvic injury.17

Anterior urethral tears commonly are associated with straddle injuries, but actually occur infrequently.

Bladder contusions are the least serious bladder injury. They are common and usually resolve without complications. They result from an incomplete tear of the bladder mucosa and usually are treated with short-term bed rest until hematuria resolves. Bladder rupture occurs in about 5-8% of pelvic fractures.19 A full bladder usually will rupture at the dome, which is the weakest part of the bladder wall and the only part of the adult bladder covered by peritoneum. Intraperitoneal bladder ruptures are more commonly the result of seat belt compression of a full bladder, representing 20-40% of traumatic bladder ruptures.19 An intraperitoneal bladder rupture requires surgical repair because of the risk of associated chemical peritonitis. It is diagnosed via retrograde cystogram (voiding cystourethrography).

An empty bladder usually will not rupture but may be lacerated by a bony fragment producing an extra-peritoneal rupture; 50-80% of bladder ruptures associated with pelvic fracture are extraperitoneal and usually occur near the base of the bladder.19 The mechanism is believed to be a burst injury or the shearing force of the deformed pelvic ring. The pelvic fracture itself usually does not cause the bladder perforation. The bladder must be distended fully during the evaluation, and a post-void film is done. The post-void film is important because posterior tears may not be evident in a simple anterior-posterior film; 10% of bladder ruptures are detected only on post-drainage films.19 Some practitioners advocate the use of a CT cystogram as a more sensitive detector of small bladder rupture as well as soft-tissue injury. A cystogram of an extraperitoneal bladder rupture may show extravasation around the base of the bladder and may extend into the thigh and penis; these injuries usually are treated with only Foley catheter drainage.

Combined intraperitoneal and extraperitoneal bladder injuries occur in approximately 10% of bladder ruptures. The mortality rate for combined injuries approaches 60%, owing to the severity of concomitant injuries.19 Penetrating pelvic trauma also can result in bladder injuries. There is a high association with intra-abdominal injury with penetrating trauma, and surgical exploration often is mandated. The cystogram may be negative in patients with small caliber bullet wounds; these injuries sometimes are diagnosed only at exploratory laparotomy.

Initial Management

The priority for a patient with a significant pelvic injury is the same as any trauma patient with multisystem injury. Immediate airway control is critical and endotracheal intubation should be performed in any patient in extremis or in whom there is a suspicion of significant pelvic trauma. Endotracheal intubation will help facilitate the evaluation process and allow for adequate analgesia. The adequacy of oxygenation and ventilation should be monitored continuously, and an arterial blood gas (ABG) measurement can be extremely helpful.

Assessment of hemodynamic stability follows; some patients with significant blood loss will present with classic findings (e.g., hypotension and tachycardia); other younger patients may compensate for blood loss relatively well, so a high degree of suspicion is critical. A significant base deficit on arterial blood gas measurement is also a marker of volume depletion. Ongoing resuscitation to maintain stability also should be monitored and fluid totals carefully recorded; these patients almost always are bleeding, and a rapid search for the source is imperative.

Geriatric patients also represent a rapidly growing population with unique considerations and requirements. In addition to the presence of co-morbidities (e.g., diabetes, chronic obstructive pulmonary disease, and renal insufficiency), they are much more likely to develop multisystem organ disease during their hospitalization.

Because of the high incidence of multisystem trauma, patients with pelvic fractures may be unstable from other entities, in addition to pelvic fracture bleeding, and should be evaluated for tension pneumothorax, hemothorax, intra-abdominal injury, and bleeding from lower extremity fractures.

Caring for a patient with a pelvic fracture can be extraordinarily challenging. It is important to anticipate problems; these patients often have multiple injuries and can decompensate quite quickly.

Large bore intravenous access is mandatory in all patients with pelvic fractures. Every patient should have blood type and cross-matched and immediately available. In patients who are unstable, it is important to anticipate the need for coagulation factors (e.g., fresh frozen plasma and platelet packs). Hypothermia can be extremely problematic. It is wise to warm all fluids and blood early in the resuscitation. Finally, all patients with pelvic fractures must be assumed to have multiple injuries. The evaluation process must be rapid. It is important to anticipate the need for consultation and have all resources available when needed. The algorithms in Figures 2 and 3 may be useful in managing the pelvic trauma patient based upon the patient's level of hemodynamic stability.

Physical Examination

A careful physical examination is part of every trauma patient's evaluation and should be performed following the primary survey. In general, patients who have pelvic fractures will complain of pain. They may not complain of direct pelvic pain but often complain of lower abdominal pain, hip pain, or low back pain. Careful abdominal examination should be performed. Retroperitoneal injury, particularly if accompanied with significant blood loss, often will produce abdominal distension with tympany. The abdomen should be evaluated for bruising and tenderness.

The genitourinary tract should be examined with careful attention to identify blood at the urethral meatus in men, a sign of urethral disruption. In addition, suprapubic pain, tenderness, or the inability to void strongly suggests either a bladder or urethral injury; however, the ability to void does not rule out one. A careful rectal examination should be performed to evaluate rectal tone and the position of the prostate. A high-riding prostate also strongly suggests a urethral injury.

Lower extremities should be evaluated for concomitant fractures as well as their position. Some patients with significant posterior pelvic fractures often have unopposed motion of the ipsilateral psoas muscle, thus, that hemipelvis migrates cephalad and shortens the extremity. Careful neurologic examination should be performed with attention to the lower extremities. Patients with pelvic fractures may have lower extremity sensory or motor changes, some of which may be identifiable at the initial presentation.

The pelvis should be examined carefully. Rocking the pelvis is not considered to be an appropriate way to examine the pelvis. In addition to producing significant pain in patients with pelvic fractures, vigorous motion may cause recurrent bleeding in patients with unstable pelvic fractures. Thus, this maneuver should be avoided. Instead, the correct way to examine for pelvic stability is to gently attempt to compress the pelvis medially by squeezing the pelvis at the level of the iliac crest. If the pelvis is stable, there will be no motion. In patients with an unstable pelvis, there will be give with gentle manual compression.

The following physical findings may be helpful in patients with suspected pelvic fractures. Earle's sign is present when, on rectal examination, there is a large hematoma present or there is tenderness along the fracture line. A bony prominence also may be palpable. Destot's sign is a superficial hematoma seen above the inguinal ligament or on the scrotum. Roux's sign is present when the distance measured from the greater trochanter to the pubic spine is diminished on one side compared with the other. This finding suggests an overlying fracture of the anterior pelvic ring.

Laboratory Work

All patients with a suspected pelvic fracture should have routine chemistries and a complete blood count performed. The urine should be examined for gross or microscopic hematuria. The majority of patients with a bladder injury will have gross or microscopic hematuria; however, 5% will have a normal urinalysis.19 ABG measurements are useful, especially early, to determine if there is a base deficit and the degree of acidosis. The serum lactate level also is useful as a measure of the adequacy of resuscitation. Coagulation profiles should be followed because patients with severe injury commonly develop coagulopathies.

Radiologic Evaluation

Plain Films. Every patient at risk for a pelvic fracture should be screened with an AP pelvic film. Patients who are hemodynamically stable, awake, and alert, who have no complaints of pelvic pain, and who are nontender on examination, do not require radiographic evaluation. However, any patient with a significant mechanism of injury and the potential for multitrauma, patients unable to provide a history, and those who are hemodynamically unstable, must be imaged.

The pelvic radiograph must be examined carefully for evidence of fracture. A systematic approach will minimize missed fractures. Initially, we should ignore the pelvic bones and evaluate the soft tissue for signs of inflammation or foreign bodies. The next step is to examine the lumbar spine for evidence of fracture and the femoral head and neck for signs of injury. Finally, the pelvis itself should be examined. It is useful to start with the three big circles that form the majority of the pelvis. The two circles that represent the superior and inferior rami should be examined for fracture or loss of continuity of the cortices, which will signify more subtle fractures. Finally, the circle that represents the pelvic inlet should be examined. Then, the SI joints should be examined for width and the sacral bone then examined. The arcuate lines of the sacrum should each be traced; this will identify subtle fractures. The iliac bones should be examined next, followed by each acetabular surface. It is important to trace both the anterior and posterior lip of the acetabulum to identify more subtle fractures.

It is also important to remember that the pelvis is a circle. It is difficult to break the pelvis in a single place. Virtually all pelvic fractures have at least two breaks. If one identifies a single pelvic fracture, a careful search for a second fracture is essential. In addition, plain films can underestimate both the number and severity of pelvic fractures. This fact is particularly evident in the posterior elements. The gastrointestinal tract may obscure subtle fractures. Even badly displaced posterior fractures may be difficult to see on plain x-ray because they are viewed only in a single projection.

Alternative views may be helpful. Inlet views place the radiographic beam at 45 degrees and shoot through the pelvis. These are most helpful in identifying sacral fractures or subtle anterior element fractures. Outlet views place the beam at 45 degrees with the beam sent through the anterior pelvis. These provide additional information about the sacrum at the SI joints. Judet views involve bumping the patient up and directing the beam at the acetabular surfaces and are very useful in identifying acetabular fractures.

CT Imaging. Abdominal and pelvic CT scans offer advantages in many patients who have sustained pelvic fractures. The ability to image the abdomen and pelvis simultaneously can be of great value. Clearly, CT imaging has become the gold standard imaging for blunt, solid, and hollow visceral injuries following blunt trauma. In addition, many patients who have pelvic fractures may have intra-abdominal injury without hemoperitoneum that will be missed with either ultrasound examination or diagnostic peritoneal lavage.

CT imaging also allows for better definition of pelvic fracture anatomy. Because CT images in three dimensions, it easily can define anterior-posterior displacement, which can be difficult to see on plain x-rays. Three-dimensional reconstructions can provide sophisticated images that will help define anatomy and operative fixation.

The final advantage of CT imaging is its ability to quantify intra-abdominal and retroperitoneal hemorrhage. Occasionally, patients with pelvic vascular injuries will have contrast blush or active extravasation at the time of the CT scan.

The disadvantage of CT imaging involves the time required and the small—but real—chance of IV contrast reaction. While CT imaging can be extremely helpful, it is contraindicated in patients who are hemodynamically unstable because the patient usually must be transferred out of the resuscitation area for the study. In this case, other methods of evaluation must be employed, or the patient must be stabilized before CT imaging is appropriate.

Treating Pelvic Fracture Bleeding

Treating pelvic fracture bleeding is a significant challenge. First, it is necessary to localize the pelvis as the source of blood loss. Other areas should be examined (e.g., the thorax and the abdomen). The general rule of thumb is that each major closed long-bone fracture results in a loss of several units of blood. When patients show signs of hemorrhage that cannot be ascribed to the chest, abdomen, or muscle compartments, pelvic fracture bleeding must be considered.

It can be very difficult to discern retroperitoneal hemorrhage from intra-abdominal hemorrhage on physical examination. Several modalities can be extremely helpful in rapidly assessing the abdomen for blood loss. Diagnostic peritoneal lavage (DPL) is a simple test that can be performed at the bedside. In patients with pelvic fractures, it is imperative to do this test using a supraumbilical open technique, which radically decreases the chances of inadvertently tapping any retroperitoneal hemorrhage.20, 21 Aspiration of 5 to 10 mL of gross blood generally is considered an indication for emergent laparotomy. Results from a recent study demonstrated that 84% of patients with grossly positive tap had life-threatening hemorrhage at the time of laparotomy.21 Decision making can be more difficult in cases where patients have a negative tap but bloody lavage fluid. False-positive lavage can result from diapedesis of red cells from retroperitoneal hemorrhage. DPL can be too sensitive, and small quantities of blood in the peritoneum may turn the lavage positive. This major risk is performing surgery on an insignificant intra-abdominal injury at the time the patient is exsanguinating from pelvic fracture bleeding.

Focused assessment with sonography for trauma (FAST) examination largely has replaced DPL in many trauma centers. FAST examination is portable and rapid and often can identify even small quantities of intraperitoneal fluid. It can be repeated if equivocal and should be able to identify large-volume hemorrhage in virtually every patient if the operator is skilled. In the hemodynamically unstable patient, it can be extraordinarily helpful in rapidly identifying free intraperitoneal fluid. If no free fluid is identified, then the focus for finding the source of hemorrhage may be directed toward the pelvic injury. While the amount of fluid necessary to turn a FAST examination positive may vary based upon body habitus, a FAST examination is usually positive with 200-300 mL of intra-abdominal blood.22,,23 Thus, hemodynamically unstable patients with a positive FAST examination almost certainly should undergo prompt laparotomy.

Methods of Hemodynamic Stabilization

External Compression. External compressive devices are considered the first-line therapy for treatment of pelvic fracture bleeding. External compression reduces the pelvic bony elements, restoring more normal pelvic anatomy. While this almost certainly will not stop major arterial bleeding, it can be helpful in tamponading venous bleeding or reducing blood loss from fracture fragments.24 A number of methods exist to achieve this result. Among the simplest is placement of a bed sheet under the patient with subsequent crisscrossing across the patient and then tying it down.25 While not elegant, it can be extremely effective and is perhaps most useful when transferring patients from rural EDs to a higher level of care.

The medical anti-shock trousers (MAST) garment was developed for use in the field. Although its role in patients with hypotension is debated, it can be quite helpful in patients with a pelvic fracture. The MAST garment acts as a pelvic splint and can reduce fracture fragments similar to the bed sheet with the advantage of pressure regulation, making this a more attractive alternative. It may be particularly effective when transporting patients within the hospital; keeping the fracture fragments stable reduces the blood loss that so often is associated with patient movement (e.g., from the stretcher to the bed).26 Disadvantages of using the MAST garment include a potential for increased intra-abdominal as well as intrathoracic pressure, difficulty with oxygenation and ventilation, renal dysfunction, and limb ischemia.

A number of pelvic clamps have been devised that can compress the posterior fragments of a pelvic fracture. The disadvantage of the pelvic clamps is that they require significant expertise, and general anesthesia frequently is required to place them. The advantages include good reduction of the posterior pelvic elements and the ability to be adjusted to give better access to the groin or abdomen for angiography or laparotomy.

One of the greatest advances recently has been the development of the pelvic binder. The pelvic binder acts similarly to the bed sheet, putting even pressure on the pelvis. The binder can be placed and, then, adjusted using the Velcro straps. This simple device can dramatically reduce displaced fracture fragments. Its advantages are its ease and rapidity of use. However, it must be adjusted to obtain access to the groin or anterior abdominal wall.

External fixation offers a number of advantages in patients with skeletally unstable fractures. The skeletal rigidity provided by an external fixator is probably superior to all other methods, except the posterior pelvic clamp. The external fixator can provide definitive stabilization in some patients with pelvic fractures. In some level I or II trauma centers where orthopedic expertise is immediately available, the external fixator can be applied immediately. Similar to the MAST or pelvic clamps, external fixation almost certainly helps tamponade bleeding from bony fragments and by reducing pelvic volume, it almost certainly stops venous bleeding as well. The external fixator can be adjusted to give access to the abdomen for laparotomy or to the groin for angiography.

Angiography and Selective Embolization. Angiography has the ability to precisely define a pelvic vascular injury. In addition, transcatheter embolization can provide definitive hemostasis in patients with pelvic fractures.27 Embolization has been demonstrated to be both safe and effective in obtaining pelvic hemostasis.28,29

Identifying patients in need of embolization can be difficult. It is wise to have a pre-established limit on the amount of blood transfused for pelvic bleeding to rapidly identify patients who may benefit from embolization.

The Eastern Association for the Surgery of Trauma suggests the following guidelines for angiography: 1) patients with major pelvic fracture who have signs of ongoing bleeding after nonpelvic sources have been ruled out; 2) patients with major pelvic fracture who are found to have bleeding in the pelvis who cannot be controlled adequately at the time of laparotomy; and 3) patients with evidence of arterial extravasation of intravenous contrast in the pelvis by CT imaging.25

Our institutional indications for angiography are: 1) patients with pelvic fracture with ongoing hypotension and a negative FAST examination; 2) larger expanding hematoma seen at the time of laparotomy; 3) more than four units of blood for pelvic fracture bleeding in 24 hours; 4) more than six units of blood for pelvic fracture bleeding in 48 hours, and 5) evidence of vascular injury seen on CT imaging.

Diagnostic angiography should involve a flush aortogram first, which may identify very large pelvic vascular injuries, allowing the angiographer to deal with them expeditiously. In addition, aortography may identify other injuries (e.g., concomitant lumbar artery injuries). Once the arterial injury is identified, it can be embolized with a number of substances (e.g., polystyrene spheres, wire coils, or hemostatic gelatin sponges).29 Ideally, one would like to occlude the blood vessel at its point of bleeding but not flush hemostatic material distally. Dual embolization potentially increases complications such as impotency or perineal ischemia. Contrast studies of the genitourinary tract should be delayed until after angiography is completed. If positive, contrast extravasation of the pelvis may limit the ability of the angiographer to identify pelvic vascular injuries. Independent predictors of finding bleeding on angiography include: 1) age more than 55 years; 2) absence of long bone fractures; and 3) emergent angiography.29

Direct Operative Control of Pelvic and/or Abdominal Hemorrhage. Many patients with pelvic fractures have concomitant intra-abdominal injuries that are best treated with operative control. It is tempting, then, to attempt direct operative control of the pelvic fracture bleeding; in the majority of situations this is unwise. The main hypogastric vessel artery is extremely short and sequences into a large number of vessels deep in the pelvis. It can be extraordinarily difficult to identify the precise source of bleeding deep in the pelvis. In addition, unroofing the hematoma loses all tamponade effect that the hematoma has provided. Venous injuries that have stopped bleeding may bleed again with real force once the pelvic fracture hematoma is entered.

Main hypogastric ligation typically is not selected as an operative procedure in most patients. While ligation may drop the perfusion pressure to the injured blood vessel, it may be insufficient to stop the bleeding, and, more importantly may negate the potential for the use of angiography, or the interventional radiologist may have to attempt access to the injured blood vessel through a ligated hypogastric artery.

Direct operative control may be indicated for selected patients; some authors suggest that patients with ongoing shock and stable pelvic fractures are more likely to be bleeding intraperitoneally and should undergo laparotomy; similar patients with unstable pelvic fractures are more likely to have a pelvic bleeding source, and therefore, should undergo angiography, and then laparotomy if necessary.31-33 Patients who present with hemorrhagic shock and a unilaterally absent femoral pulse generally have injury to the common iliac or external iliac artery. Prompt therapy obviously is necessary to salvage these patients; they are best served by direct operative control and bypass grafting of the injured blood vessel. These patients typically present with badly displaced posterior pelvic fractures and have essentially sustained a traumatic hemipelvectomy. The leg is attached only by skin and soft tissue.

Patients who present in refractory hemorrhagic shock from pelvic fracture bleeding sometimes may not survive until the angiography team can be mobilized; in selected centers, there may be a rule for direct operative control of this type of pelvic fracture bleeding in these patients.

Finally, bony fixation can stop bleeding. In patients with badly displaced SI joints, early percutaneous fixation is extremely attractive. The percutaneous nature of the procedure means that the pelvic hematoma is undisturbed. The SI joint is closed down and bony stability provided. While this action will not stop major arterial bleeding in most cases, it reduces the volume in the pelvis, provides definitive fixation, and allows for early mobility.

An Approach to Pelvic Fracture Bleeding. Several algorithms to treat pelvic fracture bleeding have been developed. A number of decision nodes exist; the first is to determine the hemodynamic stability of the patient. Hemodynamically unstable patients are managed in a very different manner than hemodynamically stable patients (See Figures 2 and 3.)

Complications of Pelvic Fractures

Thromboembolism is probably the most common complication following a pelvic fracture. The force needed to fracture a pelvis almost always disrupts some of the pelvic veins. The incidence of proximal deep vein thrombosis (DVT) with pelvic fractures has been reported to be 25-35%. The incidence of symptomatic pulmonary embolism is 2-10%.34 Certainly, every patient with a pelvic fracture should receive prophylaxis for DVT. Unfortunately, the potential hemorrhagic complications of pelvic fractures may make prophylaxis also somewhat dangerous. Recognizing a DVT on physical examination may be challenging on a patient with a pelvic fracture secondary to lower extremity swelling from fractures or fluid resuscitation. Duplex ultrasound examinations can be helpful in assessing for proximal venous thrombosis but almost never will be able to image the pelvic venous structures.

If possible, all patients should receive either unfractionated heparin or low molecular weight heparin and have sequential compression devices placed. If both therapies are not possible, at least one is better than no prophylaxis at all. Certainly, early fixation and aggressive mobilization are key to preventing DVT. Despite all efforts, however, these may not be possible.

Patients with significantly displaced pelvic fractures or those who have other concomitant critical illness injuries, should be evaluated for placement of a prophylactic inferior vena cava filter. While some may consider this procedure overly aggressive, prophylactic filter placement is relatively safe and should decrease the rate of pulmonary embolism.35,36 With the advent of retrievable filters, filters can be placed and then removed some weeks later when the risk of thromboembolic complications may be less significant.

The mortality for pelvic fractures is approximately 5-10%.2 In the past, this was due to hemorrhage, but it is no longer the case. Better organization of trauma systems and trauma centers has allowed for more expeditious management of pelvic fracture bleeding. While almost half of patients with pelvic fracture who die do so from hemorrhage, the hemorrhage may be from sources other than the pelvis. Other common sources of major morbidity involve traumatic brain injury, sepsis, and multiple organ failure.

Unfortunately, patients who survive may have significant ongoing morbidity. Pelvic fractures have significant associated pain, especially if fractures involve the sacrum or SI joints. Malunion or delayed union can cause leg length discrepancy or malrotation of the hemipelvis; both can alter gait mechanics.38 Other long-term complications involve sexual dysfunction and impotence. There is a surprising rate of genitourinary and lower gastrointestinal symptoms in patients with pelvic fractures, even in those patients who did not have an associated urologic or intestinal injury. Neurologic problems or impingement on visceral organs can occur secondary to the disturbed integrity of the pelvic ring.39,40 It is not clear whether treatment decisions affect long-term outcome. While some practitioners would argue that meticulous fracture fixation that restores the pelvic anatomy as close to normal as possible improves long-term outcome, the data are unconvincing. More work will need to be done to define long-term outcome and the role that therapy may have in it.

Penetrating Pelvic Injuries

Penetrating pelvic injury is treated largely the same as penetrating intra-abdominal injury. All structures in the pelvis are at risk from penetrating injury and must be evaluated. As with abdominal injury, any patient with transpelvic penetration and hypotension or peritonitis is best served by prompt laparotomy. In addition, patients with rectal bleeding can be explored for diagnosis, or they will require a colostomy. The abdomen can be explored first, followed by direct operative exploration of the pelvis. Injuries are identified and treated.

More controversial is the patient who presents hemodynamically stable following penetrating injury to the buttock or pelvis. Mandatory laparotomy in those patients will be negative approximately 95% of the time.41,42 Some authors advocate expectant observation in patients who are hemodynamically stable, and who do not have peritoneal signs, gross hematuria, or rectal bleeding.41,42 There are several approaches: The first involves serial physical examinations.43 A group at Los Angeles County Hospital has demonstrated clearly that careful physical examination during a 24-hour period will identify virtually all patients with significant injury. It is important to remember that this is a group of highly sophisticated clinicians who practice in a high volume trauma center, and the patients are managed on strict protocol. In doing so, missed injuries are identified early and treated before the patient suffers irreversible consequence.

The second option is to evaluate the patient with CT imaging. Historically, the triple contrast CT imaging was first described for the evaluation of patients with pelvic and retroperitoneal trajectories. In the original study, the abdomen was evaluated by DPL, and then the patient underwent CT imaging with oral, rectal, and intravenous contrast, which allowed the clinician to evaluate the patient for injuries that may not have been obvious on first presentation.

More recently, triple contrast CT imaging has been advanced as a way to image both the abdomen and retroperitoneum. Early results have been quite good. These include retroperitoneal colon injuries and injury to the ureter or bladder. CT imaging should identify trajectory adjacent to other important structures (e.g., vascular structures or the rectum), then, these can be investigated further with adjunctive studies such as proctoscopy and/or angiography.

Conclusion

The management of pelvic trauma can be challenging, but the same principles guiding all trauma care should be applied. Bleeding from blunt pelvic injury can be among the most difficult challenges facing any clinician caring for injury. It is important to keep institutional resources in mind and mobilize patients early to maximize outcome.

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