Multidisciplinary management of pelvic fractures: Operative and nonoperative management

Incidence

Pelvic fractures following blunt trauma are reported to represent approximately 3% of all bony injuries, and the incidence of pelvic fractures has been variably reported to be between 2 and 37 per 100,000 person-years. Notably, there is a bimodal age peak in the incidence of pelvic fractures, with high-energy unstable fractures occurring in teens and young adults and low-energy fractures occurring most commonly in elderly patient populations. The incidence significantly increases with age.

Anatomic considerations

The bony pelvis is composed of the strongest ligaments in the body; thus, the force required to both fracture the pelvis and produce pelvic ligamentous instability is significant. Although the bony pelvic ring consists of the two paired innominate bones—sacrum and coccyx—there is no inherent stability to the bony pelvic girdle. Anteriorly, the innominate bones join each other at the pubic symphysis and both join the sacrum at the sacroiliac (SI) joint. The innominate bones and sacrum are held in a structural unit primarily by the ligaments of the pelvis, which comprise the vertical stability across the SI joints and the pelvic floor. These ligamentous complexes, especially the posterior elements, provide stability for articulations of the pelvis. Pelvic fractures can injure not only the bony pelvis and its ligamentous complexes, but also the hypogastric arteries, the pelvic venous plexus, the sciatic nerve, and pelvic organs including bladder, urethra, and rectum, all of which lie within the bony pelvis.

Mechanism of injury

Some mechanisms of injury are more likely to result in pelvic fractures because of pelvic anatomy. Vehicular crashes are the most common cause of pelvic injury in most environments, followed in order of frequency by automobile-pedestrian collisions, falls from a height, motorcycle crashes, and crush injuries. Owing to a variety of age-related changes in the pelvis, lower-energy mechanisms such as minor motor vehicle crashes and mechanical falls are frequently the source of pelvic fractures in geriatric patients. Although typically not associated with the degree of bony instability seen with high-energy fracture patterns, these fractures may be associated with significant hemorrhage and hemodynamic instability.

Diagnosis

In classic surgical teaching, there are five areas into which a patient can exsanguinate: the thorax, abdomen, retroperitoneum, muscle compartments (especially thigh), and externally. In the patient presenting with polytrauma, prompt and accurate identification of the source of bleeding is of the greatest importance. Up to 20% of patients with pelvic fractures will have concomitant thoracic injuries, and intrathoracic bleeding can be identified via physical examination, chest radiographs, or ultrasound examination, with tension pneumothorax and massive hemothorax able to be rapidly treated with tube thoracostomy. Muscle compartment bleeding should be readily identifiable on physical examination, and external blood loss can generally be diagnosed by history from prehospital providers and physical examination, although it is important to recall that external blood loss may become evident only after a hypotensive patient is appropriately resuscitated and blood pressure increases. It is critical to resuscitate hemodynamically unstable patients with using balanced blood transfusion rather than crystalloid fluids in concert with rapidly diagnosing the source of hemorrhage as excessive use of crystalloids is associated with the development of traumatic coagulopathy.

Making the distinction between intra-abdominal and retroperitoneal bleeding can be challenging, as combined abdominal and pelvic injuries are extremely common. Physical examination findings such as abdominal pain, distention, or tenderness do not differentiate between intra-abdominal and retroperitoneal bleeding, and these findings can be quite nonspecific. Moreover, patients can have minimal physical examination findings in the setting of significant abdominal and retroperitoneal hemorrhage. Historically, the diagnosis of intra-abdominal injury in hemodynamically labile patients was made by diagnostic peritoneal lavage; however, the advent of the focused ultrasound examination revolutionized the early diagnosis of intra-abdominal injury in unstable patients. The focused assessment with sonography in trauma (FAST) examination is a rapid bedside ultrasound technique that can identify intra-abdominal injury within several minutes. It is portable and repeated easily in the setting of equivocal results or with any change in hemodynamic status and has been shown to reliably identify clinically important intra-abdominal bleeding in the setting of severe pelvic hemorrhage. Limitations to FAST include that it is user-dependent and nonspecific—it is able to quickly identify the presence of intra-abdominal fluid but does not localize the source of bleeding. Cross-sectional imaging such as computed tomography (CT) scanning allows for detailed, rapid imaging of both intra-abdominal as well as retroperitoneal structures and can readily identify sources of blood loss into both compartments. CT scanning is more sensitive and specific than the FAST in identifying intra-abdominal injuries, as approximately 25% of patients with pelvic fractures will have intra-abdominal injuries despite a true negative FAST. Thus, CT scanning should be performed in all patients with pelvic fractures to fully evaluate abdominal and retroperitoneal injuries at some point during the evaluation process. However, performing a CT scan is relatively time-consuming and may require transport away from the resuscitation unit—so there is limited utility and significant danger in obtaining a CT scan early in the workup of a hemodynamically unstable patient.

Retroperitoneal hemorrhage should be suspected in any patient with a pelvic fracture. Upon presentation, patients can be rapidly evaluated for pelvic fracture via physical examination and screening pelvic radiography. Initial physical examination of the pelvis can be helpful in determining skeletal stability even before a radiograph is taken. Although some advocate rocking the pelvis, we consider this to be a potentially dangerous maneuver, as in patients with skeletally unstable pelvic fractures, this produces pain and may displace the fracture fragments, exacerbating bleeding that had previously stopped. Instead, we encourage clinicians on initial assessment to gently compress the pelvis inward at the level of the iliac crest. This maneuver is specific, but not very sensitive. If there is “give” in the pelvis with compression, the patient almost certainly has a skeletally unstable pelvic fracture. Absence of movement does not exclude the diagnosis of a pelvic fractures. During initial patient assessment, a pelvic radiograph should also be performed as a rapid screening test that should alert the clinician to the possibility of pelvic fracture and hemorrhage. Although a good screening test, pelvic radiograph is limited to describing pelvic bony anatomy in only two dimensions and can vastly underestimate the degree of a pelvic bony injury posteriorly, especially compared with a CT scan. However, radiographic injury patterns identified in the screening pelvic radiograph such as widened symphysis pubis diastasis, SI joint widening, or “butterfly fracture” in which all four pubic rami are fractured indicate a severe injury pattern that often will require pelvic angiography, as these fractures are traditionally associated with severe pelvic bleeding.

When caring for patients with pelvic fractures, it is important to distinguish between patients with skeletally unstable pelvic fractures and patients who are hemodynamically unstable. Skeletal stability describes the bony architecture of the pelvic fracture whereas hemodynamic stability describes the patient’s physiologic response. Not all patients with skeletally unstable pelvic fractures are hemodynamically unstable, and more importantly, patients who have skeletally stable fractures can have significant retroperitoneal hemorrhage and be hemodynamically unstable.

Any patient with a suspected or confirmed pelvic fracture that has a positive FAST and hemodynamic instability is almost certainly best served by an immediate laparotomy. In many patients, the hemoperitoneum can be detected on FAST with as little 200 mL of fluid in the abdomen ( Fig. 1 ). Although intra-abdominal free fluid can result from a nonhemorrhagic source, such as a ruptured hollow viscus, proceeding to an emergent laparotomy is often the most rapid and definitive test in patients who are hemodynamically unstable to diagnose and control severe hemorrhage. If minor intra-abdominal injury is identified on exploration, and pelvic bleeding is thought to be ongoing, abbreviated laparotomy can be performed and pelvic hemorrhage managed through other methodology such as angiography or packing.

Anatomic location of injury and injury grading

There are several available classification schemes to describe the bony architecture of pelvic fractures including the Tile and Young-Burgess classification systems. The most commonly used scheme was described by Young et al in 1986 and Burgess et al in 1990 and classifies three major types pelvic fractures by their vector of force ( Table 1 ): anteroposterior compression fracture, lateral compression (LC) fractures, and vertical shear (VS) injuries. Each classification is subdivided to describe the degree of skeletal displacement, which is useful in describing both fracture anatomy and guiding initial attempts at hemostasis. The notion that fracture anatomy could predict bleeding has been long debated—for instance, one study reported on the use of angiography and embolization for pelvic hemostasis and demonstrated that low-grade anteroposterior (AP) compression fractures required angiography most often; however, in another study, the Young-Burgess classification was found to predict transfusion requirements. A more recent multicenter study demonstrated that hemodynamically unstable blunt trauma patients with anterior-posterior compression III fracture patterns or patients with open pelvic fracture are at greatest risk of bleeding requiring a pelvic hemorrhage control intervention, reinforcing the importance of pelvic fracture pattern in predicting the need for intervention.

LC pelvic fractures caused by side impact generally occur after broadside (T-bone) vehicular crashes or car-pedestrian collisions ( Fig. 2 ) and cause an acute shortening of the pelvic diameter, where the pelvic ring does not open but rather “closes down.” With LC fractures, the pelvic ligaments generally stay intact and these fractures classically do not bleed. Therefore, hemodynamic instability after an LC fracture is more likely a result of associated torso injuries leading to intra-abdominal or intrathoracic bleeding. However, geriatric patients are the exception and can have a substantial risk of hemorrhage despite a relatively benign-appearing fracture pattern. In fact, one study demonstrated that LC fractures were more common in patients over the age of 55 years, and these patients were two times more likely to require transfusion compared with younger patients and required more overall blood transfusions (7.5 vs. 5 units). Although these LC fractures were minor, the patients had substantial bleeding and, not surprisingly, the overall mortality rate was also higher in older patients.

AP compression fractures generally occur after frontal vehicular crashes or pelvic crush injuries with the force following in the anteroposterior direction ( Fig. 3 ). After injury, the pelvic diameter widens and the pelvis opens. This injury may be purely ligamentous if the SI joints rupture, even in the absence of significant bony injury, and is commonly associated with pelvic vascular injuries. As such, AP compression fractures have the highest associated rate of hemorrhage, and transfusion requirements are the highest in patients with these fractures.

VS injuries occur when patients land on an outstretched foot, which generally occurs after falling from a height or in motorcycle crashes, particularly if patients are riding with their legs outstretched ( Fig. 4 ). In VS fractures, the force is transmitted up the axial skeleton through the posterior pelvis and posterior fractures and ligamentous ruptures are common. With VS fractures, if there is a complete disruption of both the anterior and posterior elements (Malgaigne fracture), then the psoas muscle pulls the ipsilateral hemipelvis cephalad without opposition, which may be visualized on a pelvic radiograph. VS injuries have an intermediate risk of bleeding in the Young and Burgess classification of pelvic fractures and are considered unstable.

Pelvic fractures do not always occur in pure form as described by the classification system, such as when a pedestrian is struck obliquely, and a clear classification may not be obvious based on the pattern of injury. However, the site of bleeding often correlates with pelvic fracture anatomy: AP compression fractures generally bleed from either the pudendal or obturator artery, VS fractures most often bleed from the superior gluteal artery, and, if LC fractures bleed, it can be from virtually any vascular structure. Although fracture anatomy and available classification systems may be able to predict both the likelihood and location of bleeding, they are far from perfect and the astute clinician will recognize that any patient with a pelvic fracture can bleed regardless of fracture pattern. In clinical practice, injured patients with pelvic fracture and evidence of ongoing blood loss should undergo investigation for blood loss in other cavities, and if none are found, it should be assumed that the patient is probably bleeding from the pelvis and retroperitoneum. Importantly, regardless of the pelvic fracture anatomy, in a hemorrhaging patient, prompt action should be taken to rapidly obtain hemostasis.

Management

Pelvic hemorrhage can stem from several sources, and there are a number of techniques available to stop bleeding from the bony pelvis. The vast majority of bleeding related to pelvic fractures is venous in origin and—although often of significant volume—tends to be relatively self-limited as the pelvic hematoma itself tamponades most low-pressure vascular injuries. Hemorrhaging pelvic fracture patients can bleed from both fracture fragments themselves as well as smaller pelvic arterial injuries, and large-volume pelvic hemorrhage can result from larger arteries such as major branches of the hypogastric distribution (pudendal, obturator, or superior gluteal artery). Major vascular structures, such as the proximal hypogastric, external, or common iliac artery, are rarely the source of major hemorrhage in typical pelvic fractures; however, when these vessels are injured, bleeding is typically massive and the patients are almost uniformly hemodynamically unstable. Hemostatic techniques for pelvic fracture bleeding include external compressive devices, temporizing techniques such as resuscitative endovascular balloon occlusion of the aorta (REBOA) and pelvic packing, angiographic embolization, and open vascular control. Bony stabilization is also helpful in establishing hemostasis.