Special Feature

ED Management of the Unstable Patient with Pelvic Ring Trauma

By Michael A. Gibbs, MD, FACEP

P elvic ring fractures are the third most common cause of death from blunt trauma, behind head injury and aortic disruption. Despite advances in trauma care, the mortality associated with these injuries remains at least 10%. Because of the high risk of hemorrhage and associated injury, the ED management of pelvic trauma requires a sound understanding of the biomechanics of injury, clinical presentation, and essentials of early resuscitation. A reasoned diagnostic and therapeutic plan and the involvement of a multidisciplinary team are pivotal in the initial care of these complex injuries.

Table 1-Key Issues in the Evaluation of Pelvic Ring Trauma
- Is pelvic radiography indicated?
- Is the pelvic ring open?
- Is hemoperitoneum present?
- What are the essentials of early management?
- Where should the patient go from here?


The pelvic ring has impressive inherent strength and stability. Because major forces are required to disrupt this ring, fractures must always be considered a red flag for major multi-system trauma. This is not just another broken bone. The presence of a pelvic ring fracture may alter the sequence and/or technique of the initial diagnostic evaluation and will mandate that associated injuries be rapidly identified, prioritized, and managed either sequentially or in tandem. This article outlines an approach to the initial evaluation of the unstable patient with pelvic ring trauma, focusing on the key decision points shown in Table 1.

Question No. 1: Is Pelvic Radiography Indicated?

Detection of the injury is an obvious first step. Pelvic radiography should be routine in all severely injured, blunt trauma patients who are either hemodynamically unstable or obtunded, and in those with clinical evidence of pelvic injury (e.g., bruising, tenderness, instability).

Conversely, several studies suggest that pelvic radiography can be deferred safely in the stable, alert patient without these high-risk criteria.1-3 The anteroposterior (AP) radiograph will identify most pelvic fractures and in the majority of cases is sufficient to guide early management.3 This view should include the iliac crests, fifth lumbar vertebra, both hip joints, and the proximal portion of each femur. Examination of the anterior ring for pubic ramus fractures, symphysis disruption, or combined lesions should follow. Posterior pathology can present as iliac wing fractures, sacral fractures, or sacroiliac fracture/dislocations. While it is important to recognize that radiographs at right angles to each other (inlet and outlet views) provide a more accurate view of pelvic displacement than a single AP image, these should only be obtained if the patient has been stabilized. In the persistently hypotensive patient, do not delay or interrupt resuscitative efforts to obtain these additional views, especially when there is an indication for immediate laparotomy, pelvic angiography, or interfacility transport.

Question No. 2: Is the Pelvic Ring Open?

Injuries that open the pelvic ring, either in the lateral or vertical plane, increase pelvic volume, creating a potential space for ongoing hemorrhage. The classification system for pelvic ring fractures is based on the direction of the causative force vector and indirectly on whether the pelvic ring is open or closed.4 This schema describes three fracture types: lateral compression, AP compression, and vertical shear (see Figures 1-3). Lateral compression fractures are the most common injury type, accounting for roughly half of all cases. As the name suggests, the force is delivered to the pelvis from the side, as might occur in a "T-bone" motor vehicle collision (MVC) or when a pedestrian is struck from the side. The affected hemipelvis is crushed inward, the pelvic ring remains closed, and pelvic volume may actually decrease.

Lateral compression injuries typically are not associated with major bleeding. AP compression may occur following a head-on MVC or when a pedestrian is struck head-on by an oncoming vehicle. Anterior forces disrupt the ring at the symphysis or at vertically oriented pubic rami fractures. Posterior disruption follows at the sacroiliac joint or posterior bony pelvis. This causes the pelvis to open like a book, dramatically increasing pelvic volume and the risk of uncontrolled hemorrhage. Open-book pelvic fractures are major killers, and detection should trigger immediate vigorous resuscitation, pelvic stabilization, and rapid transfer to a trauma center.

Vertical shear injuries occur when the causative force vector is delivered to the pelvis from above or below. This usually is the result of a fall from a height or following a head-on motor vehicle crash in which the occupant has the leg fully extended. Alternatively, a downward force delivered to the pelvis via the spine, as may occur when a heavy object falls on the back or shoulders, may produce this injury pattern. One hemipelvis migrates vertically in relation to the other, causing complete ligamentous disruption and instability. As with AP compression fractures, the risk for hemorrhage is great, and the initial treatment paradigm should be the same.

Question No. 3: Is Hemoperitoneum Present?

During the resuscitation of the hemodynamically unstable patient with pelvic trauma, it is critical to rapidly identify the predominant site of hemorrhage.

Should pelvic bleeding pose the primary life-threat, angiography and skeletal stabilization is indicated. Conversely, if clinical instability is primarily the result of intra-abdominal hemorrhage, laparotomy should be performed first. (See algorithm in Figure 4.)

Taking a patient down the wrong branch of this algorithm can have devastating consequences: either uncontrolled pelvic hemorrhage in the operating room or intra-abdominal exsanguination in the angiography suite. By using diagnostic peritoneal lavage (DPL) or ultrasonography (US), the emergency physician can make the appropriate decision at the bedside.

The objective of DPL in this situation is to detect life-threatening abdominal hemorrhage and not just the presence of intraperitoneal blood. The DPL aspirate, not the cell count, should be used to guide decision making.5The aspiration of 5-10 cc of gross blood following the introduction of the catheter is considered "positive" and indicative of life-threatening abdominal hemorrhage. In the unstable patient, a positive peritoneal aspirate mandates immediate laparotomy, while a negative aspirate should be followed by pelvic angiography and vascular embolization. The open supraumbilical technique is preferred when performing the DPL in this setting.6 This avoids the risk of blindly entering an anterior abdominalwall hematoma dissecting cephalad from the pelvis and obtaining a false-positive aspirate. Bedside US also can be used to perform a rapid assessment for hemoperitoneum. An unequivocally positive US in the unstable patient with a pelvic fracture is an indication for immediate laparotomy.

Question No. 4: What are the Essentials of Early Management?

Anticipate and treat instability.

A common pitfall in the initial management of the patient with significant pelvic trauma is the failure to anticipate hypotension and initiate early, aggressiveresuscitation. In the setting of major blunt trauma, a pelvic fracture is an ominous finding and should immediately heighten the concern of the treating clinician. Adequate intravenous access with at least two large-bore intravenous catheters should be secured, and blood should be sent for type and cross-match. In the unstable patient, aggressive resuscitation with warmed crystalloid and early transfusion are essential. These patients have the potential to deteriorate rapidly. Monitor the patient carefully and pay close attention to the airway. This is especially important before long trips to the radiology suite and certainly before interfacility transport.

Stabilize the pelvis.

Injuries that increase pelvic volume (i.e., AP compression and vertical shear injuries) create a potential space for unabated hemorrhage. Rubash described a normal pelvic volume of 1.5 L. This increased to 3 L and 6 L with diastasis of the pubic symphysis of 3 cm and 6 cm, respectively.6 Pelvic stabilization provides benefit by reducing pelvic volume, stabilizing displaced fracture segments, and providing a tamponade effect on venous bleeding. This can be accomplished by several simple measures in the ED prior to the application of an external fixator or definitive operative repair. Internally rotating the lower extremities and wrapping a sheet tightly around the pelvis will close the pelvic ring to some degree. Application of MAST or a vacuum splint will help maintain reduction, limit pelvic motion, and tamponade venous bleeding. If the pelvic ring is open, this should be done before patient transfer.

Question No. 5: Where Should the Patient Go from Here?

The answer to this seemingly trivial question may be the difference between life and death for the patient. A few recommendations:

• Patients with significant pelvic ring trauma should be treated at a trauma center with a multidisciplinary team and immediate availability of an operating room and angiography suite. Transfer should be initiated with-out delay once the primary and secondary surveys have been completed, resuscitation has been initiated, and appropriate screening radiographs have been taken.

• Avoid the CT scanner trap. In the unstable patient, hemoperitoneum should be ruled out at the bedside, not in the radiology suite. Pelvic CT imaging is inappropriate in this setting, as it wastes valuable time.

• In the patient with a positive DPL aspirate or US, the next destination should be the OR. If these are negative, pelvic stabilization and angiography become the priority.

References

1. Koury HI, et al. Selective use of pelvic roentgenograms in blunt trauma patients. J Trauma 1993;34:236.

2. Yugueros P, et al. Unnecessary use of pelvic x-ray in blunt trauma. J Trauma 1995;39:722.

3. Salvino CK, et al. Routine pelvic x-ray in awake blunt trauma patients: A sensible policy? J Trauma 1992; 33:413.

4. Pennal GF, et al. Pelvic disruption: Assessment and classification. Clin Orthop 1980;151:12.

5. Moreno C, et al. Hemorrhage associated with major pelvic fractures: A multidisciplinary challenge. J Trauma 1986;26:987.

6. Cochran W, et al. Open versus closed diagnostic peritoneal lavage: A multiphasic prospective randomized comparison. Ann Surg 1984;200:24.

7. Rubash HE, Mears DC. External and Internal Fixation of the Pelvis. In: AAOS Instructional Course Lecture. St. Louis: CV Mosby; 1983, p. 329.