Pelvic Trauma

Etiology

The pelvic ring is a very solid structure, requiring a great force to disrupt the complex. Therefore pelvic fractures are relatively uncommon. The majority of pelvic fractures result from motor vehicle collisions (MVCs), falls from height, or a pedestrian or cyclist struck by a vehicle.[4][5] There is, however, a high rate of associated injuries, occurring in 12% to 62% of patients with pelvic fractures.

Epidemiology

Pelvic fractures make up about 10% of fractures in blunt trauma patients. Over 16% of patients with pelvic fractures have at least one associated injury.[6] The most commonly injured structures are intraabdominal, with the liver, spleen, and kidneys occurring most often. Urogenital lesions account for over 40% of associated injuries. It is estimated that up to 24% of pelvic trauma patients have a urethral injury, and 20% have an associated bladder laceration. Most urethral injuries in males are located at the bulbomembranous junction.[7] One to two percent of traumatic rectal injuries are due to pelvic fractures.[8] Vaginal lacerations are reported in 2% to 4% of pelvic fractures. The American Association for the Surgery of Trauma (AAST) divides vaginal injuries into three degrees: I-III. First-degree includes contusion, hematoma, and superficial laceration involving only the mucosa. A second-degree laceration involves deep fat or muscle. Third-degree lacerations involve the cervix or peritoneum or injury into adjacent organs.[9]

Pelvic nerves and vascular lesions are also relatively common.[10] The most commonly injured arteries are anterior branches of the internal iliac artery: superior gluteal artery, lateral sacral artery, and the pedestal and obturator arteries. The most common veins injured are the presacral plexus and the prevesical veins.[11] Blood loss can also come from the fractured bones.[12]

Pathophysiology

Disruption of the pelvic ring causes an increase in the internal volume of the pelvis. The increased volume will decrease the tamponade effect of the retroperitoneal space, allowing increased blood loss.[4][13]

There are two main classification systems of pelvic fractures: the Tile and the Young-Burgess classification systems. Tile et al. described three types of underlying mechanisms for pelvic fractures. Type A is a rotationally and vertically stable fracture. Type B is rotationally unstable but vertically stable. Finally, type C is both rotationally and vertically unstable.[4] The Young-Burgess classification consists of anteroposterior compression (APC), lateral compression (LC), vertical shear (VS), or a combined mechanism (CM). Anteroposterior compression fractures are often unstable; these are the “open book” pelvic fractures. They are associated with pelvic and retroperitoneal hemorrhage. They typically occur from a head-on MVC. Lateral compression is the most common. These fractures are often stable but can be associated with a bladder rupture. These commonly result from a T-bone MVC or a pedestrian hit from the side. A vertical shear injury is usually unstable. They require a substantial force on one or both hemipelves, such as a jump from a tall height or being hit by a falling tree. They cause complete ligamentous injury.[14][15]

The Young-Burgess and Tile classification both classify pelvic fractures on the anatomic classification of injuries but fail to consider hemodynamic stability. The World Society of Emergency Surgery (WSES) created a classification that is based on anatomic classification as well as the hemodynamic stability of the patient; this helps with consideration of a treatment algorithm. The WSES classification divides pelvic injuries into three categories: mild, moderate, and severe. 

• Minor: WSES grade I; the fracture is stable, and the patient is hemodynamically stable
• Grade I: APC I and LC I fractures
• Moderate: WSES grade II and grade III; the fracture is unstable, but the patient is hemodynamically stable
• Grade II: APC II, APC III, and LC II, LC III fractures 
• Grade III: VS and CM fractures
• Severe: WSES grade IV: the fracture is either stable or unstable, but the patient is hemodynamically unstable.
• Grade IV: any fracture pattern in a hemodynamically unstable patient

Minor injuries are typically treated with nonoperative management. Moderate injuries are given a pelvic binder in the field, and then should be considered for angioembolization if a blush is seen on CT scan. Severe injuries require more intense intervention. A pelvic binder should be placed in the field. Upon arrival, the patient should be treated with preperitoneal packing, resuscitative endovascular balloon occlusion of the aorta (REBOA), or angioembolization.[4] These treatment options will be discussed in more detail below.

History and Physical

The initial approach to any trauma patient is described in the Advanced Trauma Life Support (ATLS) course; it is a structured and standardized approach. The approach is meant to recognize and stabilize life-threatening injuries first. It is important to note an initial detailed history is not essential to begin evaluating a patient with acute injuries. The emergency medical system (EMS) personnel bringing the patient to the trauma/resuscitation area of the emergency department (ED) will provide a brief history of present illness. After the initial evaluation and stabilization of the patient, a detailed history can be obtained. A few useful facts include the mechanism of injury, whether the patient was ambulatory at the scene, bowel or bladder incontinence, and any numbness or weakness. In an awake trauma patient, the history and physical exam are highly sensitive for pelvic trauma.[16]

Evaluation

The initial evaluation of the trauma patient is the primary survey. The mnemonic ABCDE is a helpful way to remember the order of the evaluation.

• A: Airway and cervical spine protection. An easy way to assess the airway is to have the patient speak. Ask them their name.
• B: Breathing. Listen for bilateral breath sounds and look at the chest wall motion during the respiratory cycle
• C: Circulation. This helps determine whether the patient is in shock.
• D: Disability. This is the Glasgow coma scale (GCS)
• E: Exposure and environmental control. Here the examiner undresses the patient the provide head-to-toe evaluation for injury.

The secondary survey follows the primary survey.[17] This is a head-to-toe complete exam. A digital rectal exam should also be performed during the secondary survey. Gross blood indicates a gastrointestinal injury. A high riding prostate, blood at the urethral meatus, an inability to void, or gross hematuria could be another indication of a urethral injury.[4][18] The pelvis is assessed with anteroposterior compression. Perineal hematoma and edema should also raise suspicion for pelvic content injuries. Any instability indicates a pelvic fracture. Any compressive force causing movement of the pelvis can disrupt any hemostasis that has occurred, so this force is generally limited to a single attempt.[17][19]

Laboratory markers are often useful in traumatic settings. Sensitive markers for hemorrhage include serum lactate level and a base deficit, which can both be obtained from an arterial blood gas. Serum lactate and base deficit can also be used to monitor resuscitation. It is important to remember hemoglobin or hematocrit levels are not sensitive for identifying acute traumatic hemorrhage.[4][5] Other useful laboratory markers are coagulation panels, such as PTT, PT/INR, and fibrinogen levels. Patients that have undergone a traumatic injury are susceptible to coagulopathy, increasing their mortality risk.[4] Thromboelastography (TEG) or rotational thromboelastometry (ROTEM) are useful tools to allow targeted resuscitation with blood products.[20]

Multiple imaging modalities can be useful in evaluating pelvic trauma. An ultrasound can be used to perform a Focused Assessment with Sonography in Trauma (FAST) exam while in the trauma/resuscitation area. A FAST exam is used to identify free fluid. It cannot differentiate bowel contents from blood.[21] Pelvic x-rays in a hemodynamically unstable patient may help identify potentially life-threatening causes of injury. If the patient is unstable, a quick x-ray can direct care. It is still important to remember there are likely additional injuries, so a pelvic fracture may not be the sole cause of instability. A pelvic x-ray is also useful to evaluate for hip pathology, such as a fracture or dislocation that needs quick reduction.[22]

X-ray, while useful for quick evaluation in an unstable patient, is still inferior to computed tomography (CT) for the evaluation of fractures.[22] CT scanning remains the gold standard. A CT scan not only identifies fractures but has the ability for three-dimensional bone reconstruction. 3-D reconstruction allows better operative planning for patients.[4] The ability to add contrast increases the ability to find injuries. A triple-phase contrast-enhanced CT consists of an arterial phase, a portal phase, and a delayed phase.[4][23] A blush on the arterial phase indicates active arterial bleedings; it can be seen as a hyperdensity within a hematoma. A delayed phase will show injuries to urologic structures. CT scan also has the benefit of adding rectal contrast in cases where a rectal injury is suspected.

A urethrogram can help diagnose a urethral injury. As urethral injuries alone are not life-threatening, any vascular or visceral injury should be managed prior to undergoing urethrogram. In the trauma setting, a urethrogram should be performed in a fluoroscopic suite by a trained radiologist. In an ascending study, a 6-8 French Foley catheter is inserted into the fossa navicularis, which is just beyond the meatus. The foley balloon is filled with 2 to 3 mL of water. A C-arm is brought over the bed and is rotated to either the left or right 30 degrees to an anterior oblique position. The patient then elevates his left side to the same degree. 30 mL of iodinated contrast is slowly injected into the foley catheter until the contrast is visualized within the bladder. A descending study fills the bladder with 400 mL of contrast. The patient is then asked to micturate into a bottle in a standing oblique position. An injury is visualized as contrast extravasation. A complete urethral transection typically requires both an ascending and descending urethrogram to estimate the length of transection.[18][24][25]

Treatment / Management

Pelvic fractures, no matter the grade, have the potential to become life-threatening. Treatment for pelvic fractures starts with the ABCs (airway, breathing, and circulation) during the primary survey. Adequate resuscitation is crucial in any trauma patient. Two large-bore IVs should be placed in all patients arriving at the trauma bay. Hypotension should be addressed with aggressive fluid resuscitation, followed by blood products if the patient remains hypotensive.

Pelvic binders should be placed when there are signs of pelvic ring disruption in either stable or unstable patients. The binder acts in two ways to decrease bleeding. It compresses the bleeding from the bones, but they also decrease the volume within the pelvis. By decreasing the volume, it promotes a tamponade effect. Pelvic binders are a temporary measure until a more definitive repair can occur. The pelvic binder is only useful if it is applied correctly; The binder must be placed around the greater trochanter and pubic symphysis to adduct the legs and decrease pelvic volume correctly.[4][26] A pelvic binder should not be placed in a lateral fracture, as this can increase bleeding.[27](B2)

Hemodynamically Stable Pelvic Fractures

Evidence of arterial bleed on CT should go directly for angioembolization. Pelvic angiography is usually performed by interventional radiology (IR). Angioembolization is successful in 85% to 100% of cases.[28] Angioembolization is usually performed via a femoral artery approach. If the femoral is unavailable, the left brachial or axillary artery may be used. In the best circumstances, a single bleeding vessel is visualized and embolized. In some circumstances, there are multiple bleeding vessels, or the single bleeding vessel cannot be accessed. In this situation, a nonselective, or “shotgun” approach can be performed. This is possible due to the vast collateral network within the pelvis. The most common vessels for embolization are the internal iliac artery and its branches: the superior gluteal artery, the obturator artery, and the internal pudendal artery. Absorbable gelatin compressed sponge and coils are typically used for embolization. Absorbable gelatin compressed sponge is a temporary agent that is inexpensive and readily available. Coils are permanent. Coils only work if the coagulation pathway is intact, as they induce a thrombotic effect leading to clot formation and occlusion.[29] After embolization, a completion angiogram is used to confirm the bleeding has stopped.[30][27] Studies have shown angioembolization within 90 minutes of arrival to the hospital had improved survival rates.[31] Angioembolization can be repeated in patients with continued hemorrhage and hemodynamic instability after first embolization. (A1)

Patients with hemodynamic stable pelvic fractures should be admitted to the hospital for observation.

Hemodynamically Unstable Pelvic Fractures

Generally, patients will go for immediate laparotomy if they remain unstable with concern for injury. However, many authors argue angioembolization should be done prior to going to the operating room (OR). The basis of the argument is there is a high likelihood of finding an arterial bleeding source, and because there is a strong correlation between time to embolization and survival as stated above. 

Preperitoneal packing (PPP) involves putting packing up against the peritoneum to create a tamponade effect. It is less time consuming than angioembolization. Preperitoneal packing is useful for hemodynamically unstable patients at centers without IR. It can also be used as a bridge to more time-consuming procedures, such as angioembolization, at level 1 trauma centers. Another important use is in patients that are hemodynamically unstable and require other life-saving surgical intervention. Packing is performed through a vertical midline incision of 6 to 8 cm or Pfannenstiel incision. Dissection continues down to fascia; fascia is then incised in the midline to access the preperitoneal space. Ringed forceps are then used to put three surgical pads into the space, with the first being pushed all the way to the sacrum. The same is performed on the contralateral side. Six surgical pads are typically enough to complete the packing. The fascia is then quickly closed over the surgical pads, and the skin is closed in a running fashion.[32]

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an alternative to cross-clamping the aorta. REBOA has emerged in recent years at trauma centers around the world. It uses a balloon catheter to occlude the aorta in an attempt to minimize life-threatening hemorrhage. It has been speculated that REBOA can be useful in pelvic trauma. Literature has shown zone III (infra-renal) occlusion is useful in pelvic trauma as it has little visceral organ insult.[4][33] The common femoral artery is typically used for access. If there is a suspected femoral or iliac injury, one side of the contralateral side should be accessed. An 18G needle is used to access the artery. A guidewire is introduced into the needle and advanced into the vascular system. The needle is removed, and the tract is dilated until a 7 Fr sheath can be inserted into the vessel. The catheter position is measured by measuring the distance from the umbilicus to the femoral catheter insertion site and is then inflated until moderate resistance is felt or there is a loss in the contralateral pulse, typically 15 to 20 mL in the balloon for zone III deployments. The patient should then be expedited to either IR or the OR for definitive treatment. REBOA inflation time is ideally less than 30 minutes but can be used for up to 60 minutes. Upon deflating REBOA, hemodynamic changes can be noted. The balloon can be intermittently reinflated to allow resuscitation and reduce reperfusion injury. The femoral artery access site may require surgical repair.[34] If a common femoral access site is not available, then the left brachial or left common carotid artery may be used.[35][36][37](A1)

Unstable pelvic fractures require surgical fixation. Early fixation has been shown to improve pain, improved fracture reduction, earlier mobilization, and control of bleeding from fractured bones.[4][38] There are a few surgical options available. External fixation allows initial stabilization in hemodynamically unstable patients and those with pelvic contamination. It is generally placed within the operating room. The common pin locations are the iliac wings and the anterior inferior iliac spine. The iliac wing is accessed by making an incision about 2 cm posterior to the anterior superior iliac spine down to the bone. The gluteal ridge is the target insertion spot due to its strength. The pin is inserted manually.[39] Anterior inferior iliac spine pins have greater pullout strength and provide better access for reduction. These two options only provide anterior pelvis fixation. For VS injuries, posterior stabilization is required with skeletal traction.[40][41] Generally, iliac wing fracture or acetabular fracture are contraindications to external fixation. 

Definitive repair, if needed, is undertaken once the patient has been adequately resuscitated and stabilized. Patients that are hemodynamically stable or “borderline” can be safely taken for definitive repair within 24 hours of injury. Physiologically deranged polytrauma patients should not be taken for definitive repair until they are stable. Studies show post-injury complication rates are increased if definitive repair is completed within four days of injury in polytrauma patients. Complications decreased when surgery was delayed until six to eight days post-injury. [42] Therefore, it is recommended to wait at least four days to proceed with any definitive treatment of pelvic fractures. Posterior ring injury reconstructions are most important for functional outcomes. APC I and LC I are managed nonoperatively. APC II is typically managed with anterior symphyseal plating. APC III is treated with either anterior symphyseal multihole plating or external fixation with posterior stabilization with sacroiliac screws. LC II is treated with ORIF of the ilium. LC III and VS require posterior stabilization with sacroiliac screws. It can be done open or percutaneous based.[43][44][45] Open reduction and internal fixation provides a better repair and allows earlier mobilization. Percutaneous fixation of the posterior ring can be useful in patients with traumatic posterior skin injuries.[38](B2)

Associated bladder injuries may require repair. The location of the injury dictates the management. Generally, extraperitoneal bladder injuries are treated nonoperatively; intraperitoneal bladder injuries require surgical repair. A foley catheter remains in place for about 14 days. A repeat cystogram should be performed prior to catheter removal.[46] Urethral injuries are possible with pelvic fractures. Complete transection of the urethra should be treated with a suprapubic catheter and delayed repair; partial transection is manageable with a foley catheter. [25] Any associated perineal injury should be closely monitored for vesicocutaneous or urethrocutaneous fistula formation.[47](B2)

Sigmoid and intraperitoneal rectal injuries should be debrided and primarily repaired when able. An injury comprising less than 50% circumference is eligible for primary repair. This has been shown to reduce complications. For injuries that cannot be primarily repaired, resection with primary anastomosis is usually performed with or without fecal diversion.[48] For injuries that are greater than 50%, the colon or rectum should be debrided to healthy tissue. Then a primary anastomosis or diversion can be performed. Extraperitoneal rectal injuries are treated with primary repair with a diverting colostomy.[49] Recent studies have shown no use for presacral drainage or distal washout for extraperitoneal rectal injuries.[50](B2)

Vaginal laceration treatment is dependent on the degree. First-degree injuries generally only require gauze packing. Second and third-degree injuries require surgical repair, typically by a gynecologist.[9](B2)

Differential Diagnosis

• Acetabular pelvic fracture
• Bladder injury
• Hip fracture
• Hip dislocation
• Urethral transection
• Open book pelvic fracture
• Rectal injury
• Sigmoid injury
• Urethral transection
• Vertical shear pelvic fracture

Prognosis

Unstable pelvic fractures have a mortality of about 8%. Patients that are in hemorrhagic shock at presentation have increased mortality. Patients that present with an open pelvic fracture have a mortality risk of up to 45%. As noted earlier, the seriousness of pelvic fractures stems from the associated injuries; the risk of death from isolated pelvic fracture ranges from 0.4% to 0.8%.[12][51][52]

Complications

The associated injuries with pelvic fractures make prognostic measurements difficult. One study showed that over 60% of patients with traumatic pelvic fractures experience chronic pelvic pain. Chronic pain is associated with depression and anxiety. External fixation is associated with pin site infections that can be treated with PO or IV antibiotics +/- debridement of site. Lateral femoral cutaneous nerve injury can also occur from external fixation.[53]

Urogenital injuries can be associated with sexual dysfunction, such as dyspareunia, erectile dysfunction, and restricted motion. Urinary and fecal incontinence are also possible. Urethral strictures have been reported in 31% to 69% of complete urethral transections.[18] Urethral strictures can be treated conservatively with dilation. However, if dilation fails repair with posterior urethroplasty, also called bulbomembranous anastomosis (BMA), may be required. BMA success rates are over 90%.[25]

Urinary incontinence is initially treated conservatively. Pelvic floor strengthening and biofeedback are used initially. Duloxetine, a selective serotonin/norepinephrine reuptake inhibitor is used in combination with physiotherapy successfully in many patients.[54] A sacral nerve stimulator can be implanted within the upper buttock and has been used to treat incontinence successfully.[55] Urinary incontinence can be treated with artificial urinary sphincter implantation when other methods fail.[7]

Similarly, fecal incontinence starts with nonoperative management. Dietary changes and fiber supplements can optimize stool consistency and limit urgency. Medications can be used to slow the bowels. Examples include the antidiarrheals Imodium and Lomotil, the bile acid binder cholestyramine, and medications the reduce the reflexive relaxation of the sphincter, such as amitriptyline. Physical therapy and biofeedback have been used successfully to strengthen the pelvic floor. If conservative treatments fail, a sphincteroplasty can be performed. Other options include implanting artificial anal sphincters or magnetic anal sphincters. Sacral nerve stimulators can also be successful.[56]

It is important to note a pelvic binder itself can cause complications. A pelvic binder should not be placed for more than 24 hours. The binder can cause skin necrosis and pressure ulcers as soon as 2 to 3 hours after placement.[4] There is a high risk of deep venous thrombosis with all trauma patients; this risk is compounded by decreased mobility and bone fractures. Patients should be treated with mechanical serial compression devices and chemoprophylaxis until they are ambulatory.

Complications from angioembolization occur in up to 5% of cases. Complications can occur at the access site and include hematoma, pseudoaneurysm, dissection, or thrombus. Pelvic tissue necrosis can be a life-threatening complication and requires exploration and repair. Patients can have a reaction to the contrast itself or develop contrast nephropathy and an acute kidney injury. 

Potential REBOA complications are numerous and mainly involve vessel injuries. The balloon can cause an arterial rupture, perforation, or dissection. The catheter itself can create lower extremity ischemia and subsequent reperfusion injury and compartment syndrome. Balloon occlusion also leads to distal ischemia. Prolonged occlusion leads to organ ischemia, which can be irreversible. Organ reperfusion can lead to multiorgan dysfunction or failure, including acute kidney injury, liver failure, intestinal ischemia, spinal cord infarction, and death. Access site complications can be treated with patch repairs, arterial reconstructions with native or artificial tissue, or bypasses. If these measures fail, then the limb would require amputation. Aortic injuries from REBOA are generally life or limb-threatening. Multiorgan dysfunction is generally treated medically.[35][36]