Pelvic rim or pelvic ring injuries without loss of pelvic stability (Fig. 17.2).

Type A fractures are stable fractures. Examples are avulsion fractures, iliac wing fractures, pubis or ischial rim fractures, as well as transverse sacral fractures below the sacroiliac joint.

Type B injuries are characterized by an anterior lesion of the pelvic girdle with partial disruption of the posterior ring segment (Fig. 17.3). In addition to instability of the anterior pelvic ring segment, the anterior ligamentous structures of the sacroiliac joint are damaged, mostly as a result of an anterior-posterior or a lateral energy impact. The posterior pelvic ring can be affected ipsilaterally, contralaterally, or bilaterally to the anterior lesion. External rotation injuries cause the so-called “open-book” mechanism, whereas internal rotation injuries are the result of a lateral compression with possible impression fracture of the ala of the sacrum or with partial rupture of the dorsal ligamentous structures of the sacroiliac joint.

The lateral compression can impact aslope, yielding a rotation of the affected hemipelvis in the vertical as well as in the sagittal pane. By disruption of additional ligamentous structures, this very unstable Type B injury is often difficult to differentiate from a type C injury. The one hemiplevis can be internally rotated like a handle of a bucket. Therefore, this injury type is termed by Pennal as a “bucket handle” injury.

The type C injuries are caused by translation or shearing movements of the involved hemipelvis resulting in a complete disruption of the anterior as well as the posterior pelvic ring segment (Fig. 17.4).

There exist different classifications for sacral fractures, which can appear with type A 3, type B, and type C fractures. For clinical daily practice, the classification according to Dennis (Fig. 17.5) has been proved.

This classification is based on three zones in relation to the sacral foramina. It is easy to remember and allows an estimation of the expected rate of neurological damage of the sacral neural plexus. Zone I is located laterally and zone III medially of the sacral foramina; zone II is bordered by the sacral foramina. Furthermore, longitudinal fractures, which can proceed from one of the above-called zones, are differentiated from transverse fractures.

Because of potentially extensive extravasation of blood volume and concomitant intraabdominal injuries, patients with pelvic fracture may face life-threatening injuries. In principle, the life-threatening situation (polytrauma, complex trauma, crush injury) must be distinguished from the hemodynamically stable situation in solitary pelvic ring injuries without danger to life. The diagnostic procedures as well as the emergency treatment must proceed according to a graduated scheme (ATLS® concept) in polytraumatized patients (Fig. 17.6).

The clinical history, which should essentially consider the injury mechanism, gives primary information for an injury of the pelvic girdle. Clinical examination starts with the inspection of all orifices and concomitant soft tissue injuries (wounds, hematomas, contusions, impalements).

Pelvic ring instability should be tested by gentle but firm compression and distractive movements of the iliac wings. The insertion of a urethral catheter is part of the primary diagnostic procedure. Urethral hemorrhage, scrotal hematoma, and difficult or impossible insertion of the urethral catheter must raise suspicion of a urogenital injury.

When the patient is alert, a precise neurological examination must be performed to exclude neurological damage; its frequency accounts for 11 % in complex trauma and 20–50 % in unstable fractures of the sacrum.

Basic diagnostic procedures include abdominal ultrasound and conventional pelvic X-rays. CT scan and angiography are considered extended diagnostic procedures.

In addition to appraisal of the stability of the pelvic girdle, differentiation between pelvic fractures without or with life-threatening bleeding is made during the initial treatment phase. In principle, two initial situations can be defined in accordance with the type (direct, indirect trauma, crush injury) and severity of energy impact: the life-threatening emergency situation in cases of complex trauma or crush injury with hemodynamic instability and the solitary osseous or ligamentous injury without hemodynamic effects.

Patients with pelvic ring injuries and life-threatening hemorrhages (hemoglobin < 8 mg/dl on arrival at the emergency room) should be managed according the “pelvic emergency algorithm” (Fig. 17.8). In cases of massive obvious hemorrhages following crush injuries or run-over, patients will be rushed to the operating room for emergency surgical procedures and, if necessary, emergency hemipelvectomy. In cases of life-threatening hemorrhages, where the source of bleeding is not obvious, it may be wise to initiate shock treatment and apply massive fluid challenge. When the patient is not responding to these procedures and is not in a hemodynamically stable condition within 10–15 min, self-tamponade of the bleeding into the retroperitoneal space cannot be assumed. These cases must be addressed by giving O negative packed red cells, and the pelvic girdle should be stabilized mechanically by external procedures to reduce the intrapelvic space. Bleeding caused by the cancellous bone and by the posterior sacral and anterior perivesical venous plexus will be compressed. The C-clamp (Fig. 17.15) is the appropriate external stabilizer for type C injuries. In cases of open-book injuries, the pelvic girdle can be closed using an anterior external fixator (Fig. 17.16).

In continuous hemodynamic instability passing the next 15–30 min, the patient should be transferred to the operating room to perform a packing tamponade. The incision is performed from the symphysis to the umbilicus. Extraperitoneal inspection of the pelvis follows. Massive hematoma is evacuated and the true pelvis is packed with tamponades at both sides of the bladder to the posterior presacral region. Packing is only helpful when counterpressure can be established after external stabilization of the pelvic ring. If necessary, the C-clamp should be adjusted. The anterior pelvic ring is stabilized by a single internal fixation (plate or tension band wiring). The definitive stabilization and reconstruction of the posterior pelvic ring may be performed secondarily if applicable during a second-look procedure of the pelvic package.

Using military anti-shock trousers (MAST) for external compression of the pelvic girdle does not avoid dissemination of the hematomas and, furthermore, may increase the danger of a severe compartmental syndrome. The MAST suit makes also the artificial ventilation and the clinical handling of the patient difficult. Therefore, this equipment has no relevance in this situation.