Abstract
- Severe bleeding in complex pelvic fractures usually originates from branches of the internal iliac artery, presacral venous plexus, fractured bones, and soft tissues. Major iliac vascular injuries are encountered in about 10% of patients with severe pelvic fracture.
- The abdominal aorta bifurcates into the two common iliac arteries at the L4-L5 level. The iliac veins are located posterior and to the right of the common iliac arteries. The ureter crosses over the bifurcation of the common iliac artery as it branches into the external and internal iliac arteries.
- The internal iliac artery is about 4 cm long. At the level of the greater sciatic foramen, it divides into the anterior and posterior trunks. It supplies numerous splanchnic and muscular branches and terminates as the internal pudendal artery, which is a potential source of hemorrhage in anterior ring disruptions. Hemorrhage following pelvic fracture can occur from any branch.
- The most commonly injured internal iliac artery branches (in decreasing order of frequency) are the superior gluteal, internal pudendal, and obturator arteries.
- The superior gluteal artery is the largest branch of the internal iliac artery. It exits the pelvis through the greater sciatic foramen above the piriformis muscle. It provides blood supply to gluteus medius and minimus muscles.
- The internal pudendal artery passes through the greater sciatic foramen, courses around the sciatic spine, and enters the perineum through the lesser sciatic foramen.
- The obturator artery courses along the lateral pelvic wall and exits the pelvis through the obturator canal. In 30% of cases, the obturator artery is perfused from both internal and external iliac arteries, making angioembolization more complicated.
- The superior gluteal artery is the largest branch of the internal iliac artery. It exits the pelvis through the greater sciatic foramen above the piriformis muscle. It provides blood supply to gluteus medius and minimus muscles.
Surgical Anatomy
Severe bleeding in complex pelvic fractures usually originates from branches of the internal iliac artery, presacral venous plexus, fractured bones, and soft tissues. Major iliac vascular injuries are encountered in about 10% of patients with severe pelvic fracture.
The abdominal aorta bifurcates into the two common iliac arteries at the L4-L5 level. The iliac veins are located posterior and to the right of the common iliac arteries. The ureter crosses over the bifurcation of the common iliac artery as it branches into the external and internal iliac arteries.
The internal iliac artery is about 4 cm long. At the level of the greater sciatic foramen, it divides into the anterior and posterior trunks. It supplies numerous splanchnic and muscular branches and terminates as the internal pudendal artery, which is a potential source of hemorrhage in anterior ring disruptions. Hemorrhage following pelvic fracture can occur from any branch.
The most commonly injured internal iliac artery branches (in decreasing order of frequency) are the superior gluteal, internal pudendal, and obturator arteries.
The superior gluteal artery is the largest branch of the internal iliac artery. It exits the pelvis through the greater sciatic foramen above the piriformis muscle. It provides blood supply to gluteus medius and minimus muscles.
The internal pudendal artery passes through the greater sciatic foramen, courses around the sciatic spine, and enters the perineum through the lesser sciatic foramen.
The obturator artery courses along the lateral pelvic wall and exits the pelvis through the obturator canal. In 30% of cases, the obturator artery is perfused from both internal and external iliac arteries, making angioembolization more complicated.
General Principles
Any significant (>3 cm) pubic symphysis diastasis significantly increases the pelvic volume and reduces the effectiveness of tamponade of venous bleeding.
Complex pelvic fractures are associated with a high incidence of intra-abdominal injuries and significant blood loss. Nearly 30% of these fractures are associated with intra-abdominal injuries and 80% have multisystem trauma.
The most commonly associated intra-abdominal injuries involved the bladder and urethra, followed by the liver, small bowel, spleen, and diaphragm.
Patients with severe pelvic fractures should be admitted to the intensive care unit under general or trauma surgery for close monitoring for major bleeding or possible intra-abdominal injuries, for at least 24 hours, before transferring to an orthopedic service.
The hemorrhage in pelvic fractures originates from the fractured bone surfaces, pelvic venous plexus, the internal iliac artery branches (15–20%), and soft tissue injuries. Pelvic vascular injuries involving the major iliac veins and arteries occur in about 10% of severe fractures.
Independent predictors of severe hemorrhage from pelvic fractures include persistent hypotension, contrast extravasation on CT imaging, large pelvic sidewall hematoma, sacroiliac joint disruption, pubic symphysis diastasis >2.5 cm, bilateral and concomitant superior and inferior pubic rami fractures (“Butterfly fracture”), age ≥55 years, and female gender.
While the anteroposterior compression (i.e. open book pelvic) fractures are frequently associated with pelvic vascular injury and hemodynamic compromise, lateral compression fractures are often associated with injuries to the urogenital and the gastrointestinal structures.
A pelvic radiograph is useful in determining the need for or contraindication to application of a pelvic binder; pubic symphysis diastasis is an excellent indication for pelvic binder application, while a fracture of the iliac wing, severe acetabular fractures, and generally lateral compression fractures are contraindications because they might worsen the fracture displacement, pain and, perhaps, bleeding. However, a pelvic radiograph often underestimates the severity of the fracture and may miss posterior fractures.
Avoid intravenous access in the groin because of the possibility of an associated iliac venous injury.
Management of Pelvic Fracture Bleeding
The majority of patients with bleeding from pelvic fractures can safely be managed with supportive measures, such as pelvic immobilization and blood transfusions, while some require angioembolization. The massive transfusion protocol should be followed in the appropriate cases.
Pelvic binder is the first treatment to reduce the pelvic ring volume in open book pelvic fractures. The pelvic binder should be applied over the major trochanters to allow laparotomy and femoral artery access for catheter-based angiographic embolization.
Pelvic binder is contraindicated in major iliac wing fractures, complex acetabular fractures, and lateral compression fractures.
