Iliac Artery Injury

What the iliac arteries are

The abdominal aorta splits at about the level of the belly button into the left and right common iliac arteries. Each divides in the pelvis into:

• the external iliac artery, which runs along the pelvic rim and becomes the femoral artery in the groin, supplying the leg
• the internal iliac artery, which supplies the pelvic organs, buttock muscles and pelvic floor

These arteries lie deep in the retroperitoneum (the space behind the abdominal lining), next to the iliac veins, the ureters and the lower spine. Injury can cause bleeding that is hidden inside the pelvis, so a person can lose a large volume of blood before the cause is obvious.

Bleeding from the internal iliac branches is the usual source of arterial bleeding in a pelvic fracture; that topic is covered in detail on our internal iliac artery bleeding page.

Causes

Trauma

• Penetrating injuries: gunshot wounds cause most iliac artery injuries in civilian trauma. Stab wounds are less common.
• Blunt trauma: severe pelvic fractures, seat-belt injuries and crushing can tear the artery, rip its inner lining (intimal tear) or cause it to clot.

Medical procedures (iatrogenic injury)

• cardiac catheterization, angioplasty, aortic stent-grafts and heart valve procedures through the groin, especially with large sheaths in narrowed or calcified arteries
• lumbar spine surgery, particularly disc surgery at L4 to L5, where instruments can pierce the front of the disc
• hip replacement, especially revision surgery
• pelvic cancer surgery, gynecological surgery and laparoscopic port insertion
• radiotherapy to the pelvis, which can narrow arteries years later

Other

• Spontaneous dissection in connective tissue disorders or aortic dissection extending down
• External iliac endofibrosis: gradual thickening of the artery wall in elite cyclists from repetitive hip flexion, causing leg pain during maximal effort

Signs and symptoms

The picture depends on whether the artery is bleeding, blocked or both.

Bleeding (hemorrhage):

• signs of hemorrhagic shock: fast pulse, low blood pressure, pale cold skin, confusion
• swelling of the lower belly, flank or groin
• bruising in the flank or groin
• back, flank or pelvic pain from a retroperitoneal hematoma

Blockage (ischemia):

• the "6 Ps" in the leg: pain, pallor, pulselessness, paresthesia (pins and needles), paralysis and poikilothermia (coldness)
• later, muscle swelling that can lead to compartment syndrome

Diagnosis

1. Primary trauma survey: airway, breathing and circulation, with blood transfusion started for shock.
2. Physical exam: pulses in both groins and feet, comparing sides; an ankle-brachial index below 0.9 suggests an arterial injury.
3. FAST ultrasound and pelvic X-ray in the trauma bay.
4. CT angiography: the main test in stable patients. It shows active bleeding, blockage, dissection and associated injuries.
5. Catheter angiography: both a test and a treatment, allowing embolization or stenting in the same session.

Unstable patients with penetrating injuries go straight to the operating room.

Treatment

Survival depends on stopping the bleeding quickly and restoring blood flow to the leg within about 6 hours.

• Resuscitation: balanced blood product transfusion, tranexamic acid and keeping the patient warm. A pelvic binder is used for unstable pelvic fractures.
• Open surgical repair: direct suture of the artery, a patch, a vein or synthetic graft, or a bypass (such as femoral-femoral crossover) when the area is contaminated.
• Endovascular repair: a covered stent-graft placed through a catheter seals tears and dissections without opening the abdomen. It is increasingly used for blunt and procedure-related injuries.
• Embolization: blocking bleeding internal iliac branches with coils or particles, done by interventional radiology.
• Damage-control surgery: temporary shunts or ligation in critically ill patients, with definitive repair later.
• Fasciotomy: cutting the tight muscle compartments of the leg if swelling threatens the muscles after blood flow is restored.

Associated injuries to the iliac vein, bowel, bladder or ureter are common and repaired at the same time.

Complications and outlook

Iliac vascular injuries carry high mortality, largely from blood loss and the severity of other injuries; combined artery and vein injuries are the most dangerous. Procedure-related injuries recognized early usually have good outcomes with stenting. Possible complications include:

• leg amputation if blood flow is not restored in time
• graft infection, especially with bowel injury
• compartment syndrome and kidney injury from muscle breakdown
• late narrowing or blockage of the repair
• buttock claudication or erectile dysfunction after internal iliac embolization, usually when both sides are blocked

Frequently asked questions

What happens if the iliac artery is cut?

Blood loss is rapid and largely hidden inside the pelvis, so shock can develop within minutes. Without emergency surgery or a stent to seal the artery, it is often fatal. The leg on that side may also lose its blood supply.

What are the signs of an iliac artery injury after a procedure?

Watch for sudden back, flank or lower belly pain, a swelling groin, dizziness, fainting, a racing pulse or falling blood pressure in the hours after a catheter procedure or surgery. A cold, numb or painful leg suggests the artery is blocked.

How is an iliac artery injury repaired?

Options include open surgical repair with stitches, a patch or graft, a bypass around the damaged segment, or a covered stent placed through a catheter. Bleeding small branches of the internal iliac artery are often closed off with embolization.

Can you survive an iliac artery injury?

Yes, many people do, especially when the injury is recognized quickly and treated in a trauma center. Survival is lower with gunshot wounds, combined artery and vein injuries, and severe injuries elsewhere in the body.