Abstract
- The abdominal aorta bifurcates into the two common iliac arteries at the level of the fourth to fifth lumbar vertebrae (surface landmark is the umbilicus). The common iliac arteries are about 5–7 cm in length.
- At the level of the sacroiliac joint, the common iliac arteries bifurcate to the external and the internal iliac arteries.
- The external iliac artery runs along the medial border of the psoas muscle and goes underneath the inguinal ligament to become the common femoral artery. It gives two major branches: the inferior epigastric artery, just above the inguinal ligament, and the deep iliac circumflex artery, which arises from the lateral aspect of the external iliac artery opposite the inferior epigastric artery.
- The internal iliac artery is a short and thick vessel, about 3–4 cm in length. It divides into the anterior and posterior branches at the sciatic foramen. These branches provide blood supply to the pelvic viscera, perineum, pelvic wall, and the buttocks.
- The ureter crosses over the bifurcation of the common iliac artery.
- The common iliac veins lie medially and posterior to the common iliac arteries. They join to form the inferior vena cava at the level of the fifth lumbar vertebra, posterior to the right common iliac artery.
Anatomy of the Iliac Vessels
The abdominal aorta bifurcates into the two common iliac arteries at the level of the fourth to fifth lumbar vertebrae (surface landmark is the umbilicus). The common iliac arteries are about 5–7 cm in length.
At the level of the sacroiliac joint, the common iliac arteries bifurcate to the external and the internal iliac arteries.
The external iliac artery runs along the medial border of the psoas muscle and goes underneath the inguinal ligament to become the common femoral artery. It gives two major branches: the inferior epigastric artery, just above the inguinal ligament, and the deep iliac circumflex artery, which arises from the lateral aspect of the external iliac artery opposite the inferior epigastric artery.
The internal iliac artery is a short and thick vessel, about 3–4 cm in length. It divides into the anterior and posterior branches at the sciatic foramen. These branches provide blood supply to the pelvic viscera, perineum, pelvic wall, and the buttocks.
The ureter crosses over the bifurcation of the common iliac artery.
The common iliac veins lie medially and posterior to the common iliac arteries. They join to form the inferior vena cava at the level of the fifth lumbar vertebra, posterior to the right common iliac artery.
(b) Anatomy of the left iliac vessels. The common and external iliac veins run medial and posterior to the arteries.
General Principles
For effective control of the bleeding from the iliac arteries, the internal iliac artery should always be included because bleeding may persist despite proximal and distal clamping of the vessels.
Control of any enteric injuries and removal of enteric spillage should be done before definitive vascular reconstruction.
The presence of enteric contamination is not a contraindication for the use of synthetic grafts and there is no need for routine extraanatomical bypass procedures. Copious irrigation and washout of the peritoneal cavity before arterial reconstruction and tissue coverage with adjacent peritoneum or omentum reduces the risk of graft infection.
Extraanatomical bypass procedures are rarely indicated at the acute stage. They should be considered only in patients with graft infection.
Ligation of the common or external iliac arteries should never be done because of the high incidence of limb loss and systemic complications. In patients “in extremis,” a damage control procedure with a temporary shunt should be considered.
The internal iliac artery can be ligated with impunity.
Ligation of the common or external iliac veins is usually tolerated well. In most patients, there is transient leg edema, which resolves with elevation and elastic stockings. In rare cases, there is development of extremity compartment syndrome requiring fasciotomy.
Following arterial or venous injuries, the patient should always be monitored for extremity compartment syndrome. The combination of arterial and venous injuries is associated with a high risk of compartment syndrome, and these patients should be monitored closely. If continuous monitoring is not possible, liberal fasciotomy should be considered.
Venous repairs producing more than 50% are associated with a high incidence of pulmonary embolism. In these cases, consider ligation or a vena cava filter.