Direct Surgical Repair of Aneurysms of the Infrarenal Abdominal Aorta and Iliac Arteries

Historical Background

Abdominal aortic aneurysms were first described by the sixteenth-century anatomist Vesalius. Before the advent of modern surgical techniques, numerous management methods focusing on aneurysm ligation, induced thrombosis, or wrapping were attempted, all with little success. It was not until 1951, when Dubost and associates performed the first successful abdominal aortic aneurysm repair using an aortic homograft, that the management of abdominal aortic aneurysms entered the modern era. That achievement prolonged the patient’s life by 8 years and stood in stark contrast to the dismal results associated with prior methods of treatment. The next major advance occurred in 1953, when Blakemore and Voorhees first used a prosthetic graft to repair an aortic aneurysm. Despite these early advances, operative mortality rates were approximately 20%. Subsequent improvements in anesthetic management and operative technique reduced mortality rates to between 4% and 9% by the 1970s. Chief among these advances was the adoption of the graft inclusion technique, as advocated by Creech. Refinements in preoperative cardiac evaluation and optimization, in addition to intraoperative cardiac and fluid management, have contributed to further reductions in perioperative mortality to less than 5%.

Preoperative Preparation

• Transabdominal ultrasonography is an excellent screening tool for determining the maximum diameter of an abdominal aortic aneurysm. Once the decision is made to proceed with repair, computed tomography (CT) angiography is essential for operative planning. Arteriography is seldom used in contemporary practice. However, in patients with extensive aortoiliac occlusive disease or a significant renal artery stenosis, catheter interventions may reduce the extent of open abdominal aortic aneurysm repair.

• Evaluation of cardiac risk is based on clinical history, electrocardiogram (ECG), and noninvasive testing in select patients deemed to be at high risk.

• An abdominal aortic aneurysm is an indicator of increased cardiovascular risk, and both perioperative statin and antiplatelet therapy are beneficial. Beta-blockade has also been thought to provide benefits, although recent publications have questioned this understanding.

• Prophylactic antibiotics, an intraoperative nasogastric tube, arterial blood pressure monitoring, a central venous catheter, a Foley catheter, large-bore intravenous access, and an epidural catheter are standard tenets in open aortic surgery.

Pitfalls and Danger Points

• Proximal and distal aortic control. A plan for the positioning of the aortic clamp and the extent of resection should be defined before operative intervention. The plan should be based on the surgical anatomy as determined by CT imaging.

• Venous injuries. To avoid injury to the renal vein, wide mobilization by ligation of renal vein branches is preferred, or if needed, the renal vein is divided close to the inferior vena cava with dependence on adrenal, gonadal, and renal lumbar vein branches for venous drainage. To minimize the risk of iliac vein or cava injury, dissection of the aorta and iliac arteries should be limited to noncircumferential, anterior, lateral, and medial exposure.

• Impaired distal perfusion.

  • Distal embolization. Manual retraction of the aneurysm sac during dissection of the aortic neck may be required but should be as gentle as possible with appropriate use of a lap pad. In addition, distal iliac clamps should be placed before the proximal aortic clamp.

  • Iliac artery clamp injury. To avoid an obstructing plaque, the iliac artery should be carefully palpated and assessed and the clamp should be positioned in a noncalcified portion of the vessel or angled so that the posterior plaque is compressed against the anterior wall rather than crushed.

• Retrograde ejaculation or impotence. To avoid retrograde ejaculation or impotence, the autonomic sympathetic fibers along the left side of the aortic bifurcation, inferior mesenteric artery, and left common iliac artery should be preserved, along with internal iliac artery flow.

• Intestinal injury. Preventing duodenal injury requires careful dissection of the third portion of duodenum off the proximal portion of aneurysm while avoiding thermal injury.

• Ureteral injury. The ureters are at risk for injury where they cross anterior to the distal common iliac arteries.

• Bowel ischemia. Maintenance of flow to at least one internal iliac artery is essential. Reimplantation of the inferior mesenteric artery should be considered if backbleeding is sluggish despite restoration pelvic flow, mesenteric Doppler signals are weak, and the sigmoid colon is dusky.

• Retraction injury. Self-retaining retractor traction injury is a risk for nerves or other structures, such as the spleen and superior mesenteric artery.

Operative Strategy

Division of the Renal Vein

Renal vein division is not necessary in most cases, especially with complete circumferential dissection of the renal vein and with ligation and division of the adrenal, gonadal, and renal lumbar branches that facilitate retraction of the renal vein ( Fig. 23-1 ). In the case of a reoperative field or suprarenal aneurysm, where the dissection is more challenging, division of the renal vein with an endoscopic vascular stapler can be helpful technique and is well tolerated.