Townsend Courtney M.Jr., Evers B. Mark. Atlas of General Surgical Techniques: Expert Consult

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CHAPTER 82 • Resection of Abdominal Aortic Aneurysm 891

INFLAMMATORY ANEURYSM

◆ In approximately 5% of patients with abdominal aortic aneurysms, a dense ﬁ brotic reaction

involving the aortic wall and retroperitoneum is encountered. The inﬂ ammatory reaction

may involve the duodenum, inferior vena cava, left renal vein, and ureters and is manifested

as a thick white plaque overlying the aorta. Inﬂ ammatory aneurysm is an important cause of

abdominal pain in patients with abdominal aortic aneurysms that must be distinguished

from ruptured aneurysms on CT scans or MRI. These aneurysms are best repaired via the

retro peritoneal approach mobilizing the aorta above the renal vein, taking care not to dissect

the duodenum off the aneurysm wall. Venous anomalies such as left-sided or double inferior

vena cava should be identiﬁ ed and preserved.

◆ No attempt should be made to dissect the aorta or iliac arteries circumferentially to mini-

mize the risk of venous bleeding.

◆ Elective ligation and division of the left lumbar vein allows cephalad retraction of the renal

vein, reduces the risk of bleeding, and improves exposure.

◆ Large lymphatic vessels and the cisterna chyli are often present at the level of the renal vein

and should be suture ligated to prevent the rare occurrence of chylous ascites.

◆ Dissection of the left common iliac artery bifurcation should be undertaken by dividing the

lateral peritoneal attachments of the descending colon, thus avoiding injury to the hypogas-

tric nerves bilaterally. Routing the left limb of the graft through the lumen of the common

iliac artery also minimizes the risk of this complication.

◆ If the renal vein is not present in its usual anterior location, a retroaortic renal vein should

be suspected and care taken in placing the proximal clamp.

◆ Rectal bleeding in the early postoperative period should prompt careful sigmoidoscopy and

prompt return to the operating room if signiﬁ cant ischemia is present or acidosis persists.

SELECTED REFERENCES

1. Standring S (ed): Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 39th ed. Philadelphia,

Churchill Livingstone, 2005.

2. Lederle FA, Johnson GR, Wilson SE, et al: Prevalence and associations of abdominal aortic aneurysm de-

tected through screening. Ann Intern Med 1997;126:441-449.

3. Sicard GA, Reilly JM, Rubin BG, et al: Transabdominal versus retroperitoneal incision for abdominal aortic

surgery: report of a prospective randomized trial. J Vasc Surg 1995;21:174-181.

892

STEP 1: SURGICAL ANATOMY

SURGICAL ANATOMY OF THE FEMORAL REGION

◆ The inguinal ligament deﬁ nes the transition from the external iliac to the common femoral

artery. The common femoral artery and vein are encased in the femoral sheath in the proxi-

mal thigh bounded by the femoral triangle (Figure 83-1). The lateral boundary of this trian-

gle is formed by the sartorius muscle, the medial boundary by the adductor longus muscle,

and the cephalad base by the inguinal ligament.

◆ Just proximal to the inguinal ligament, the external iliac artery has two branches: the infe-

rior epigastric and the deep circumﬂ ex iliac arteries. Just distal to the inguinal ligament, the

common femoral artery has three branches: the superﬁ cial epigastric, the superﬁ cial cir-

cumﬂ ex iliac, and the superﬁ cial external pudendal arteries.

◆ The common femoral artery divides into the superﬁ cial and the deep femoral arteries as it

crosses the pectineus muscle. The superﬁ cial femoral artery traverses the thigh between the

quadriceps and adductor muscles in the adductor, or Hunter’s, canal. The origin of the deep

femoral artery is 3 to 5 cm distal to the inguinal ligament. This artery is crossed by the lat-

eral femoral circumﬂ ex vein (see Figure 83-1).

Aortofemoral Bypass Graft

for Occlusive Disease

Charlie C. Cheng and Michael B. Silva, Jr.

CHAPTER

CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 893

FIGURE 83 –1

Deep external

pudendal artery and vein

Superficial external

pudendal artery and vein

Great saphenous vein

Adductor longus muscle

Sartorius muscle

Superficial epigastric artery and vein

Ductus deferens

Inferior epigastric artery and vein

External iliac vein

Ureter

Testicular artery

Testicular vein

Superficial

circumflex iliac artery and vein

Genitofemoral nerve

External iliac artery

Deep femoral artery

Common femoral

artery and vein

Femoral nerve

Superficial

femoral artery and vein

Anterior lateral accessory

saphenous vein

Deep femoral

artery

Superficial

femoral artery

Superficial

femoral vein

Lateral circumflex

femoral artery

Common

femoral artery

External

iliac artery and vein

Medial circumflex

femoral artery

Medial circumflex

femoral vein

Lateral circumflex

femoral vein

894 Section XII • V

ASCULAR

SURGICAL ANATOMY OF THE ABDOMINAL AORTA

◆ The abdominal aorta has three large, unpaired midline branches that supply most organs:

the celiac, superior mesenteric, and inferior mesenteric arteries (Figure 83-2). The celiac

and superior mesenteric arteries arise at the level of the ﬁ rst lumbar vertebra. The

inferior mesenteric artery arises at the third lumbar vertebra.

◆ The renal arteries arise at the level of the disc between the ﬁ rst two lumbar vertebrae from

the lateral walls of the aorta (see Figure 83-2). The left-sided artery is usually slightly more

cephalad than the right. The renal arteries lie posterior to the corresponding veins on each

side. The left renal vein usually passes anterior to the aorta, whereas the right renal artery

passes behind the inferior vena cava. A retroaortic left renal vein is a relatively common

venous variant with an incidence of approximately 3%.

◆ The left renal vein serves as a landmark for cephalad dissection of the abdominal aorta.

Beneath this vein, the origins of the right and left renal arteries can be located.

STEP 2: PREOPERATIVE CONSIDERATIONS

◆ Indications for aortobifemoral bypass are symptomatic atherosclerotic occlusive disease of

the infrarenal aorta and both iliac systems, and peripheral atheromatous embolization (blue

toe syndrome). Symptoms of occlusive disease include claudication, rest pain, and tissue

loss. The presence of rest pain or tissue loss usually results from multilevel occlusive disease

involving both the aortoiliac segment and the infrainguinal segment. Seventy-ﬁ ve percent to

80% of these patients can initially be managed with treatment of the inﬂ ow aortoiliac dis-

ease without treatment of the distal infrainguinal disease. This is usually adequate for

patients with claudication or rest pain. However, in patients with tissue loss, the distal dis-

ease should also be treated to provide pulsatile ﬂ ow to the foot. Embolization from athero-

sclerotic plaques in the aortoiliac system requires exclusion of the native aortoiliac arteries,

even if the plaque lesions are not associated with hemodynamically signiﬁ cant stenoses.

◆ Up to 50% of patients with aortoiliac disease may have clinically evident coronary artery

disease. The 30-day operative mortality for this bypass has decreased from 5% to 8% in the

early 1970s to 2% in the past decade as a result of improved preoperative management of

coronary artery disease. Patients should routinely be evaluated preoperatively for the pres-

ence of coronary artery disease and pulmonary, renal, and coagulation disorders.

◆ Preoperative imaging is needed in the evaluation of the entire abdominal aorta, the bilateral

iliac arteries, and down to the origins of the deep femoral arteries. Arteriography has histor-

ically been the main imaging modality. Other contemporary alternatives include magnetic

resonance imaging and computed tomography angiography. Complete bilateral lower

extremity arteriography is also recommended.

CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 895

FIGURE 83 –2

Right middle

adrenal artery

Right

adrenal vein

Left middle adrenal artery

Right and left inferior phrenic arteries

Left superior

adrenal artery

Right inferior

adrenal artery

Inferior

vena cava

Testicular, ovarian

artery and vein

Right superior

adrenal artery

Left adrenal

vein

Left inferior

adrenal artery

Aorta

Left inferior

phrenic vein

896 Section XII • V

ASCULAR

STEP 3: OPERATIVE STEPS

1. INCISION

◆ The patient is placed supine, and the abdomen, groin, and thighs are prepared and draped.

A narrow perineal towel is used, ensuring that it does not extend laterally to the groins. The

perineum should remain excluded from the surgical ﬁ eld throughout the procedure. A

povidone-iodine (Betadine)–impregnated self-adherent drape can be used to cover the

abdomen, perineal towel, and groin areas to prevent the towel from becoming loose on the

medial side of the femoral incisions.

◆ The groins are opened through vertical incisions directly over the femoral pulse, crossing

the inguinal crease to expose the femoral arteries (Figure 83-3). The incision is made with

one third of the incision above the inguinal ligament, and two thirds below it. If femoral

pulse is not palpable, the vertical incision is made slightly medial to the midpoint of the

inguinal ligament.

◆ The abdomen is opened through a full midline incision from the xiphoid process to the

symphysis pubis. The peritoneal cavity is entered through the linea alba, and the abdominal

aorta is exposed (see Figure 83-3). Alternatively, a retroperitoneal incision may be used.

This may be the approach of choice in patients with a hostile abdomen from previous

abdominal or aortic surgeries and poor pulmonary function. This incision is started from

the lateral border of the rectus muscle, 2 cm below the level of the umbilicus, and is

extended laterally to the tip of the 12th rib.

2. DISSECTION

◆ Femoral artery exposure

◆ The groin incisions are deepened and extended proximally to the inguinal ligament. The

fascia lata is opened along the medial margin of the sartorius muscle to expose the femo-

ral sheath underneath. This sheath is opened to access the common femoral artery, and

the artery is easily dissected free by separating the areolar tissue.

◆ The common femoral artery branches into the superﬁ cial and deep (profunda) femoral

arteries. The superﬁ cial femoral artery is exposed by dissecting distally from the common

femoral artery on its anterior surface. The deep femoral artery often originates 3 to 5 cm

distal to the inguinal ligament on the posterior lateral surface of the common femoral

artery. The lateral femoral circumﬂ ex vein crosses anteriorly to the deep femoral artery,

and caution should be used during dissection of this artery to avoid venous injury (see

Figure 83-1).

◆ The femoral arteries are examined for atherosclerotic occlusive disease and their suitabil-

ity for distal anastomosis. The common, superﬁ cial, and deep femoral arteries are each

encircled with tapes or vessel loops for control.

◆ Abdominal aorta exposure

◆ Following the exploration of the abdomen for any incidental pathology, the transverse

colon and the omentum are retracted upward toward the chest and protected from

retraction injury. The small bowel is gathered and retracted to the patient’s right side and

wrapped in a moist laparotomy towel.

CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 897

FIGURE 83 –3

Line of incision

Inferior vena cava

Site of anastomosis

of graft

Abdominal aorta

Inferior mesenteric artery

Left renal vessels

Line of

incision

External iliac artery

External iliac vein

Common

femoral artery

Common

femoral artery

Superficial

femoral artery

Deep

femoral artery

Deep

femoral vein

Deep femoral

artery

Superficial

femoral artery

Great

saphenous

vein

898 Section XII • V

ASCULAR

◆ The peritoneum is opened over the upper part of the aorta, and the ligament of Treitz is

divided to mobilize the fourth portion of the duodenum and the ﬁ rst part of the jeju-

num. The patency of the celiac axis and the superior and inferior mesenteric arteries are

conﬁ rmed by palpation.

◆ The aorta is exposed proximally to the left renal vein and distally to the inferior mesen-

teric artery using both sharp dissection and electrocautery of the small veins in the retro-

peritoneal tissue (Figure 83-4).

◆ The aorta is dissected free using blunt ﬁ nger dissection or a curved instrument just below

the left renal vein. The left renal vein is usually anterior to the aorta but can occasionally

be retroaortic. Failure to accurately identify the left renal vein may result in iatrogenic

injury during aortic cross-clamping.

◆ Aortofemoral bypass tunnel

◆ The tunnel is used to connect the exposed aorta from the abdomen and the femoral

arteries in the groins. It follows the course of the iliac and femoral arteries, lying anterior

to the arteries and posterior to the ureter. This prevents compression of the ureter by the

graft. The graft is protected in the retroperitoneal tissues.

◆ Tunneling is started from the groin incision, with blunt ﬁ nger dissection along the ante-

rior surface of the common femoral artery. The inferior epigastric and deep circumﬂ ex

iliac veins course anterior to the external iliac artery, and caution is used. These veins are

routinely divided and ligated under direct vision to preclude inadvertent avulsion.

◆ In the abdomen, tunneling is started on the anterior surface of the aortic bifurcation and

continued onto the common iliac artery. The ﬁ nger is passed blindly to meet with the

ﬁ nger advancing from the groin incision (Figure 83-5). The tunnel tract is maintained

with passage of umbilical tape. The patient is systemically treated with anticoagulants,

usually with unfractionated heparin, after the tunnel has been dissected and inspected

for hemostasis.

CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 899

FIGURE 83 –4

Proximal jejunum

Abdominal aorta

Abdominal bifurcation

Bilateral groin incision

Inferior vena cava

Colon

FIGURE 83 –5

Creating tunnel through

groin incision

900 Section XII • V

ASCULAR

◆ Aortic anastomosis

◆ The diameter of the aorta just below the left renal vein is assessed, and the size of the

bifurcated prosthetic graft is chosen. The typical location of the proximal anastomosis is

approximately 1 to 2 inches below the renal arteries. The aorta can be partially clamped

or cross-clamped below the renal arteries.

◆ The aortic limb of the aortic bifurcation graft is trimmed so that after the aortic anasto-

mosis, the two limbs lie in a natural position through the tunnels in the pelvis and exit

into the groin anterior to the femoral arteries. If the common trunk is too long, there is a

risk of kinking of the two limbs, compromising ﬂ ow.

◆ The proximal aortic anastomosis can be performed in an end-to-end or end-to-side fashion.

The end-to-end technique is used for patients who will not suffer circulatory compromise

from interruption of prograde ﬂ ow in the abdominal aorta. The end-to-side technique is

used for patients who require prograde ﬂ ow to perfuse an important hypogastric or inferior

mesenteric artery.

◆ For an end-to-side anastomosis, an arteriotomy is made on the aorta just below the renal

vein, and the anastomosis is sutured with a running technique using a 3-0 nonabsorbable

monoﬁ lament suture (Figure 83-6). The suture can be tightened with a nerve hook.

◆ For an end-to-end anastomosis, the aorta is divided sharply and the distal segment is

oversewn with a heavy suture (3-0 nonabsorbable monoﬁ lament) using mattress stitches,

followed by a second row using a running stitch over the cut edge. The graft is then

anastomosed to the proximal aortic segment (Figure 83-7).