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

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CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 901

FIGURE 83 –6

Left renal vein

Suture in posterior

anastomosis

Graft

FIGURE 83 –7

Suture in posterior

row of anastomosis

Left renal vein

Abdominal aorta

Graft

902 Section XII • V

ASCULAR

◆ After the aortic anastomosis is completed, the clamp is released for several beats to ﬂ ush

clots, debris, and air. The limb to be used ﬁ rst is then ﬂ ushed with heparinized saline. An

aortic clamp is placed through the tunnel from the groin, and the limb is pulled out of

the abdominal cavity (Figure 83-8).

◆ A plaque-free area in the distal common femoral artery is selected, and the artery is

opened on the anterior surface. The length of the limb is trimmed, and the end of the

graft is beveled. The anastomosis is performed with a 5-0 nonabsorbable monoﬁ lament

suture, starting at the heel (Figure 83-9).

◆ Before the anastomosis is completed, the limb is ﬂ ushed by removing the clamp from the

limb, and the aortic clamp is released. The anastomosis is completed, and the ﬂ ow is

restored ﬁ rst to the common femoral artery and allowed to retrogradely ﬁ ll the iliac artery

in the pelvis so that debris is swept into this vessel rather than toward the feet. The super-

ﬁ cial and deep femoral arteries are then reopened to restore ﬂ ow to the lower extremity.

◆ The procedure is repeated for the other limb.

3. CLOSING

◆ The retroperitoneal tissue is closed over the graft to separate it from the viscera to prevent

future adhesion or erosion of bowel. If this tissue is insufﬁ cient, the omentum can be used

by bringing it around the left side of the colon and tacking it down on top of the graft. The

bowel is returned to the abdominal cavity, and the nasogastric tube location is reconﬁ rmed

in the mid-portion of the stomach. The abdominal wall is closed using standard technique.

◆ The groin wound is closed in multiple layers with interrupted and/or running adsorbable

2-0 and/or 3-0 sutures using standard technique.

CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 903

FIGURE 83 –8

Graft

Adominal aorta

Left renal artery

Common

femoral artery

FIGURE 83 –9

Common

femoral artery

Graft

Deep

femoral artery

904 Section XII • V

ASCULAR

STEP 4: POSTOPERATIVE CARE

◆ Patients are monitored in the intensive care unit immediately after surgery for several days

and then transferred to the ﬂ oor unit. Most patients are discharged on their seventh or

eighth postoperative day.

◆ The nasogastric tube is removed with return of bowel function, usually on the third or

fourth postoperative day.

◆ Patients are assisted by physical therapists for early mobilization with ambulation. Aggres-

sive use of incentive spirometry is encouraged. Deep vein thrombosis prophylaxis is used.

◆ Patients are discharged when they have good pain control, exhibit return of bowel function,

and are ambulatory.

◆ Surveillance of the bypass graft patency uses clinical cues, such as pulse examination, and

objective criteria such as ankle-brachial indices (ABIs). Distal perfusion to the feet is veriﬁ ed

in the operating room before closure of the wounds. Any unexpected ﬁ ndings require imag-

ing and possible embolectomy. ABIs are followed in the postoperative period, at the ﬁ rst

postdischarge clinic visit, and then at 6-month intervals.

◆ Initial graft patency rates are nearly 100%. The 5-year patency rates range from 80% to

90%. Long-term patency rate at 10 years is approximately 75%.

◆ Complications include pelvic ischemia caused by interruption of pelvic blood ﬂ ow. Patients

may develop colon ischemia, neurologic deﬁ cit from lumbar ischemia, and infarction of the

pelvic musculature and skin.

◆ Embolization of large atheromatous debris may cause occlusion of major named vessels. Micro-

scopic debris may cause injury ranging from minor focal toe ischemia to extensive tissue loss

involving the major muscle groups of the buttocks, thigh, and leg.

◆ Other complications include lower extremity ischemia, male sexual dysfunction, and

wound infection. Long-term complications include anastomotic pseudoaneurysms or steno-

ses. The most serious complication is aortic graft infection with development of aortoenteric

ﬁ stula. Patients with this complication may present with acute gastrointestinal bleeding or

chronic anemia.

STEP 5: PEARLS AND PITFALLS

◆ The lateral femoral circumﬂ ex vein is located between the origins of the superﬁ cial femoral

and deep femoral arteries. Injury to this vein should be avoided during dissection of the

deep femoral artery. When the vein is identiﬁ ed, it may be ligated to provide direct access

to the deep femoral artery.

CHAPTER 83 • Aortofemoral Bypass Graft for Occlusive Disease 905

◆ The inferior epigastric and deep circumﬂ ex iliac arteries and veins can be found on the

anterior surface of distal external iliac or proximal common femoral arteries beneath the

inguinal ligament. Injury to these branches should be avoided during proximal dissection

of the common femoral artery. Tunneling from the groin wound should be performed under

direct visualization.

◆ In men, distal dissection should avoid the ﬁ broareolar tissue on the anterior surface of the left

common iliac artery. This tissue contains the autonomic nerves that control sexual function.

Extended dissection can lead to nervous disruption and resultant retrograde ejaculation.

◆ The left renal vein anterior to the aorta can be divided to facilitate aortic exposure.

◆ A large pulsatile artery next to the inferior mesenteric artery on the left side of the aorta is

likely a meandering mesenteric artery. This artery provides collateral circulation in the pres-

ence of mesenteric occlusive disease of the celiac or superior mesenteric artery, or both, and

should not be divided.

◆ Interruption of pelvic blood ﬂ ow should be avoided. The use of end-to-end or end-to-side

aortic anastomosis is determined by preoperative arteriography of the abdominal aorta and

bilateral iliac arteries. The end-to-end technique is used for patients who are not dependent

on 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.

◆ The deep femoral artery can serve as the only outﬂ ow despite complete occlusion of the

superﬁ cial femoral artery from atherosclerotic disease. The deep femoral artery is a low-

resistance vessel that is usually free of atherosclerotic disease beyond its secondary

branches.

◆ The common trunk of the bifurcated graft should be short, approximately 3 or 4 cm. This

facilitates coverage of the graft with retroperitoneal tissue to separate the anastomosis from

the overlying viscera. This also reduces the chance of kinking the graft limbs by decreasing

the angle at the bifurcation.

◆ Proximal anastomosis on the aorta is performed just distal to the origins of the renal arter-

ies. The infrarenal aorta can be affected by disease progression from atherosclerosis and

later compromise graft patency.

SELECTED REFERENCES

1. Zarins C, Gewertz B: Atlas of Vascular Surgery, 2nd ed. Philadelphia, Churchill Livingstone, 2005.

2. Valentine RJ, Wind GG: Anatomic Exposures in Vascular Surgery, 2nd ed. Philadelphia, Lippincott

Williams & Wilkins, 2003.

3. Moore WS: Vascular and Endovascular Surgery: A Comprehensive Review, 7th ed. Saint Louis, Saunders,

2006.

4. Zelenock GB, et al: Mastery of Vascular and Endovascular Surgery, 4th ed. Philadelphia, Lippincott

Williams & Wilkins, 2005.

906

STEP 1: SURGICAL ANATOMY

◆ The carotid sheath and its contents—including the extracranial carotid artery, the internal

jugular vein, and the vagus nerve—are located in the anterior triangle of the neck, which is

bounded by the mandible, the midline, and the strap muscles. Successful carotid endarter-

ectomy requires a thorough understanding of the anatomy of the anterior triangle, in partic-

ular because a number of cranial nerves are located in the area and are easily injured if care

is not taken to identify and preserve them.

◆ Figure 84-1 demonstrates the structures found in the anterior triangle of the neck. The

venous anatomy is variable. In the most commonly found situation, the anterior facial trib-

utary crosses anterior to the carotid arteries at the level of the common carotid bifurcation

and joins the internal jugular vein.

◆ The common carotid artery in the cervical region has no branches other than the external

and internal carotid arteries. The internal carotid artery in this region also has no branches,

except in rare situations. The persistent hypoglossal artery, a fetal structure that normally

regresses before birth, is found in less than 0.1% of cases. The external carotid artery most

commonly has three branches in the immediate region of the carotid bifurcation—the supe-

rior thyroid, lingual, and facial—although this anatomy can also be highly variable (see

Figure 84-1, A and B).

CHAPTER

Carotid Endarterectomy

Lois A. Killewich

CHAPTER 84 • Carotid Endarterectomy 907

Sternocleidomastoid

muscle

Clavicle

Sternum

Strap

muscles

Mandible

triangle

Midline

External carotid

artery

Facial artery

Digastric muscle

Lingual artery

Superior thyroid

artery

Hypoglossal

nerve

Common

carotid artery

Vagus nerve

Sternocleidomastoid (cut)

Sternocleidomastoid (cut

)

Clavicle

Omohyoid muscle

Ansa cervicalis

Anterior facial

vein (ligated)

Internal carotid

artery

Internal jugular

vein

FIGURE 84 –1

908 Section XII • Vascular

STEP 2: PREOPERATIVE CONSIDERATIONS

◆ Standard indications for carotid endarterectomy include a stenosis of 50% or higher in a

patient with a transient ischemic attack or stroke thought to originate from internal carotid

artery plaque and 60% to 80% stenosis in an asymptomatic patient. Recurrent stenosis,

stenosis secondary to radiation therapy, and high-risk patients with severe coronary artery

or pulmonary disease are often treated with carotid stenting.

◆ Carotid endarterectomy can be safely performed with the patient under general, regional,

or local anesthesia. Whichever technique is selected, a method must be used to ensure that

the patient has adequate intracranial blood ﬂ ow while ﬂ ow through the operated internal

carotid artery is interrupted. When local or regional anesthesia is used, the patient’s neuro-

logic status can be monitored by assessing contralateral motor function and, in some cases,

speech. Many surgeons use a squeeze toy in the contralateral hand and instruct the patient

to squeeze the toy to demonstrate that neurologic function is maintained when the carotid

arteries are clamped. If general anesthesia is used, neurologic function can be monitored

by measuring carotid back-pressure (the internal carotid artery pressure with the common

and external carotid arteries; a mean arterial pressure of 25 to 40 mm Hg is sufﬁ cient), by

using electroencephalographic or evoked potential monitoring, or by using routine carotid

shunting.

◆ Patients should be administered 325 mg of aspirin by mouth daily, starting before the surgi-

cal procedure. In selected instances, clopidogrel (75 mg by mouth daily) may be used in

addition to or in place of aspirin.

STEP 3: OPERATIVE STEPS

1. INCISION

◆ The head should be positioned with the neck hyperextended and rotated to the contra-

lateral side. This can be facilitated by placement of a rolled sheet between the shoulder

blades. The standard incision is placed along the medial border of the sternocleidomas-

toid muscle. The superior aspect should be extended posteriorly to the ear to ensure

against division of the greater auricular nerve (Figure 84-2, A).

◆ For a more cosmetically pleasing result, the incision can be created in a mid-cervical skin

crease, with an extension superiorly toward the ear (Figure 84-2, B).

CHAPTER 84 • Carotid Endarterectomy 909

Incision

for carotid

endarterectomy

Alternative

incision for carotid

endarterectomy

FIGURE 84 –2

910 Section XII • Vascular

2. DISSECTION

◆ After the incision is created, the platysma muscle is divided with electrocautery parallel to

the skin incision. If the cervical skin crease incision is used, ﬂ aps must be created deep

to the platysma muscle and extended superiorly toward the mandible and inferiorly toward

the clavicle. This can be accomplished using a combination of electrocautery and blunt

dissection, which enlarges the operative ﬁ eld to allow the dissection to be continued in

standard fashion.

◆ The dissection is deepened along the medial border of the sternocleidomastoid muscle until

the carotid sheath is identiﬁ ed (Figure 84-3). Small arteries and veins, which extend across

the dissection line to supply the sternocleidomastoid muscle, are cauterized. The

carotid sheath is opened using sharp dissection. (I prefer 7-inch Potts-Smith scissors, but

either Metzenbaum or tenotomy scissors can also be used.)

◆ Once the sheath is opened, the dissection of the carotid arteries is completed using scissors

(Figure 84-4). The common carotid artery is dissected ﬁ rst, followed by the external

carotid artery and the superior thyroid artery. It is generally not necessary to continue the

dissection of the external carotid artery beyond the second branch, which may be the lingual

artery or a combined trunk of the lingual and facial arteries. Once this dissection is com-

pleted, anticoagulants are administered to the patient systemically, usually with unfraction-

ated heparin at a dose of 100 units/kg body weight. The dissection of the internal carotid

artery is completed while the heparin is circulating, which provides some measure of protec-

tion from embolization of plaque from the internal carotid artery during the dissection.

When the dissection is completed, the arteries are controlled with vessel loops, sutures, or

Rumel tourniquets.

3. DETERMINING THE NEED FOR INSERTION OF A SHUNT

◆ The dissected vessels are clamped so that the need for shunting can be determined. Except

in the case of back-pressure monitoring, the internal carotid artery beyond the area of

plaque is clamped ﬁ rst to prevent embolization into the intracranial circulation. I prefer a

Gregory bulldog for clamping of the internal carotid artery; other choices include a Yasargil

aneurysm clip or a small vascular clamp such as a Karchner. The common and external ca-

rotid arteries are also clamped with small vascular clamps; branches of the external carotid

artery can be controlled with Yasargil clips, hemoclips, or Pott’s knots.

◆ If back-pressure monitoring is used to determine the need for shunting, the internal carotid

artery is not clamped. A 19-gauge butterﬂ y needle or a small angiocatheter connected to pres-

sure tubing is inserted into the artery distal to the plaque. It is imperative that this tubing be

ﬂ ushed thoroughly with heparinized saline before insertion to prevent introduction of air into

the carotid, and hence intracranial, circulation. The back-pressure is then measured; I use a

cutoff of 40 mm Hg mean arterial pressure to determine the need for insertion of a shunt.