Lower Extremity Arterial Exposure

Longitudinal Approach

The CFA is usually exposed through a longitudinal incision over the femoral pulse just distal to the inguinal ligament. If no pulse is present, the artery is usually still palpable as a firm, cylindrical mass slightly medial to the midpoint of the inguinal ligament. The incision should be extended proximally to expose the inguinal ligament. The length of the incision varies based on the patient’s body habitus and the extent of atherosclerotic disease, but typically about one-quarter to one-third of the incision should extend proximal to the ligament and the remainder distally. In very obese patients with a large overhanging pannus, it is important to identify the exact location of the inguinal ligament prior to making an incision. Often it is much more proximal than it may appear, making it possible to keep the distal end incision proximal to the fold in the pannus, which avoids the troublesome wound separation that invariably occurs when a vertical incision needlessly crosses this point. The subcutaneous tissue should be divided directly over the artery to avoid the creation of a medial or lateral flap, which can also lead to troublesome and occasionally disastrous problems with wound healing. Any small venous or arterial branches of the superficial epigastric and superficial circumflex artery encountered should be ligated and divided. The authors also routinely ligate any divided lymphatics to minimize lymphatic leaks. The saphenous vein typically lies medial to the artery but is often encountered. Care should be taken to extend the dissection lateral to its course to prevent its injury.

The fascia lata lies deep to the subcutaneous tissue and is divided medial to the medial edge of the sartorius muscle over the artery to enter the femoral sheath. Most commonly, exposure will extend to the inguinal ligament. If more proximal exposure is needed, the inguinal ligament can be mobilized and retracted superiorly to increase visibility. Additional exposure can be obtained by dividing the ligament, which must always be repaired at the time of closure. If extended exposure of the proximal SFA is needed, the sartorius muscle can be mobilized and retracted laterally. The DFA typically arises somewhat lateral and posterior to the CFA (see below). Care must be taken to avoid straying too far posterior and lateral to the CFA, which would risk injury to the femoral nerve. Medially, the common femoral vein is in very close proximity and not uncommonly adherent to the CFA. Careful sharp dissection is required to avoid its injury, especially in redo dissections.

Transverse Approach

The transverse approach is useful provided that only limited arterial exposure is needed, as for femoral embolectomy or a cutdown for endovascular aneurysm repair (EVAR). It begins with a horizontal skin incision 2 fingers’ breadth above to the groin crease, parallel to the inguinal ligament. Once the incision has been made, it is deepened through subcutaneous tissue and Scarpa’s fascia until the inguinal ligament is encountered. The ligament should be freed and mobilized to allow retraction superiorly. The dissection is deepened directly over the femoral pulsation until the femoral sheath is encountered, which is then incised longitudinally to expose the CFA. Self-retaining retractors are essential for adequate exposure. Although most of the CFA can usually be exposed through this approach, it provides only limited access to the superficial and deep femoral arteries.

Conventional (Proximal) Approach

The DFA originates approximately 2 to 5 cm distal to the inguinal ligament and has a lateral course relative to the CFA in most patients. Exposure of the DFA begins with longitudinal exposure of the CFA, as previously described. As the CFA is exposed distal to the inguinal ligament, the origin of the DFA is usually encountered on the lateral or posterior lateral side of the CFA at the point where the CFA caliber becomes noticeably smaller as it bifurcates into the DFA and SFA. In most cases a few centimeters of the DFA can be exposed before the lateral femoral circumflex vein is encountered ( Fig. 58.2 ); it crosses over its anterior surface and must be carefully divided and suture-ligated for additional exposure. Further dissection may require division of other crossing veins and lateral retraction of the sartorius muscle. Lymphatics are often encountered in extended exposure of the PFA and should be ligated. The femoral nerve is in close proximity and care should be taken to avoid its injury. The length of the proximal profunda varies from a few to as many as 8 cm. Branch points and bifurcations increase in frequency with more distal exposure. Both the medial and lateral circumflex arteries most commonly originate from the DFA, although either or both can originate from the CFA, usually near the DFA origin; they may be injured during careless posterior dissection of the CFA or DFA.

Lateral (Distal) Approach

The lateral approach to the DFA is useful in reoperative surgery as an alternative source of either inflow or outflow when the more proximal femoral vessels are encased in dense scar and/or infection or when a more distal inflow site is needed in the case of limited venous conduit. ^, The incision is made parallel to the course of the sartorius muscle usually 6 or 7 cm distal to the femoral pulsation or just distal to the end of a previous femoral incision. It can be placed on either the medial or lateral side of the sartorius depending on the situation and the likely course of the bypass graft; for example, lateral for a profunda–anterior tibial or axillary–profunda graft or medial for a femoral–profunda or profunda–popliteal graft ( Fig. 58.3 ). Regardless of the chosen incision, approaching the distal PFA requires dissection lateral to the superficial femoral vessels and adjacent nerves, which can be easily injured with retraction, especially when Gelpi or sharp-toothed Weitlaner retractors are being used. The dissection continues deep to the superficial femoral vessels in a plane between the vastus medialis and adductor longus muscles ( Fig. 58.4 ). Usually a raphe created by the intersecting fibers of the fascia of these muscles is encountered, which, when opened, exposes the underlying deep femoral vein. The artery is usually found deep to the vein. In difficult cases, a handheld Doppler probe is useful for identifying the location of the artery.

Proximal Approach

The SFA lies in a plane deep to the sartorius muscle, crossing over the adductor longus muscle. The proximal SFA is easily exposed by distal extension of the longitudinal incision made for exposure of the CFA. The SFA is located under the proximal sartorius muscle, which can be mobilized and retracted laterally. It can also be exposed in this fashion without exposing the CFA or DFA with a more distal incision placed along the anterior edge of the sartorius muscle (see below).

Mid/Distal Approach

The SFA follows a course between the anterior and medial compartments of the thigh in an aponeurotic tunnel, the adductor (Hunter) canal, created by components of the investing fascia of the vastus medialis, sartorius, and the adductor longus muscles. ^, In addition to the SFA, the Hunter canal contains the femoral vein deep to the artery and two branches of the femoral nerve: the sensory saphenous nerve and the motor nerve to the vastus medialis muscle. To approach the SFA, the patient is placed with the leg externally rotated and the knee flexed to 30 degrees. A longitudinal incision is then made parallel to the anterior border of the sartorius to avoid disrupting the blood supply to the muscle, which enters on its inferomedial edge. The incision is carried down to the fascia lata, which is incised to expose the sartorius muscle. The muscle is then reflected in a posterior direction to reveal the roof of the Hunter canal. The fascia is opened to expose the SFA and vein. The vessels are often densely adhered to one another requiring careful dissection to separate them. Typically several large branches of the vein are encountered crossing over the artery, which should be divided. The SFA, even when widely patent on imaging, usually has some degree of atherosclerosis and is often calcified. In the authors’ experience, the surgeon should be prepared to extend the initial exposure either proximally or distally to find the most suitable area for clamping and/or placing an anastomosis.