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4. Basic Steps in Vascular Reconstructions
Blood vessel exposure
Blood vessel dissection
Tunneling
Anticoagulation
Blood vessel control
Creation of a blood vessel incision
Preparation of a patch or a bypass
Construction of the suture line
Securing hemostasis
Evaluating the vascular reconstruction
Blood Vessel Exposure
Vessel anatomy and exposure
Artery | Common exposure | Alternate |
|---|---|---|
Common carotid: origin and most proximal | Median sternotomy | |
Common carotid: distal and carotid bifurcation | Anterior border of sternocleidomastoid | Transverse neck |
Vertebral: origin | Supraclavicular incision | Anterior neck |
Subclavian | ||
Origin Rt | Median sternotomy | |
Origin Lt | Anterior thoracotomy (3rd intercostal space) | Trapdoor |
First part | Supraclavicular incision | |
Second part | Supraclavicular incision | |
Third part | Supraclavicular incision | |
Axillary | Infraclavicular incision | Axillary |
Brachial | Medial incision | |
Suprarenal aorta | Transabdominal medial visceral rotation (MVR) | Retroperitoneal Thoracoabdominal, (TA) |
Celiac | Transabdominal, MVR | Retroperitoneal, (TA) |
Superior mesenteric | Transabdominal, MVR | Retroperitoneal, (TA) |
Infrarenal aorta | Transabdominal | Retroperitoneal |
Common and external iliac | Transabdominal | Retroperitoneal |
Internal iliac | Transabdominal | Retroperitoneal |
Common femoral | Medial incision | Lateral incision |
Profunda | Medial incision | Lateral to sartorius |
Superficial femoral | Medial incision | Lateral to sartorius |
Popliteal | Medial incision | Lateral incision, Posterior approach |
Popliteal, below knee | Medial incision | Lateral incision with resection of fibula |
Peroneal | Medial incision | Lateral incision with resection of fibula |
Posterior tibial | Medial incision | Lateral incision with resection of fibula |
Anterior tibial | Lateral approach | Medial approach |
Blood Vessel Dissection
Blood vessels are usually dissected sharply using a blunt-tipped scissors . A 15 blade can also be used for the dissection and is especially valuable when dealing with scarred tissues in redo procedures. An inadvertent vascular incision caused by a knife may be easier to repair than a tear produced by a scissors. As the vessel is being exposed, self-retaining retractors are usually placed at progressively deeper levels, applying traction on the tissues to be divided. Retractors should be carefully applied to avoid injury to neighboring vessels or nerves. Once the vessel is adequately exposed, the adventitia on its anterior surface is carefully grasped with a Debakey forceps. While applying gentle traction on the adventitia and countertraction on the surrounding tissues, sharp dissection along the sidewall of the vessel will identify an avascular plane between the vessel and its surrounding tissues. This plane is developed on each side of the vessel and followed posteriorly to achieve circumferential dissection of the vessel. Although circumferential dissection may be appealing, it is not always necessary. For example, when exposing the infrarenal aorta during an aortic reconstruction, dissection on each side of the aorta down to the spine without circumferential dissection may be sufficient for achieving vascular control. Anterior exposure of the tibial vessels may be all that is needed when a pneumatic external tourniquet or an internal vessel occluder is used for vascular control. Similarly, circumferential dissection is not required when a partially occluding clamp is used to achieve vascular control.
Blood vessels can be traced proximally and distally, anticipating their cylindrical shape and adjacent vascular structures. Throughout the dissection, the vessels should be handled gently; only the adventitia should be grasped with the forceps. Grasping the full thickness of the vessel wall can cause intimal damage. Silastic vessel loops may be passed around a vessel and used for vessel retraction. However, only gentle traction on the vessel loop should be used to avoid damage to the vessel wall. The sites of major vascular branches can be anticipated from knowledge of surgical anatomy. Dividing arterial branches should be avoided, as they may represent important collateral channels.
Tunneling
Bypasses can be tunneled along the vessel being bypassed (anatomically) or extra-anatomically. When the tunnel is of a short distance, it can be created with the Metzenbaum scissors alone or in conjunction with blunt finger dissection. Tunneling devices can also be used to pass the graft from one location to another and are essential when the tunnel is of a long distance. Two different types of tunneling devices exist. In one type, the tunneling device is made of an outer tube and an inner obturator. Once the tunnel is created, the obturator is removed and a passer is used to grab the graft and pass it through the outer part of the tunneling device. In the other type, the tunneling device is made of one part with interchangeable heads of different dimensions. After creating the tunnel with the tunneling device, the graft is tied to the tunneller. By withdrawing the tunneller, the graft is pulled into the desired location.
Axillofemoral bypass : In the chest, the tunnel is created to pass anterior to the rib cage and posterior to the pectoralis major muscle. The graft is usually tunneled along the midaxillary line. The graft continues subcutaneously and crosses over the inguinal ligament medial to the anterior superior iliac spine. Adequate length should be available to avoid excessive tension on the proximal anastomosis to the axillary artery. Otherwise, a Y-deformity or, very rarely, disruption of the axillary anastomosis could occur. A counterincision may be required especially in large individuals. The counterincision is usually made halfway between the inguinal and the infraclavicular incisions.
Femorofemoral bypass : The tunnel in a femorofemoral bypass is subcutaneous. It can be started with the Metzenbaum scissors and further developed by blunt finger dissection or with the use of a C-shaped tunneller. A gentle C-curve is important to avoid kinking of the femorofemoral graft at the level of the femoral anastomosis. It is also important to tunnel just anterior to the fascia of the external oblique muscle and to avoid tunneling in a very superficial plane.
Aortobifemoral bypass : Tunneling for the limbs of the aortobifemoral bypass is usually accomplished with blunt finger dissection. One finger is introduced below the inguinal ligament over the external iliac artery. Another finger is introduced over the common iliac artery and advanced toward the inguinal ligament until both fingers meet. Care is taken to keep the tunnel posterior to the ureter. Otherwise, fibrosis and stricture of the ureter can develop in the future where the ureter is sandwiched between the iliac arteries and the graft limb. An aortic Debakey clamp can be introduced in the tunnel from the inguinal region toward the aorta to grasp and pull the graft limb through the tunnel.
Infrainguinal bypass : Except for an in situ bypass, infrainguinal grafts usually need to be tunneled. The tunnel can be subcutaneous, subfascial, or subsartorial. An advantage of a subcutaneous tunnel is the easy access to the graft should a revision become necessary. If skin flaps were developed during the dissection or vein harvesting, placing the bypass in a deeper subfascial or subsartorial location may be preferred, especially when the wound appears to be at increased risk for infection or nonhealing. The adductor canal is not usually used as a tunnel. Prosthetic grafts are infrequently placed subcutaneously.
Above-knee femoropopliteal bypass : A prosthetic graft is usually placed in a subsartorial or subfascial tunnel. An autogenous vein bypass is placed in a subcutaneous, subfascial, or subsartorial tunnel.
Below-knee femoropopliteal bypass : A prosthetic graft is usually tunneled subsartorially until the above-knee location. From the suprageniculate to the infrageniculate popliteal artery, tunneling behind the knee joint is usually achieved by blunt finger dissection. It is important to make sure that the tunnel is created between the heads of the gastrocnemius muscle; otherwise, an iatrogenic entrapment syndrome can develop. A similar tunnel can be used with an autogenous vein bypass. Alternatively, a subcutaneous or subfascial tunnel can be used.
The bypass to the above-knee popliteal artery is tunneled subsartorially. (A)
The bypass to the below-knee popliteal artery is tunneled subsartorially to the above-knee level and then tunneled anatomically behind the knee between the heads of the gastrocnemius muscle. (B)
The bypass to the posterior tibial artery is tunneled subsartorially and then subfascially or subcutaneously below the knee. (C)
The bypass to the anterior tibial artery is tunneled subsartorially above the knee and then through the interosseus membrane. (D)
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