Avoid injury to phrenic nerve, brachial plexus, and vertebral arteries. The proximal left subclavian artery is approached using a high (3rd intercostal space) anterolateral thoracotomy and the innominate and proximal right subclavian artery through a median sternotomy and supraclavicular incision. The innominate vein can be ligated and divided to facilitate exposure to the innominate artery. Alternatively, the mid and distal subclavian arteries on both sides can be exposed through a supraclavicular incision or combined supraclavicular/infraclavicular incisions. There is no requirement to obtain proximal vascular control within the surgical field of injury; using separate incisions through non-traumatized tissues can expedite rapid vascular control. When approaching this injury, the operator should err on the side of ample proximal exposure and if necessary, can resect the clavicular head. In an unstable patient it is recommended that initial proximal control be obtained via thoracotomy as this will allow for more rapid control than use of the supraclavicular approach. Because of the technical challenges with exposure, the utility of temporary vascular shunts in this injury pattern is limited. Most often interposition graft using 6-8 mm ePTFE or Dacron is required for subclavian artery repair, being mindful of the vertebral artery and the phrenic nerve. If endovascular capability is available, balloon occlusion of the proximal subclavian artery can be a useful adjunct, and repair with a covered stent can be considered.1,2 (see Appendix E)
Brachial Artery Exposure
The brachial artery with the median nerve rests in the brachial sheath and is exposed through a medial incision in the upper arm in the groove between the bicep and triceps (see below). The median nerve is the most superficial structure encountered upon entering the brachial sheath. The ulnar nerve runs posterior to the artery which is surrounded by paired deep brachial veins. A common anatomic variant is for there to be a high bifurcation of the brachial artery in the upper third of the arm. Repair is most commonly accomplished using a reversed saphenous vein interposition graft. Although it may be possible to ligate the brachial artery below the origin of the deep (profunda) brachial artery and maintain a viable arm and hand, this proposition is based on intact collateral circulation. Unfortunately, collaterals from the shoulder and deep brachial artery are often damaged in the setting of penetrating or blast wounds and therefore maintenance of flow through the brachial artery with a temporary shunt or vascular repair is advised. Ligation or primary amputation is an acceptable damage control maneuver if there is not time for shunting or the patient is in extremis.
Most often the hand has a dual arterial supply and therefore can tolerate ligation of either the radial or ulnar artery. As such, repair, or reconstruction of an injury at this level is rare. Perfusion to the hand should be assessed with Doppler before and after occlusion or ligation, and if the absence of a signal persists, reconstruction with reversed saphenous vein should be performed. Given the relatively small muscle mass of the hand and the degree of collateral circulation, ligation is most often tolerated understanding that if ischemia persists, evaluation and revascularization can be performed at a CONUS facility days or weeks later.
Injury to the common femoral artery is often fatal as hemorrhage control in the field is difficult. Exposure is obtained through a single longitudinal incision above the artery (2-3 cm lateral to the pubic tubercle) exposing the artery at the inguinal ligament. A key point in exposing the femoral artery is ensuring there is adequate and reliable proximal and distal control prior to exploring the injury. Placing the incision proximal enough so that the abdominal wall and inguinal ligament can be identified first in a consistent and familiar location (oftentimes by drawing a line from the anterior superior iliac spine to the pubic tubercle on the skin prior to incision). Alternatively, proximal control can be obtained in the retroperitoneum (i.e. external iliac) through the proximal extension of this groin incision or by using a limited transverse incision in the lower abdomen. After a transverse-oblique skin incision, the external and internal oblique aponeuroses are divided, and the lateral fibers of the internal oblique separated. The transversus muscle and transversalis fascia are opened allowing entrance into the retroperitoneum, and the peritoneum is reflected cephalad, exposing the internal iliac vessels along the medial border of the psoas muscle. Common femoral artery injuries are commonly reconstructed using reversed saphenous vein, although e-PTFE or Dacron can be used if there is too great of a size mismatch. Placement of a prosthetic graft is acceptable if there is minimal to no contamination and there is adequate coverage. At a Role 2 facility, placing a shunt prior to transfer to a higher level of care is preferable to reconstruction with a prosthetic graft. Every attempt should be made to maintain flow into the profunda femoris artery, although the feasibility of this will depend upon the pattern of injury and the comfort level of the surgeon to perform a more complicated reconstruction. Coverage of vascular reconstruction in the groin is challenging; it may consist of local viable tissue, the sartorius muscle, or other options such as a rectus abdominis transfer flap. Coverage may be better addressed in a Role 3-4 facility. 1,3
Exposure of the proximal profunda femoris artery is obtained through a longitudinal incision used to expose the common femoral artery. Mid and distal segments are exposed through a vertical incision made parallel to the lateral border of the Sartorius muscle on the upper thigh, lateral to the proximal sartorius muscle. The sartorius is retracted medially and the rectus femoris is retracted laterally to expose the mid- and distal segments. Ligation of the circumflex profunda veins as they cross the artery is necessary. Often there are several of these crossing veins. Proximal profunda injuries should be repaired with reverse saphenous vein interposition graft. This is especially important if there is a question about the integrity of the superficial femoral or popliteal vessels. In this setting, flow through the profunda is most important to allow healing of subsequent lower extremity amputations. If patency of the superficial femoral artery can be confirmed, ligation of mid and distal profunda femoris injuries is acceptable as they lie deep in the thigh musculature and are not required for leg viability.3
Exposure is performed through a medial thigh incision and the adductors of the leg (i.e., adductor magnus). Exposure is facilitated by placing a lift or “bump” below the knee which allows the femoral artery, sartorius and adductors to be suspended, improving separation. Entry into the fascia of the lower thigh (distal superficial femoral artery) should be performed at the upper anterior margin of the sartorius which should be reflected down or posteriorly. Exposure is facilitated with the surgeon seated looking across to the dissection field with lights positioned directly over the surgeon’s shoulder if a headlight is not available.
When exposing the superficial femoral artery, it is important to recognize the femoral vein which is in proximity, if not adherent, to the artery. At the distal extent of the artery as it exits the adductor (Hunter’s) canal, there are large geniculate side branches which should be preserved or at least not injured as it causes hemorrhage. Repair of superficial femoral artery injury is best performed by reversed saphenous vein interposition graft from the uninjured leg.3
Vascular injuries in the popliteal space are exposed through a medial incision with the surgeon seated and lights over his or her shoulder. The dissection is extended from above to below the knee and is facilitated by a lift or “bump” under the calf of the leg with the knee flexed. When exposing below the knee, this bump is placed under the thigh. Natural dissection planes exist in exposing the above knee popliteal artery (i.e. popliteal space) except for the need to divide the fibers of the adductor magnus which envelop the distal superficial femoral artery (Hunter’s canal). Similarly, a natural dissection plane exists into the popliteal space from below the knee but added exposure should be accomplished by division of the gastrocnemius and soleus muscle fibers from the medial tibial condyle to allow a lengthy exposure of the below knee popliteal artery to the takeoff of the anterior tibial artery and the tibial-peroneal trunk. To completely expose the popliteal space, the medial attachments of the sartorius, semitendinosis, semimembrinosis and gracilis to the medial condyle of the tibia can be divided. When feasible, the pes anserinus should be reconstructed given its significant role in medial knee stabilization. Weitlaner, cerebellar retractors, flexible Adson-Beckman or Henly popliteal retractors with detachable side blades are necessary to expose the popliteal space. Typically, the medial head of the gastrocnemius can be retracted down using one of these devices and does not need to be divided.3
Many extremity venous injuries, especially small, distal veins, can be ligated with no adverse effects because of collateral venous drainage. However, ligation of more proximal or watershed veins, or even axial veins when collaterals have been destroyed by soft tissue wounds, will result in venous hypertension and congestion. In such instances an attempt should be made to repair the vein and restore venous outflow. Temporary shunts have been shown to be effective in restoring venous outflow in the femoral veins until formal repair can be accomplished. Techniques of lateral venorrhaphy are acceptable, although an interposition graft using saphenous vein from the uninjured limb is often necessary.
The patency of vein repairs in the lower extremity is 80% at 24 months with no increased incidence of pulmonary emboli compared to ligation. Additionally, a limb salvage benefit of vein repair compared to ligation has been shown 2 years after injury.5,6 Despite these advantages, repair of extremity venous injury should only be considered in instances when the patient’s overall status is able to tolerate additional procedures; otherwise, venous ligation is preferred, despite the increase in morbidity.
Technical considerations include removing thrombus from the distal venous segments with compression (e.g., ace wrap or Esmark bandage) prior to repair. Additionally, following venous repair, placement of a pneumatic compression device distal on the extremity will augment venous flow and improve patency. Lastly, if there is no contraindication, a prophylactic dose of low-molecular weight heparin (LMWH) should be initiated or low-rate heparin drip when LMWH is contraindicated.5
ALGORITHM FOR EXTREMITY VASCULAR INJURY
References