Chapter 2 Operative Exposure of Vascular Injuries to the Upper Extremity

This chapter will discuss techniques for exposure of actual or suspected injuries of the vasculature of the upper extremity. Though the major emphasis of this lab experience is operative exposure, the topics of preoperative considerations, positioning, and management of specific injuries will also be briefly discussed.

Learning Objectives

By the end of the ASSET course, participants should be able to do the following:

1. Demonstrate incisions to expose axillary, brachial, radial, and ulnar arteries.
2. Demonstrate the steps to achieve surgical exposure of axillary artery and vein.
3. Demonstrate knowledge of the anatomic relationship between the musculoskeletal structures of the arm and the brachial artery.
4. Demonstrate knowledge of the anatomic relationship between the brachial artery and median nerve.
5. Demonstrate surgical exposure of radial and ulnar arteries below the elbow and above the wrist.

General Considerations

• Blind clamping of vascular injuries in the emergency department often produces unnecessary nerve and vessel damage.
• Bulky, reinforced dressings rarely provide adequate hemostasis and are usually best replaced by direct manual pressure (or tourniquet).
• The injured arm should be extended on an arm board. The entire extremity should be prepped into the field, including the back of the arm and the fingers. Prepping the groin and thighs allows for saphenous vein harvest for interposition grafting.
• In the upper extremity, a separate proximal incision is not always necessary to gain proximal arterial control.
• During the initial dissection, bleeding generally can be controlled by direct pressure or tourniquet application proximal to the injury.
• If desired, a sterile tourniquet may be placed above the injury. Inflate it only as needed, for a few minutes, if bleeding is troublesome during exposure. If used, a tourniquet should be deflated promptly when vessels are controlled and should not be used for vascular control.
• It is useful to imagine one continuous line for exposure of vascular injuries to the upper extremity (Figure 1).
  • This line begins on the superior edge of the sternal notch, runs laterally on the superior aspect of the clavicle, crosses mid-clavicle to the inferior clavicular border, traces the deltopectoral groove and then the bicipital groove, crosses the elbow obliquely, and runs on the radial side of the volar forearm to the wrist crease.
  • Any vascular injury on the upper extremity can be exposed by making an incision on this line, extending at least six centimeters proximal and distal to the suspected location of vascular injury. The exception is the ulnar artery which is exposed by making a second longitudinal incision along the ulnar side of the volar forearm. (Figure 1).

Axillary Artery and Vein

Anatomy

• The subclavian artery becomes the axillary artery as it crosses the first rib.
• The axillary artery runs under the pectoralis major and minor muscles, becoming the brachial artery as it crosses the lower border of the teres major muscle.
• The pectoralis minor muscle divides the axillary artery into three sections (Figure 2).
• A single axillary vein typically runs with the artery and is usually found inferior and superficial to it.
• The brachial plexus is intimately associated with the axillary artery, and care must be taken to avoid nerve injury during rapid exposure.
• The configuration of the brachial plexus at this level is highly variable and can range from a single large trunk running parallel to the artery to two or three branches that intermittently cross over or under the artery. This can make it challenging to determine the structures, especially in the setting of a hematoma or lack of pulsation in the artery.

Exposure

• The incision typically begins at the inferior edge of the center of the clavicle and runs laterally in the groove between the deltoid and the pectoralis major, which is exposed after incision through the skin and subcutaneous tissues (Figures 3 and 4).
• The pectoralis muscles lie on top of the axillary vessels. When there is no shock or active bleeding, the pectoralis major muscle can often be retracted medially or split in the direction of its fibers (Figure 5), allowing quick functional recovery. However, if there is bleeding or concern about adequate exposure, the pectoralis major tendon can be divided two centimeters from its humeral insertion.
• After splitting or dividing the pectoralis major, the pectoralis minor is divided, providing the first view of the second portion of the axillary artery (Figure 6).

• A single axillary vein typically runs with and caudal to the artery. The brachial plexus is intimately associated with the axillary artery and can be confused for the artery when a pulse is absent. Care must be taken to avoid nerve injury during rapid exposure. These anatomical relationships are shown in Figures 7 and 8.

Pitfalls

• Slow, incomplete, or piecemeal division of pectoral muscles delays hemorrhage control. This problem can be avoided by inserting a finger, clamp, or retractor under the entire muscle/tendon and dividing it quickly and completely.
• An inadequate incision makes exposure and hemostasis difficult. More distally, the vessels are superficial and exploration is typically quicker, with little risk of exsanguination during exploration. In the axilla, however, a generous incision is warranted to ensure quick vascular control.

Brachial Artery

Anatomy

• The brachial artery has a collateral system with one or more branches in the upper third of the arm (Figure 9) and is in close proximity to the median nerve (Figure 10).

• This collateral system may provide adequate perfusion to the hand even in instances of brachial artery transection or occlusion. Thus, the brachial artery can be ligated if necessary in select patients.
• In such cases, perfusion must be carefully monitored, with a low threshold for fasciotomy.
• The brachial artery is subcutaneous throughout its course in the upper arm, running in the groove between the biceps and triceps muscles in the medial arm (Figure 11).
• The radial, ulnar, and brachial arteries are each accompanied by two venae comitantes, usually one on each side of the artery. Multiple connecting branches from these veins form a web over the arteries; these veins may need to be ligated and divided to isolate the artery.
• In the mid-arm, the brachial venae comitantes are joined by the basilic vein as it penetrates the deep fascia and continues as the axillary vein. The cephalic vein courses superficially over the biceps muscle and enters the axillary vein in the deltopectoral groove.
• Proximally, the brachial artery lies between the median nerve anteriorly and the ulnar nerve posteriorly. Halfway down the upper arm, the median nerve crosses the artery and runs along the inferior-medial (ulnar) side of the artery.

Exposure

• The biceps and triceps muscle bellies are usually palpable on the medial aspect of the arm, and a generous incision is made in the groove between them (Figure 11). The neurovascular bundle is generally encased in fat, and “following the fat” between the muscle bellies aids in exposure.
• If needed, the incision is extended obliquely across the antecubital crease in a lateral direction, exposing the brachial artery bifurcation, the proximal radial artery, and the proximal ulnar artery (Figure 12).
• Between the antecubital crease and the arterial bifurcation, there is a dense, fibrous extension of the bicipital tendon (the bicipital aponeurosis) that can be divided along with the tendon to expose the bifurcation (Figures 13 and 14).
• Other than bicipital aponeurosis and tendon, the brachial neurovascular bundle is covered only by skin and subcutaneous tissue.
• In the mid-upper arm, the median nerve may be injured by careless dissection, as it runs directly on the artery. Knowledge of the anatomic relationships of the median nerve to the artery and its closely adherent paired veins is important to prevent iatrogenic injury (Figures 15 and 16).
• Sometimes, an injured brachial or basilic vein can be resected and used as an arterial conduit. If this procedure is planned, care should be taken not to harm the vein further during dissection or harvest.
• The brachial artery of a young, healthy patient can be surprisingly small when in spasm.
• If there is question as to whether the true brachial artery has been found, it should be followed proximally for confirmation.

Pitfalls

• In a pulseless extremity, a common mistake is to confuse the medial antebrachial cutaneous nerve (Figure 15) as the median nerve. The median nerve is quite large and is generally found inferior and superficial to the brachial artery and its paired vena comitans (Figure 16).

• If the dissection is carried below the biceps/ triceps groove, the ulnar nerve will be found and can be mistaken for the median nerve.
• Likewise, if the dissection is above the biceps/ triceps groove, the radial nerve will be found and can be mistaken for the median nerve.
• The level at which the brachial artery bifurcates is highly variable, ranging from well above the elbow to the mid-forearm. A generous incision (with extension as needed) will help avoid confusion of the anatomy.

Radial and Ulnar Arteries

Anatomy

• The brachial artery bifurcates into the radial and ulnar arteries just distal to the antecubital fossa, with the radial artery continuing in the same direction as the brachial artery, and the ulnar artery appearing to be a branch (Figures 17 and 18).
• As discussed above, the level at which the brachial artery bifurcates is highly variable and a generous incision (with extension as needed) will assist in sorting out anatomical variations.
• The ulnar artery is most commonly the dominant vessel to the hand. Careful evaluation of the hand and digital perfusion is required to determine the need for vascular repair versus ligation.
• The radial artery is covered by the brachioradialis muscle in the proximal forearm but is superficial in the distal forearm. At the wrist crease, the radial artery dives laterally under the thumb abductor and extensor tendon group.
• Two venae comitantes follow the radial artery throughout its course and may need to be ligated for complete arterial exposure.
• After arising from the brachial artery, the ulnar artery travels medially and parallel to the ulnar nerve. They are closely apposed for the remainder of the ulnar artery’s course in the arm.
• In the upper forearm, the ulnar artery and nerve lie under the superficial and deep flexor muscles. These muscles arise from the medial epicondyle and cross the artery in a medial to lateral direction. Distally, the artery emerges from underneath these muscles. It is palpable and superficial in the distal forearm before crossing over the flexor retinaculum at the wrist and becoming the superficial palmar arch.

Exposure

• To expose the proximal radial artery, an incision is made on the radial side of the volar forearm along the inferior and medial border of the brachioradialis (Figure 19a).
• If more proximal exposure is needed, the incision will travel obliquely across the antecubital fossa, as described above (Figure 12).
• The brachioradialis muscle is retracted radially (Figure 19b) to expose the fat pad between the brachioradialis and muscles (Figure 20a).
• Further dissection of this fat pad will expose the proximal radial artery and nerve (Figure 20b).
• The proximal ulnar artery can be exposed, as seen above in Figures 17 and 18.
• The remainder of the ulnar artery is exposed via a separate incision beginning just anterior to the medial epicondyle and traveling straight down the ulnar side of the volar forearm to approximately one fingerbreadth from the ulnar limit of the forearm (the point where the ulnar artery is typically palpated) (Figure 21a).
• The fat pad between the flexor digitorum superficialis and flexor carpi ulnaris muscles will contain the neurovascular bundle (Figure 21b).
• Further dissection of the fat pad will expose the ulnar nerve and artery, with associated veins lying on top of the flexor digitorum profundus muscle (Figure 22).

Pitfalls

• The ulnar artery and nerve run closely together in the distal forearm. The nerve can be damaged by careless dissection.
• The ulnar artery in the mid forearm may be covered by significant muscle in muscular individuals. An injury to the ulnar artery may be missed if the artery is not fully exposed.
• Upper extremity fasciotomy should be considered with long ischemia times or in cases where the brachial artery is ligated (chapter 5).