Subclavian Artery Injuries

The relatively short extent of the subclavian vessels, along with their surrounding and protective bony structures and musculature, makes injuries to these proximal upper extremity vessels rare. While injury to the subclavian arteries is more common in penetrating trauma, reports from military and civilian descriptions of vascular trauma show the prevalence of subclavian artery injuries to range from 1% to 10%.

Subclavian vascular injury should be considered when the bony structures of the thoracic outlet, such as the first rib or the clavicle are fractured. Subclavian artery injury may not present with critical ischemia given the robust collateral circulation around the shoulder. Absence of a distal pulse in an upper extremity, reduction in the injured extremity index (<0.9), or the presence of hemodynamic collapse with apparent mechanism should be considered highly suspicious for occult subclavian artery injury. In fact, many patients with a subclavian artery injury will present in shock. Hemopneumothorax is common. Other physical signs can include significant supraclavicular and low cervical swelling or tracheal compression from an expanding hematoma. Steps to gain immediate control include direct manual pressure to the supraclavicular area or Foley catheter tamponade. Concomitant injuries to the cervical or thoracic spine may be present, and brachial plexus injuries along with associated venous injury will commonly be present. Meticulous assessment for these injuries should be performed as soon as the patient’s status permits.

Axillary Artery Injuries

Axillary artery injuries are more common than subclavian artery injuries because they lack the protection of the structures of the thoracic outlet. Similar to subclavian trauma, penetrating trauma is the most common mechanism of axillary artery injury. However, in contrast to isolated subclavian artery injuries—in which the patient will present in shock—isolated injuries to the axillary artery rarely present with hemodynamic collapse. More common hallmarks include absent distal pulse or reduced injured extremity index (<0.9), pulsatile bleeding, and/or an expanding hematoma. The rich collateral network may preclude the development of critical ischemia, and an axillary artery injury may not be readily recognized without the aid of the continuous-wave Doppler and measurement of the injured extremity index. As with other forms of vascular trauma, arteriography is a useful diagnostic tool in certain situations including those in which an endovascular therapy is being considered. However, with good physical examination, continuous-wave Doppler use, and other noninvasive imaging modalities, most axillary artery injuries can be diagnosed without arteriography. Anterior dislocation of the humeral head or fractures of the humerus can result in axillary artery injury, and concomitant injuries to the nearby nerves of the brachial plexus and axillary vein are common.

Brachial Artery Injuries

Patients with brachial artery injury, especially those with injuries sustained from a penetrating mechanism, will typically present with hard signs of vascular injury. In some instances, however, critical ischemia may not develop due to the robust collateral network around the elbow. The degree of ischemia resulting from a brachial artery injured will depend on the following two factors:

• 1.
  

  Whether or not the injury occurred proximal or distal to the origin of the deep brachial artery

  
  
• 2.
  

  The degree of muscle and soft-tissue injury associated with the trauma. This second factor relates to injury or interruption of the deep brachial artery network and makes significant ischemia more likely in cases of penetrating injury with larger soft-tissue defects.

Radial and Ulnar Artery Injuries

Forearm artery injury is commonly reported in extremity vascular trauma series. The most common mechanism, as with the more proximal arteries of the upper extremity, is penetrating trauma. Hypothenar eminence hammer syndrome is a rare manifestation of repeated blunt trauma to the hypothenar eminence and distal ulnar artery. This can result in aneurysmal dilation, thrombosis, or distal embolization. Hematoma formation can result in development of compartment syndrome of the forearm and ultimately in a Volkmann flexure contracture. Signs of a tense hematoma with sensation, motor, or perfusion abnormalities should prompt consideration of a forearm fasciotomy.

Scapulothoracic Dissociation

This is a blunt injury of the upper extremity and shoulder girdle, resulting in complete musculoskeletal separation of the shoulder attachments from the torso with stretch and avulsion injuries to the brachial plexus and vasculature. Physical signs on presentation demonstrate chest wall hematoma, absent pulses, and loss of continuous-wave Doppler signals, along with complete upper extremity motor and sensory loss below the shoulder. X-ray imaging can show a laterally displaced scapula, distracted clavicle fracture, sternoclavicular disruption, or acromioclavicular disruption. This injury is rare; and one of the larger series, which reported 52 cases, showed that poor outcome is mostly related to neurologic injury, suggesting that there are no benefits to revascularization. Arterial ligation should be considered as a damage control option in a patient who is actively bleeding. When associated nerve transection and arterial injury are confirmed in the setting of musculoskeletal disruption, early amputation is generally recommended. This should be undertaken with consideration of the level of soft-tissue viability and the prospects for reconstruction, with a staged approach often being useful. Even in cases of successful limb salvage, scapulothoracic dissociation has been shown to result in significant short-term and long-term disability compared to isolated brachial plexus injury.

General Considerations in Addressing Complex Upper Extremity Vascular Trauma

Orthopedic and soft-tissue injuries often occur in tandem with upper extremity vascular injuries. This is especially germane in current combat given the increased use of high-energy improvised explosive devices. When faced with arterial injury in conjunction with bone and/or nerve injuries, several broad concepts should be reviewed. Orthopedic long bong injuries should be brought to length with either permanent or temporary fixation before definitive vascular repair. In most instances, when vascular and orthopedic injuries occur together, wound concerns require external fixation of the fracture with permanent internal fixation kept as an option, if needed, once other aspects of injury are optimized. Temporary vascular shunts should be considered to expeditiously restore perfusion to the distal extremity before placement of external fixation devices in these situations. This proven strategy or sequence allows for expedited perfusion to the extremity, a more thoughtful and well-done fixation, and an easier platform for definitive arterial and/or venous reconstruction.

Débridement of all clearly devitalized tissue should be performed when extensive, primary amputation needs to be considered. In our experience, routing of vascular bypass grafts through deep anatomic planes is possible in the great majority of injuries in which limb salvage is pursued. In the cases where large, cavitary soft-tissue defects are present, extraanatomic routes are needed and deep intermuscular or subcutaneous planes can be utilized depending on which path provides the best graft course and protection. Consideration must be given to primary repair of concomitant nerve injuries verses tagging the nerve ends for delayed neurorrhaphy once the wound has been stabilized. As described further in the following sections, repair of venous injury may improve limb outcomes and should be entertained particularly in axillosubclavian injuries and when other life-threatening injuries do not require attention. We give serious consideration to reconstruction of at least one vein in the upper arm when brachial, cephalic, and basilic vein disruption coexists ( Fig. 14-1 ). The brachial or basilic veins are favored for reconstruction because these lie within the exposures required to deal with colocated arterial injury and are more easily covered with soft tissue.

View from the patient’s head. A high-energy gunshot injury to the left inner arm resulted in a “blowout” injury at the bullet exit site. A greater saphenous vein (GSV) brachial artery to radial artery bypass was performed to address the brachial artery injury, and a GSV interposition graft was used to repair the basilic vein injury. Fasciotomy was performed. Arrows indicate cavitation injury, brachioradial GSV bypass, basilic vein interposition, and median nerve. A, Cavitation injury. B, Brachioradial GSV bypass. C, Basilic vein. D, Median nerve.

Approach to Tourniquets in Upper Extremity Trauma

Use of tourniquets in the modern civilian trauma setting has not been systematically endorsed, but the effectiveness of tourniquets has been demonstrated in the combat environment. Early application of tourniquets in Operation Iraqi Freedom (OIF)/Operation Enduring Freedom (OEF) has proven effective and life-saving in patients with extremity injuries. In 2009, Kragh et al reported that application of a tourniquet in the absence of shock in a prehospital setting had a significant survival advantage as compared to application of the tourniquet in the emergency department (ED) after the patient had developed shock (90% vs. 10%; p < 0.001). A small percentage (1.7%) experienced nerve palsy at the level of application, but no amputations resulted from tourniquet use.

In another study by the Israeli Defense Forces, the use of combat tourniquets was evaluated over 4 years. In all, 110 tourniquets were applied to for extremity injury, of which 34 were used to treat upper limb trauma. In that study, 94% of upper limb injuries were controlled by tourniquet, as compared to only 74% of lower extremity injuries. Neurologic complications developed in, seven limbs and four of these involved nerve palsies of the upper extremity.

Injuries distal to the axillary artery are most amenable to control by tourniquet. Designs include windlass tourniquets, such as the Combat Application Tourniquet (CAT) and the Special Operations Forces Tactical Tourniquet (SOFTT), which are commonly issued to combat troops, and pneumatic compression designs such as the Emergency and Military Tourniquet (EMT). One study of volunteers who self-applied the CAT, SOFTT, or EMT found each design to consistently interrupt distal perfusion as assessed by Doppler.

While there has been a historical apprehension for the use of tourniquets in the prehospital setting, these and other recent studies from the combat arena have shown tourniquets to be important means of preventing hemorrhage and saving lives. It is difficult to generalize this data to settings outside of military combat trauma systems which, through extensive training and rapid medical transport, have created the circumstances and successful outcomes observed with tourniquet application. Thus, while widespread recommendation for civilian prehospital tourniquet use may be somewhat premature, selected upper extremity injuries may be prudently treated by tourniquet assuming that the goal of early removal is achieved.

Considerations for success are as follows:

• 1.
  

  Tourniquets for hemorrhage control, temporary shunts for early restoration of perfusion, and low threshold for fasciotomy are important adjuncts to consider when facing delayed or complex upper extremity vascular injury.

  
  
• 2.
  

  Prepare and drape the patient to allow for appropriate proximal and distal control of the injury, as well as harvesting of autologous conduit such as saphenous vein.

  
  
• 3.
  

  Exposure in the upper extremity junctional zone is difficult. Be prepared for sternotomy and thoracotomy.

  
  
• 4.
  

  Long bong fractures should be brought to length before definitive vascular repair. (Consider immediate temporary vascular shunt placement followed by placement of fixation devices.)

  
  
• 5.
  

  Liberal use of interposition grafting and patching avoids the arterial narrowing that often results from primary repair.

  
  
• 6.
  

  Prosthetic conduit is an acceptable option in upper extremity junctional zone injuries where size match is important and where infectious complications are less common than in the groin.

  
  
• 7.
  

  Repair of venous injury may improve limb outcomes and should be entertained, particularly in the upper extremity junctional zone.

  
  
• 8.
  

  Endovascular repair of upper extremity vascular injury is now commonplace with reasonably early results, particularly in central junctional zone injuries.

  
  
• 9.
  

  Liberal use of duplex ultrasound as a surveillance mechanism for vascular repair is recommended.

  
  
• 10.
  

  Elevation of the extremity, early and aggressive rehabilitation, and antithrombotic therapy are important in the postoperative care after revascularization for upper extremity trauma.

Temporary Vascular Shunts in Upper Extremity Vascular Injury

Temporary intravascular shunts can allow for rapid restoration of distal limb perfusion when immediate vascular reconstruction is not possible ( Fig. 14-2 ). This may be due to delays involving orthopedic fixation, wound débridement and definition, vein harvest, lack of clinical expertise at the initial treating facility, or the need to address more life-threatening injuries. A full discussion on the use of vascular shunts follows in Chapter 17 . The use of intravascular shunting has been specifically applied within the military setting as a method to stabilize and temporize peripheral vascular injuries, to avoid vascular reconstructions in austere and forward environments with limited resources and time, and to allow for restitution and preservation of extremity perfusion during transport to definitive care. Further, shunting has been used during mass casualty events and during damage control in those with significantly adverse physiology or concomitant injuries. As such, robust and systematic evaluations of use have been performed during OIF and OEF.

Brachial artery temporary vascular shunt used to maintain distal perfusion while orthopedic fixation was performed to bring the humerus to length.

Chambers et al reported the use of 27 temporary vascular shunts in a U.S. Marine Forward Resuscitative Surgical System (FRSS) during OIF. Six (22%) of the shunts clotted during transport, but this did not impact early limb outcome. Only three of the shunts reported in this series were placed in upper extremity vascular injury (one brachial artery, one brachial vein, one ulnar artery), and none were reported to have resulted in early amputation. The one complication reported from upper extremity shunting involved a single shunt placed in the brachial artery, which clotted due to arm angulation and shunt kinking during transport. Another Navy FRSS report from OIF illustrated similar results with 96% shunt patency and 100% early limb salvage. Mean time to arrival at definitive Level III care was 5 hours 48 minutes (ranging from 3 hours 40 minutes to 10 hours 49 minutes), indicating the relative importance of reperfusion abilities forward. Rasmussen and colleagues chronicled descriptive data from the Balad Vascular Registry, a major Level III facility in Iraq, demonstrating shunts placed for proximal vascular injuries (at or proximal to the knee or elbow) had a significantly greater patency (86%, n = 22) than shunts placed in distal vascular injuries (distal to the knee or elbow) (12%, n = 8). However, no difference in early limb viability was identified between the groups (95% and 88%, respectively; p = NS), and thus failure of the distal shunts did not result in decreased limb viability.

In 2009, Gifford et al presented a longer-term outcome analysis in a case-controlled fashion with a time-to-event analysis portraying the impact of temporary vascular shunting on freedom from amputation, using data collected from the Joint Theater Trauma Registry (JTTR), including the Balad Vascular Registry (BVR) and the Walter Reed Vascular Registry (WRVR) from 2003 to 2007. Cases and controls consisting of 64 and 61 extremity arterial injuries, respectively, had a mean follow-up of 22 months. While the shunted group showed significantly higher mean injury severity scores when compared to the control group (18 versus 15, p = 0.05) after propensity score adjustment, use of TVS suggested a reduced risk of amputation but was not statistically significant (RR = 0.47; 95% CI [0.18 to 1.19]; p = 0.11). Interestingly, venous repair was associated with limb salvage (RR = 0.2; 95% CI [0.04 to 0.99], P = 0.05), whereas elevated mangled extremity severity scores ([MESS 8 to 12]; RR 16.4; 95% CI [3.79 to 70.79], P < 0.001) and fracture (RR = 5.0; 95% CI [1.45 to 17.28], P = 0.01) predicted amputation. Similar freedom from amputation was identified in both shunted and nonshunted extremities after definitive reconstruction (78% versus 77%; p = –0.5), but relative, graduated improvement in limb salvage with shunting was identified as the severity of the extremity injury increased.

While the above studies support the use of shunting for extremity injury in a combat setting, several case series describing use of shunts in the civilian setting have also been accomplished. These series report similar results and considerations regarding the use of shunts. Controversies regarding the use and theoretic benefit of venous shunts and therapeutic (or pharmacologic) shunting remain to be further studied and defined, along with the proper posture of shunting during transport in civilian settings.

Collectively, these experiences have defined the feasibility and usefulness of temporary shunting in the upper extremities, particularly with injuries to the brachial artery and more proximally. Certainly, there appears to be no harm in early reperfusion using shunts. The potential drawbacks—unrecognized vessel injury by shunts or the necessity for more extensive repairs owing to shunts and securing mechanisms—seem negligible overall. Even when faced with primary upper extremity vascular injury at the time of definitive management, the authors find that initial shunt use can be quite effective in providing time for operative planning and autologous vein harvest. Arterial injury identification, thrombectomy, regional heparin, and temporary shunt placement provide reperfusion while orthopedic lengthening and fixation is secured and/or autogenous vein harvest occurs. This simple strategy allows for earlier flow restoration, allows time for better definition of the vascular injury, and may create a more precise final revascularization with improved neuromuscular outcome.

Application of Mangled Extremity Scores in Upper Extremity Vascular Trauma

A mangled extremity is defined as a complex injury involving soft tissue, bone, nerve, and vasculature. Determining which patients and mangled upper extremities will benefit from aggressive attempts at limb salvage and which would be better served with primary amputation in the early stages of management can be challenging. Exhaustive efforts at limb salvage in severely injured patients may result in misdirection of care, whereas premature extremity amputation may preclude optimal functional outcome.

Scoring systems have been developed to take into consideration concomitant injuries, as well as the degree and nature of the bony, soft tissue; the nerve features, and the vessel features of extremity injury. These systems are designed to assist the surgeon in decision making during the early phases of mangled limb management and also to provide a mechanism to do a comparative retrospective study of extremity injury. These systems could theoretically discern between those extremities in which aggressive salvage would be successful and those in which up-front amputation would be most rational. Application of different scoring systems, such as the Mangled Extremity Severity Score (MESS) ( Table 14-2 ), Mangled Extremity Syndrome Index (MESI) ( Table 14-3 ), Predictive Salvage Index (PSI), and Limb Salvage Index (LSI), have been evaluated regarding their abilities to predict limb-salvage and long-term functional outcome. Only the MESI was proposed to evaluate mangled upper extremities, but the MESS has also been retrospectively applied to upper extremity injuries.

Table 14-2

Mangled Extremity Severity Score (MESS)

Adapted from Johansen et al: Objective criteria accurately predict amputation following lower extremity trauma.”

Variable	Injury Assessment	Points
Skeletal	Low energy (stab; simple fracture; civilian GSW)	1
	Medium energy (open or multiple fractures, dislocation)	2
	High energy (close-range shotgun or military GSW; crush injury)	3
	Very high energy (above + gross contamination; soft-tissue avulsion)	4
Limb ischemia	Pulse reduced or absent but perfusion intact	1 *
	Pulseless; paresthesias; diminished capillary refill	2 *
	Cool; paralyzed; insensate; numb	3 *
Shock	SBP always >90 mm Hg	0
	Transient hypotension	1
	Persistent hypotension	2
Age (years)	<30	0
	30-50	1
	>50	2

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Damage Control and Immediate Resuscitation for Vascular Trauma
2. Neck and Thoracic Outlet
3. Damage Control: Considerations for Vascular Conduit in the Repair of Vascular Injury
4. Asia: Sri Lanka

Stay updated, free articles. Join our Telegram channel

Join