Thoracic Vascular Trauma

Presentation and Evaluation

Any patient with significant blunt chest trauma or penetrating injury around the thoracic cavity is at risk for vascular injury. The patient may provide useful history, but often this information is provided by prehospital personnel. The mechanism of injury, time from injury, vital signs, and neurologic status at the scene, as well as any changes during transport, are critical. With blunt injury specifics, such as prolonged extrication, the location and degree of occupant compartment vehicle deformation, speed and direction of impact, or height of fall may provide useful information. With penetrating trauma, the specific details are typically vague and often unreliable.

Evaluation proceeds according to the Advanced Trauma Life Support (ATLS) guidelines, and potentially life-threatening conditions are immediately treated. As with any trauma patient, thorax trauma may necessitate intubation for airway control. While these patients require evaluation and imaging for potential neurologic, intraabdominal, or extremity trauma, the discussion herein will focus largely on the diagnosis and characterization of thoracic vascular injuries. Physical examination, which should be performed both rapidly and thoroughly, has been shown to be reliable and can often help make the diagnosis. The presence of distended neck veins, tracheal deviation, subcutaneous emphysema, chest wall ecchymosis and/or instability, absent breath sounds, or muffled heart sounds may all provide crucial information. Likewise, the absence of an upper extremity pulse suggests a proximal arterial injury. Vital signs should be frequently monitored with careful observation of the work of breathing and oxygen saturation. Overall, the most common thoracic injuries are hemothorax and/or pneumothorax. However, rapid diagnosis of vascular injury is paramount to success in most instances.

Penetrating thoracic trauma in a hemodynamically unstable patient warrants operative intervention. The decision regarding surgical exposure may be problematic, especially if there is concomitant abdominal injury. Clinical judgment is paramount in this situation. The hemodynamically stable patient may benefit from additional imaging, with CTA as the first-line modality, which provides more detailed and organ-specific information.

Indications for Emergent Operation

While the vast majority of traumatic thoracic injuries can be managed nonoperatively, surgery may be indicated emergently, urgently, or in a delayed fashion. Indications for emergent thoracic exploration include tracheobronchial perforation, endobronchial blood loss, cardiac tamponade, shock with a penetrating chest injury, initial chest tube output of 1500 cc, or persistent chest tube output of 200 cc/h for 2–4 hours. There is likely a linear relationship between the total amount of thoracic hemorrhage and mortality, necessitating a familiarity of the treating surgeon with the most common exposures that will be required in an emergent setting. The patient’s overall clinical condition and astute surgical judgment are of paramount importance when deciding to operate and what type of surgical exposure or approach to utilize.

Open Surgical Exposure/Incisions

There are several surgical approaches to the thorax, each with advantages and disadvantages for emergent trauma applications. The surgeon should be familiar will all of them, and the clinical situation should determine the choice of incision. Hemodynamically unstable patients may not tolerate lateral positioning, as it may exacerbate hypotension. In addition, in the emergent exploration of the unstable trauma patient, the only imaging is likely to be portable chest radiograph. In this scenario, the surgeon will have limited knowledge of potential mediastinal involvement, the projectile’s path, or additional cavitary involvement. With penetrating thoracic trauma, there is the possibility of injury to adjacent body regions, such as the abdomen and neck. Therefore, a thoracic incision must prove versatile in accommodating flexibility in the conduct of operation. In this setting, incision selection requires careful consideration of the appropriate extensions that can be made to best optimize exposure and control options.

In the stable patient, additional imaging data is more likely to have been obtained. Armed with better understanding of the location and nature of injury, a better decision regarding optimal therapy can be formulated. In the modern endovascular age, this information may facilitate the effective utilization of less-invasive adjuncts. However, knowledge of open surgical options and defaults remain paramount. If open exploration or repair is selected, the choice of incision should be guided by the CT findings.

Commonly employed open operative approaches include anterolateral thoracotomy, posterolateral thoracotomy, bilateral thoracotomy (or “clamshell thoracotomy”) and median sternotomy ( Fig. 181.4 ). The left anterolateral approach is perhaps the most expedient – and extending it across the midline affords excellent exposure to both pleural spaces, the anterior mediastinum and nearly the full complement of thoracic vascular structures. Likewise, the incision can be continued as a celiotomy for abdominal exploration and is preferred over the posterolateral approach in the patient in shock. The main disadvantage of the left anterolateral approach is exposure of posterior thoracic structures. By extending the ipsilateral arm and placing a bump to elevate the thorax approximately 20 degrees, the incision can be carried to the axilla – a maneuver that will improve posterior exposure. The posterolateral thoracotomy affords optimal exposure of the hemithorax, especially the posterior structures, and is the standard incision for most elective thorax operations. Its lack of versatility limits the usefulness in trauma, but is the preferred approach to repair any injury pattern that also involves intrathoracic tracheoesophageal injuries. Sternotomy provides excellent access to the heart, proximal great vessels, and anterior mediastinum. This particular incision is versatile, and can be extended as an abdominal, periclavicular, or neck incision. The “trap door” incision is rarely used, since left-sided thoracic vessels can be approached via sternotomy with extension.

Operative Techniques

Thoracic vascular injuries after significant trauma rarely occur in isolation, particularly after penetrating mechanisms. Therefore, it is useful to appreciate a few key nonvascular operative techniques that may be required during emergent operative exploration. Among patients requiring emergent thoracic exploration, between 20% and 30% will need a pulmonary resection, which ranges from wedge resections to major anatomic resections. ^, A large retrospective National Trauma Data Bank study analyzed 3107 adult patients who sustained severe chest trauma and required any type of lung resection found that wedge resection was performed in 54.3%, followed by lobectomy in 38.2% and pneumonectomy in 7.5%, with an overall morbidity and mortality of 32% and 27.5%, respectively. Pneumonorrhaphy, wedge resection, tractotomy, and formal anatomic resection are all techniques that can be utilized to manage pulmonary parenchymal injury. The trauma surgeon should be facile with all of these techniques, and the choice of a particular one is driven by the patient’s clinical condition and the extent and location of the pulmonary injury. The widespread adoption of a variety of surgical staplers has facilitated tractotomy and pulmonary resections. Pneumonorrhaphy is the simplest technique and is applicable to superficial pulmonary lacerations. These can be closed with an absorbable running simple or mattress suture. Injuries near the lung periphery can be excised by a stapled wedge resection. The lung is mobilized, any adhesions are lysed, and the inferior pulmonary ligament may need to be divided to improve lower lobe exposure. A stapled wedge resection is performed by grasping the parenchyma with a Duval or Foerster lung clamp and firing the stapler to excise the peripheral tissue. Tractotomy is rapid and ideal for through-and-through parenchymal injuries. Placing the jaws of the stapler through the tract and firing it will open the tissue. Bleeding vessels or air leaks can then be individually ligated. Tissue thickness will determine the appropriate size staples, and at times, the staple line needs to be oversewn with a running absorbable suture.

More centrally located injuries, especially those close to the hilum, require special consideration. Precise understanding of the pulmonary vasculature and hilar anatomy are necessary to safely perform a stapled resection for centrally located injuries. If a nonanatomic resection is precluded, as with extensively damaged lung parenchyma, a formal lobectomy is necessary. Hilar injuries present a significant challenge. Hemorrhagic shock is invariably present, and the injury necessitates pneumonectomy, which carries a prohibitive mortality. Several techniques can be used to obtain hilar control, including lung torsion, manual compression, and application of a vascular clamp. Manual compression followed by clamping is the most widely used. Very proximal hilar injures are particularly problematic, and opening the pericardium will occasionally allow vascular control.

Blunt Thoracic Aortic Injury

BTAI remains the second most frequent cause of mortality after blunt force trauma. ^, An autopsy study conducted by Teixeira and colleagues at Los Angeles County Hospital identified thoracic aortic injury (TAI) as a contributor in one third of automobile accident deaths. National Vital Statistics data suggest that the majority of deaths (80% to 85%) due to BTAI occur prior to the arrival to a hospital facility.

Among patients who survive to receive care, continued medical advances have improved the ability to expediently diagnose and effectively treat BTAI. Thoracic endovascular aortic repair (TEVAR) has replaced traditional open repair (OR) as the primary treatment modality utilized for BTAI among anatomically suitable patients. ^, Among patients with severe BTAI, the subsequent use of TEVAR has been associated with improved morbidity and mortality compared with traditional OR approaches. ^{, ,} Given these results, and following a 2011 analysis of the accumulated literature, the Clinical Practice Guidelines from the Society for Vascular Surgery (SVS) suggested that “endovascular repair be performed preferentially over open surgical repair or nonoperative management.”