Hemodynamically stable patients with penetrating wounds in proximity to the thoracic outlet should undergo surgeon- performed ultrasound and a chest x-ray. The ultrasound will rule out an associated cardiac injury and document the presence of a hemothorax or pneumothorax. The chest x-ray will aid in tracking the course of the missile and in documenting the presence of a hematoma in the superior mediastinum, base of the neck, or supraclavicular area. There have been several retrospective studies that have documented that a normal physical examination and chest x-ray virtually exclude a vascular injury at the thoracic outlet.17,18 Even so, certain trauma centers will use a screening CT as an added study to determine the track of a penetrating wound in this area.19 When the track of a missile or knife wound is in proximity to vessels at the thoracic outlet and there is an adjacent hematoma on the chest x-ray, digital subtraction arteriography (DSA) of the carotid, vertebral, and subclavian arteries or a CT arteriogram (CTA) is performed. This will document the presence and location of a vascular injury and allow for the choice of an appropriate operative incision.
Evaluation of patients with modest or moderate symptoms or signs or an asymptomatic patient.
There are symptoms (hoarseness, dysphagia, odynophagia), signs (palpable crepitus, continuing air leak through the wound), or findings on a cervical or chest x-ray (cervical or mediastinal air) that suggest a possible injury to the trachea or esophagus. The diagnostic workup is described in Section “Zone II.”
The approach to possible injuries in this zone has varied considerably over the past 55 years. Based on the report by Fogelman and Stewart20 at Parkland Memorial Hospital in 1956, mandatory exploration for wounds penetrating the platysma muscle was recommended. This recommendation was based on a mortality rate of 6% in patients undergoing early operation versus 35% in those undergoing delayed operation.
It quickly became obvious, however, that cervical explorations in all patients (overtly symptomatic, modestly or moderately symptomatic, asymptomatic) with penetration of the platysma muscle in Zone II resulted in a “negative” exploration rate of approximately 50%.21 A more selective approach to operation based on symptoms and signs as described above was then adopted by many centers. One review article in 1991 comparing the two approaches noted that mandatory cervical exploration for platysma penetration had a mortality rate of 5.8% versus 3.7% for a selective approach.22 Of interest, a negative or nontherapeutic cervical operation occurred in 46.2% of patients treated with mandatory exploration. When patients with modest or moderate symptoms or signs or those who are asymptomatic are managed with a selective approach, only 55–65% eventually come to operation. Numerous large studies subsequently verified the safety of a selective approach in the 1980s and 1990s.23–33
Physical examination alone is highly accurate in evaluating an asymptomatic patient with a penetrating (through the platysma muscle) stab wound in Zone II. This is true for patients with gunshot wounds in Zone II, as well, as long as the track is tangential or away from the vascular (lateral) or aerodigestive tract (central).33–35 With platysma penetration, but without further evaluation by CT, CT angiography, duplex ultrasonography, or endoscopy, serial examinations of the patient’s neck every 6–8 hours for 24–36 hours are appropriate.
CT has been used as an adjunct to physical examination over the past decade in selected centers.19,36,37 In asymptomatic patients with a normal physical examination after a penetrating wound in Zone II, it “contributes minimally” to the sensitivity of physical examination.37 When patients have no “hard signs” of vascular injury in Zone II, but are “at risk for injury to vital structures within the neck,” CT can demonstrate a trajectory away from these structures.19 With such a trajectomy, “invasive studies can often be eliminated from the diagnostic algorithm.”19 A more recent study using multislice helical computed tomography/angiography (MCTA) documented a “100% sensitivity and 95.5% specificity in detecting all vascular and aerodigestive injuries sustained.”38
Arteriography, Duplex Ultrasonography, Color Flow Doppler, Cta
Patients with “hard” signs of a vascular injury in Zone II present with external bleeding, bleeding into the trachea or esophagus, an expanding or stable large hematoma, and/or an audible bruit/palpable thrill. Patients with bleeding or an expanding or large stable hematoma undergo an emergency cervical exploration. A patient with a likely arteriovenous fistula should have some type of vascular diagnostic study performed. Should a fistula between the internal carotid artery and jugular vein be present, an endovascular stent rather than cervical exploration may be chosen.
In patients with “soft” signs (modest or moderate signs) of a vascular injury in Zone II such as a history of bleeding at the scene, proximity of a stab, missile, or pellet track, or a small nonexpanding hematoma, the role of arterial diagnostic studies remains controversial. As noted above, physical examination alone is highly accurate in ruling out an arterial injury in the asymptomatic patient. Much as in evaluating possible peripheral arterial injuries, however, there is at least a 3–5% chance of a surgically reparable arterial lesion in a patient who presents with a cervical vascular “soft sign.” And it is likely that a combination of “soft signs” (i.e., proximity of wound and small hematoma) will increase the need for surgical intervention. Therefore, some type of diagnostic study is performed in patients with “soft signs” in most centers (Fig. 22-7).
Pellet wound in an asymptomatic patient caused 30% transection of left common carotid artery in Zone II. Arteriogram performed secondary to traverse of missile through Zone II.
Four-vessel cerebral arteriography was the longtime standard of care for evaluating the carotid and vertebral arteries. The technique is highly accurate in diagnosing arterial injuries, eliminating nontherapeutic explorations, and allowing for transcatheter embolization when indicated.39,40 The disadvantages include the time required to allow the interventional radiology team to return to the hospital at night, the dye load required, and the low yield when all asymptomatic or modestly symptomatic patients are studied.41
Duplex ultrasonography, a combination of real-time brightness (B)–mode imaging and pulsed Doppler velocimetry, has been used in the diagnosis of atherosclerotic occlusive decrease of the carotid artery for 35 years.41–43 Basically, the technology produces images that define anatomy and a spectral profile that documents flow through the vessel. Numerous reports during the 1990s documented the ease and accuracy of the technique when applied to patients with penetrating wounds in Zone II.44–47 It was suggested that duplex replace conventional arteriography because of ease of performance and the significant cost-savings that would result.46–48 This did not happen over time in most trauma centers as the technique can be performed only by a registered vascular technologist or experienced vascular surgeon trained in duplex.
A related technique of “color flow Doppler” has been used to evaluate the carotid arteries after penetrating trauma to Zone II, as well.49,50 In this technique, flow to and from the point of the Doppler examination is represented on a color scale. Several studies in the 1990s documented that the combination of a careful physical examination and color flow Doppler was a safe alternative to routine contrast angiography.49,50
For the past 15 years there have been ongoing studies to determine the accuracy of CTA, particularly in patients with possible blunt cerebrovascular injuries (BCVI; to be discussed). Penetrating cervical injuries have been studied, as well, with early reports coming from the Hospital Universitario San Vicente de Paul in Medellin, Colombia.51,52 Based on the ease and speed of obtaining accurate images reconstructed at 1-mm intervals, the authors from this well-known trauma center concluded that “helical CT can replace conventional angiography in this setting” (penetrating injuries to the neck).52 Another early report from 2005, before the current generation of 32- and 64-slice detectors, documented that the use of CTA significantly decreased the number of conventional arteriograms required and negative cervical explorations performed.53 The enthusiasm for using CTA is tempered, of course, by continuing concerns about its accuracy in evaluating possible BCVI.54 But the aforementioned 2006 study with a 100% sensitivity in evaluating patients with penetrating cervical wounds is certainly reassuring.38 Based on available data, it appears that multidetector helical CTA is slowly replacing conventional arteriography as a rapid screening modality to evaluate possible arterial injuries in Zone II after penetrating trauma. An equivocal screening study or one in which the anatomic area of interest is obscured by artifacts created by adjacent metallic fragments should be followed by a conventional arteriogram.
Patients with modest or moderate symptoms of an esophageal injury present with complaints of deep cervical pain, dysphagia, odynophagia, or hematemesis. On examination, palpable crepitus and deep cervical tenderness may be present. An x-ray of the neck will usually demonstrate retropharyngeal or retroesophageal air in the soft tissues, while a pneumomediastinum will be present on a chest x-ray if there has been a delay in the patient’s arrival in the trauma center.
Historically, the time-honored “sip test” was performed in such patients in centers with limited resources.30 A patient who was able to swallow a mouthful of water without severe discomfort was felt to have only a small injury or no injury of the cervical esophagus and was admitted for observation only. The patient who had severe pain with swallowing would then undergo standard diagnostic testing to evaluate for the presence of an esophageal injury.
While CT has now been widely applied in the diagnostic evaluation of patients with penetrating and blunt cervical trauma as previously noted, its accuracy in detecting an injury of the cervical esophagus is unclear. This is because several of the reports in which CT has been evaluated do not include any patients with esophageal injuries.36,38 For this reason, asymptomatic patients with air in the soft tissues of the neck after trauma, those with a positive “sip” test, or those with a combination of modest/moderate symptoms and signs of an esophageal injury undergo the standard diagnostic evaluation using a contrast esophagogram and endoscopy.55–57
While there is a risk of secondary necrotizing pneumonitis and pulmonary edema if the contrast agent Gastrografin (meglumine sodium) is aspirated, it remains the initial contrast agent of choice for esophagograms in most centers.56 The accuracy of detecting an injury to the cervical esophagus with this agent is 57–80%.57–60 A “thin” barium study follows a negative Gastrografin swallow or has been used as the primary contrast agent in some centers.56,57
As contrast esophagograms with either Gastrografin or thin barium have a less than 100% sensitivity in diagnosis, flexible esophagoscopy is next performed in the at-risk patient with a negative contrast study. It has long been known that the combination of a contrast study and esophagoscopy has an accuracy of nearly 100% in patients with esophageal injuries in Zone II.61 In two studies describing the results of flexible esophagoscopy specifically over the past 16 years, sensitivity was 98.5–100%, specificity 96–100%, and accuracy 97–99.3%.62,63
Patients with modest or moderate symptoms of an injury to the larynx or cervical trachea present with hoarseness, stridor, or hemoptysis. On examination, contusions over the larynx or cervical trachea, palpable crepitus, deep cervical tenderness and bubbling, or an ongoing leak of air from a penetrating wound may be present. As with injuries of the cervical esophagus, paratracheal air or a pneumomediastinum will usually be present on cervical and chest x-rays.
In asymptomatic patients with air in the soft tissues of the neck or those with a combination of modest/moderate symptoms and signs of a tracheal injury, the traditional diagnostic evaluation includes laryngoscopy and fiber-optic tracheoscopy and bronchoscopy. Laryngoscopy will diagnose and localize an injury to the supraglottic, glottic, or subglottic larynx.6 A vertical fracture of the thyroid cartilage with rupture of the thyroepiglottic ligament is an example of a supraglottic injury and results in retraction of the epiglottis. A fracture of the thyroid cartilage with an associated rupture of the thyroarytenoid muscles extending into the true vocal cords and aryepiglottic folds is an example of a glottic injury and results in hoarseness or stridor. As previously described, a significant injury to the lower thyroid cartilage and cricoid cartilage with separation from the trachea would result in acute respiratory distress long before a laryngoscopy could be performed.64
Fiber-optic tracheoscopy and bronchoscopy is used to evaluate stable patients with suspected injuries to the trachea and major bronchi.65,66 The technique allows for placement of an endotracheal tube over the fiber-optic bronchoscope in patients with impending airway distress and for detection of penetrating or blunt perforations.
Of interest, the aforementioned study using multidetector CT (MCT) in penetrating wounds of the neck documented the presence of 6 tracheal injuries in the 12 patients with positive MCT studies.38 Larger studies will be necessary to confirm the diagnostic accuracy of MCT in detecting laryngeal and tracheal injuries.
Historically, conventional arteriography was recommended for all stable patients with penetrating wounds in Zone III.67 Much as with mandatory diagnostic studies and/or operation in all patients with penetrating wounds of the neck, the approach to wounds in Zone III is now more selective.68 As with the other zones of the neck, patients with hard signs of an arterial injury in Zone III have a greater than 90% chance of having a positive cervical exploration. Patients without hard signs, however, rarely have an arterial injury on conventional arteriography that will require surgical intervention.68–70 Of course, arteriography or CTA will be of value in a select number of stable patients with hard signs not including bleeding or a combination of soft signs such as a history of bleeding, proximity of wound, and/or a nonexpanding hematoma in this location. When a limited arterial injury is diagnosed on one of these studies, observation or endovascular therapy would be appropriate (to be discussed).