Gina M.S. Howell
Jason L. Sperry
Presentation
A 25-year-old female involved in a domestic dispute presents to the emergency department with a stab wound to the left neck. On admission, she is normotensive, protecting her airway, has no signs or symptoms of respiratory difficulty, and is neurologically intact. Focused neck examination reveals a single 2-cm wound anterior to the sternocleidomastoid (SCM) muscle at the level of the thyroid cartilage. There is a small, pulsatile hematoma with an associated bruit, and a moderate amount of crepitus on palpation. Plain films demonstrate subcutaneous emphysema, no tracheal deviation, and no pneumothorax.
Differential Diagnosis
Penetrating trauma in the cervical region can result in significant morbidity and mortality, as it is a relatively unprotected area with a high density of vital structures. Specific injury patterns depend upon the anatomic level of injury (Table 1). This patient has a Zone II injury placing her at risk for damage to the carotid and vertebral arteries, jugular veins, vagus nerve, larynx, trachea, esophagus, and spinal cord.
TABLE 1. Anatomic Zones of the Neck and Associated Injuries
Workup
The initial evaluation of every trauma patient should adhere to the principles of the Advanced Trauma Life Support–directed primary survey with rapid assessment of the airway as the ultimate priority. Translaryngeal endotracheal intubation by a skilled practitioner is the preferred method of airway control, but one must be prepared to provide an emergency surgical airway if necessary. The focused physical examination that follows should assess for signs and symptoms of significant vascular and aerodigestive tract injury (Table 2). “Hard” signs mandating immediate operative exploration without the need for additional diagnostic workup include shock/hypotension, active hemorrhage, expanding or pulsatile hematoma, bruit, loss of pulse, neurologic deficit, significant subcutaneous emphysema, respiratory distress, or air leaking through the neck wound. Plain chest and cervical radiographs are typically taken for all patients during this initial assessment primarily to evaluate for serious injuries (e.g., pneumothorax, hemothorax, tracheal deviation) requiring expeditious treatment.
TABLE 2. Clinical Signs and Symptoms of Significant Injury
aIndicates hard sign of injury mandating operative exploration.
In stable patients with wounds that penetrate the platysma but who do not need immediate exploration, further radiographic and endoscopic evaluation is usually recommended to evaluate for surgically significant injuries. Though practice patterns vary among institutions, computed tomography (CT) has become the backbone of modern trauma evaluation and is often used as the initial diagnostic study. The addition of intravenous contrast (computed tomographic angiography [CTA]) makes this modality even more useful for determination of injury track, proximity to vital structures, and is the preferred method over conventional arteriography and duplex ultrasonography for the detection of vascular injuries (Figure 1). As an adjunct to CT, it is also prudent to formally evaluate the esophagus with barium contrast esophagography (Figure 2) or esophagoscopy, with many centers utilizing both techniques on a routine basis. Suspicion of laryngotracheal injury warrants laryngoscopy and bronchoscopy.
FIGURE 1 • CTA of the neck. CTA is the initial diagnostic study of choice in the evaluation of penetrating neck wounds that do not require immediate exploration. This image demonstrates subcutaneous emphysema concerning for injury to the aerodigestive tract.
FIGURE 2 • Barium contrast esophagogram. Clinical exam alone is unreliable in excluding esophageal injury. Formal evaluation with barium esophagogram and/or esophagoscopy is recommended to minimize the consequences of missed injury or delay in diagnosis. This image demonstrates a normal study without evidence of contrast extravasation.
Diagnosis and Treatment
This patient has a penetrating wound in Zone II. She likely has a significant vascular injury based on the finding of a pulsatile hematoma and associated bruit. In addition, she may also have an injury to her aerodigestive tract as evidenced by subcutaneous emphysema on clinical and radiographic examination. She is not unstable and does not require emergent intubation, but does have “hard” signs of injury, and therefore, should go immediately to the operating room for exploration. Cervical immobilization is unnecessary due to the extremely low likelihood of unstable spine fracture in this setting, and can actually be harmful by interfering with serial neck examination and potential life-saving maneuvers.
Discussion
It is universally accepted that all patients with hemodynamic instability or hard signs of injury require emergent operation without the need for additional diagnostic workup. There is variability, however, in the management of patients who do not fall into this category. The era of mandatory exploration for every penetrating neck wound and its high associated nontherapeutic exploration rate has certainly passed, but may still serve as the most appropriate strategy in situations where immediate radiologic and endoscopic capabilities are not readily available. Selective operative management, on the other hand, relies upon serial observation and ancillary studies to effectively diagnose or rule out injuries requiring surgical intervention. There is a negligible rate of missed injury with this approach and is the strategy advocated by most, particularly for injuries that may involve Zones I and III because of the difficulty in examining and exposing these areas. Simple observation alone should be exercised with caution even in asymptomatic patients with no signs of significant injury, as some injuries (e.g., esophageal) are often clinically occult at the time of presentation. A suggested management algorithm for penetrating neck injuries is depicted in Figure 3.
FIGURE 3 • Suggested management algorithm for Zone II penetrating injuries. *Observation alone should be exercised with caution, as some njuries may be clinically occult at the time of presentation.
Surgical Approach
A standard Zone II neck exploration is performed under general anesthesia with the patient positioned supine on the operating room table with arms tucked, neck extended, and head rotated to the contralateral side (Table 3). A vertical neck incision along the anterior border of the SCM muscle is routinely utilized (Figure 4). Once the dissection is carried through skin, subcutaneous tissue, and platysma, posterolateral retraction of the SCM provides exposure to all vital structures. Unless there is another obvious injury requiring immediate attention, the vascular structures are typically explored first by opening the carotid sheath. Division of the middle thyroid and facial veins will facilitate complete visualization the carotid artery, which lies deep and medial to the internal jugular vein. Attention is then turned to the aerodigestive tract with care taken not to injure the recurrent laryngeal nerve, which lies in the tracheoesophageal groove. Mobilization of the esophagus is accomplished by dissecting in the posterior areolar plane and then encircling the esophagus with a Penrose drain to facilitate rotation and circumferential inspection. The larynx and trachea should be visualized and palpated for signs of injury. This may require mobilization of the thyroid and/or division of strap muscles. Intraoperative esophagoscopy and bronchoscopy are often utilized to supplement direct open examination and minimize the incidence of missed injuries.
TABLE 3. Key Technical Steps and Potential Pitfalls in Zone II Neck Exploration
FIGURE 4 • Incisions for exposure of penetrating neck injuries.
Management of Common Zone II Injuries
Vascular Injury
It is currently recommended that all common and internal carotid artery injuries should be repaired, even in patients presenting with significant neurologic deficits, as early revascularization has consistently been associated with improvement or stabilization of neurologic symptoms. Proximal and distal control of the common, external, and internal carotid arteries must be obtained before definitive repair. If exposure is less than ideal, vascular control can be accomplished with a Fogarty balloon catheter. Prior to clamping, consideration should be given to heparinization provided there are no contraindications. Shunting is usually unnecessary in the typical young trauma patient, but should be employed if there is suspicion for cerebral malperfusion or evidence of poor back bleeding.
Sharp penetrating weapons typically result in relatively clean injuries that are amenable to primary repair with minimal debridement. Arteriorrhaphy can be accomplished with interrupted 6-0 polypropylene sutures. If the laceration is circumferential, an end–end repair may be performed. If the injury is near the bifurcation of the common carotid into its internal and external branches, a patch angioplasty will help minimize the development of stenosis. Large perforations or defects are unlikely from this mechanism, but if present are treated with segmental resection and interposition graft. Saphenous vein conduit is preferred for this purpose due to superior long-term patency compared with polytetrafluoroethylene.
Whenever possible, internal jugular vein injuries should be repaired. However, if the patient is unstable or simple repair is not feasible this vessel can be ligated unilaterally with minimal morbidity. Similarly, the external carotid artery may be safely ligated secondary to extensive collateral circulation. Due to difficult access, bleeding from the vertebral vessels is best managed by temporary control of hemorrhage in the operating room, followed by immediate transfer to the arteriography suite for embolization.
Esophageal Injury
Expeditious diagnosis is critical in limiting the morbidity and mortality associated with esophageal injuries. If detected within the first 12 to 24 hours, the vast majority of full-thickness stab wound injuries can be repaired primarily in a two-layer fashion. The area should be widely drained and a local muscle flap should be placed to buttress the suture line, particularly if there is a concomitant tracheal or vascular injury. In the event of the latter, it is preferable to place drains via a contralateral neck incision to avoid the catastrophic consequences associated with blowout of a fresh carotid repair. Severely destructive injuries requiring esophageal exclusion with gastrostomy and jejunostomy are extremely rare. After any repair, a barium swallow should be performed between postoperative days 5 and 7 before initiating oral intake.
Tracheal Injury
Most penetrating tracheal injuries that occur as the result of stab wounds occur without significant tissue loss and can be repaired primarily. This can be accomplished in a single layer utilizing 3-0 absorbable sutures in an interrupted fashion. Again, interposition of wellvascularized tissue (omohyoid or SCM muscle) is essential to minimize risk of fistula formation. Concomitant tracheostomy is not routinely indicated to protect a tracheal repair. If performed, tracheostomy should be placed one ring distal to the injury and should be limited to severe crush injuries, major laryngeal injuries, tears that traverse >1/3 of the circumference, or when prolonged postoperative ventilatory support is anticipated. Early extubation is safe and recommended.
Special Intraoperative Considerations
It is not uncommon to find injuries that traverse more than one zone, requiring additional access incisions. Unfortunately, this is not always known beforehand in the patient who proceeds directly to the operating room without the benefit of preoperative diagnostic imaging. Zone I injuries may necessitate a median sternotomy, a supraclavicular incision with resection of the head of the clavicle, or a combined “trapdoor” approach involving the addition of an anterolateral thoracotomy. Zone III injuries are notoriously difficult to expose, requiring cephalad extension of a standard vertical Zone II incision with possible disarticulation or partial resection of the mandible and in some instances limited craniotomy. Commonly utilized surgical incisions are illustrated in Figure 4.
Postoperative Management
Patients will typically be monitored in the intensive care unit during the immediate postoperative period where frequent neurologic assessment and hemodynamic monitoring can be performed. Early postoperative complications related specifically to neck exploration can include hemorrhage, recurrent laryngeal nerve injury, and esophageal leak. Unilateral recurrent laryngeal nerve injury will produce hoarseness and require formal evaluation by an otolaryngologist with laryngoscopy. Postoperative hemorrhage can be rapidly fatal if not recognized promptly. The confined space of the neck can result in airway compromise if bleeding is not controlled. Fortunately, leak in the cervical esophagus typically results in localized abscess amenable to drainage, whereas leak involving the thoracoabdominal esophagus can result in fulminant mediastinitis, which is often fatal.
Case Conclusion
The patient undergoes standard central neck exploration. After evacuation of a moderate-sized hematoma, you find a clean-based laceration of her internal carotid artery and internal jugular vein, both of which are amenable to primary repair. You also find a small anterior tracheal tear, which is also repaired primarily. The esophagus is visualized externally and internally with ex ible endoscopy and there is no evidence of injury. The patient is extubated immediately after the operation and taken to the intensive care unit for monitoring. A barium swallow performed on post operative day 1 confirmed no evidence of esopha geal injury, and an oral diet is begun. The patient is discharged home on postoperative day 5.
TAKE HOME POINTS
· Assessment and management of the airway is the top priority.
· Hemodynamic instability or “hard” signs of injury require immediate surgical exploration.
· Both mandatory exploration and selective operative management can be equally justified in the appropriate clinical setting for Zone II injuries.
· Esophageal injuries are often clinically occult at presentation, and early diagnosis is important to minimize associated morbidity and mortality.
· All common and internal carotid injuries should be repaired.
· In the setting of multiple repairs, well-vascularized flaps should be utilized to protect suture lines.
SUGGESTED READINGS
Demetriades D, Theodorou D, Cornwall E, et al. Evaluation of penetrating injuries of the neck: prospective study of 223 patients. World J Surg. 1997;21:41–47.
Tisherman SA, Bokhari F, Collier B, et al. Clinical practice guideline: penetrating zone II neck trauma. J Trauma. 2008;64:1392–1405.