eMedicine Specialties > Trauma > Head and Neck Trauma

Penetrating Neck Trauma: Workup

Author: Daniel Mark Alterman, MD, RN, Resident Physician, Department of Surgery, University of Tennessee Graduate School of Medicine
Coauthor(s): Brian James Daley, MD, MBA, FACS, Associate Program Director, Professor, Department of Surgery, Division of Trauma and Critical Care, University of Tennessee School of Medicine; Eugene Y Cheng, MD, FCCM, Consulting Staff, Department of Anesthesiology, The Permanente Medical Group; Val Selivanov, MD, Consulting Staff, Administrative Chief, Department of Surgery, Kaiser Permanente of Santa Teresa
Contributor Information and Disclosures

Updated: Sep 9, 2008

Workup

Laboratory Studies

• Hemoglobin concentration is useful to evaluate for the immediate need for transfusion and to document the starting point for future comparison.
• A blood specimen for typing is useful should transfusion be required. As patients who have had prior transfusions become alloimmunized, early recognition of antibody formation is essential to provide compatible blood products.
• A toxicologic screen is indicated for the patient with an altered sensorium. This is important to help differentiate the altered sensorium of intoxication from a neurologic etiology following penetrating neck trauma with an arterial injury component.

Imaging Studies

• Cervical anteroposterior and lateral radiography is used to evaluate for vertebral bony injury; retained foreign bodies; and foreign body deformity, location, size, and number.
• Four-vessel cerebral angiography is indicated with clinical evidence of significant vascular injury (ie, hard signs) in zone I and zone III, as well as in selectively managed zone II injuries. Physical examination findings reliably guide the use of invasive testing for suspected zone II vascular injury. In fact, the percentage (about 1%) of missed vascular injuries using physical examination screening criteria is similar to the false-negative rate for angiography. Data from Ferguson and colleagues suggest that, in the absence of hard vascular signs with a zone III injury, angiography is not necessary.²  This concept holds true for many types of suspected arterial injury. This represents a dramatic change in evaluation, as angiography was previously mandatory for all penetrating zone III injuries.
• Hypotension and exsanguination should prompt operative exploration in most centers. Certain centers that have in-house angiographers may proceed to the angiography suite for injuries in zone I and zone III despite hypotension or hemorrhage. Angiography remains the criterion standard for defining arterial anatomy and injury complexes, with an accuracy close to 100%.
• Arteriography demonstrates a low yield (<1%) of findings that alter treatment in asymptomatic patients. Arteriography usually is performed using a digital subtraction angiography (DSA) technique that reduces the amount of contrast required and yields a superior computer-manipulated image for evaluation.
• Helical computed tomographic angiography is less invasive and is showing promise in defining vascular neck injury. Possibly, in the future, this technique may replace angiography.
• Two-dimensional Doppler studies are a noninvasive alternative to angiography to evaluate vascular injury in critical areas (principally in zone II). Its role in zone III evaluation is quite limited, given the obvious anatomic limitations of ultrasound in this region. This study typically incorporates a static B mode image of the interrogated vessel in combination with real-time ultrasound and Doppler velocity determination coupled with spectral analysis. This is covered in the umbrella term Duplex. Three-dimensional images for reformation are increasingly available but require costly imaging systems that may not be readily available in the emergency department. Such tests may be best used in stable patients with zone II injuries without any signs of vascular injury to complete the examination of the regional vital structures.
• Esophagography is essential to evaluate for an esophageal perforation. Selecting the oral contrast medium for esophageal injury detection is controversial. One school of thought contends that oral iodinated aqueous contrast media better demonstrates perforations and anastomotic leakage with less risk of complications than barium; the sensitivity of this technique in detecting esophageal injury increases from 70-89% when combined with esophagoscopy. The other school of thought contends that aqueous contrast media is hypertonic and, if extravasated into the mediastinum, induces a local inflammatory reaction. Barium solution is inert in the mediastinum and has been used for decades within the tracheobronchial tree for contrast bronchography prior to the advent of flexible bronchoscopy.
• Computed tomography (CT) scan is a study that can evaluate many structures at a time and that is enhanced with the use of intravenous nonionic contrast media. If available, helical or spiral CT scans permit multiplanar views and 3-dimensional reconstructions. A CT scan is excellent for helping to define and diagnose a laryngeal injury. A CT scan can also be useful to help define a missile tract.  A CT scan does not increase the sensitivity of detecting an esophageal injury. If an esophageal injury is suspected, esophagoscopy is the procedure of choice.   
• CT angiography (CTA) is gaining acceptance as an adjunctive screening tool.  A review by Woo and colleagues reports that the use of CTA is associated with less operative exploration, less negative explorations, and reduced use of invasive studies, such as conventional angiography.¹  Physical examination findings supplemented by CTA should have a prominent role in the selective management of penetrating neck injuries.  CTA has replaced angiography as the initial study of choice in the vascular evaluation of a neck injury.     
• The improved spatial resolution of the multidetector CT scan has improved the diagnostic capability and the accuracy of this modality, further supporting it as the initial study of choice for civilian injury. 
• Renewed interest as to the optimal management of wartime penetrating neck injuries has been addressed by Fox and colleagues in the delayed assessment of war casualties at Walter Reed Army Medical Center.³  A significant number of delayed evaluations found injuries, and retained missile fragments, were a limitation to accurate assessment at the zone of injury with CT examination. They assert that, for the military injury, arteriography remains the criterion standard.
• The advantage of magnetic resonance imaging is not elucidated clearly for penetrating neck injuries; continual evaluation and monitoring of trauma patients who are in potentially critical condition presents a problem during this procedure.  
• Even when readily available, time constraints of magnetic resonance angiogram (MRA) limit its use in the acute phase of traumatic evaluation.

Diagnostic Procedures

• Direct laryngoscopy - For evaluation of oropharyngeal and tracheal injuries
• Flexible bronchoscopy - For delineation of tracheal and bronchial injuries
• Esophagoscopy - Flexible esophagoscopy can be used to detect an esophageal injury with less risk of procedure-related complications than rigid esophagoscopy (ie, rupture and complications from general anesthesia). Concerns exist regarding the introduction of oropharyngeal flora into the tissue planes of the neck when performing upper endoscopy in the presence of a perforation because visualization of the central lumen is aided by continuous gas insufflation through the endoscope.

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• Penetrating Injuries of the Neck (Otolaryngology and Facial Plastic Surgery)