Fig. 31.1
Injuries to multiple structures in the neck are common with penetrating neck trauma given the close proximity of major vascular, aerodigestive, nervous, and endocrine structures
The most common categorization for penetrating trauma to the neck divides the neck into three zones. Zone I extends from the clavicles to the cricoid cartilage, Zone II spans from the cricoid cartilage to the angle of the mandible, and Zone III is between the angle of the mandible and the skull base. Zone II is most commonly injured, and the evaluation and management of these injuries remain the most controversial. The management of asymptomatic or moderately symptomatic injuries to Zone II has evolved over time. Historical management of all Zone II penetrating injuries, formed by military experience during conflict, was mandatory operative exploration and direct repair given the high incidence of injuries to vascular and aerodigestive structures. Mandatory exploration remained the standard of care for civilian patients for several decades, even though 40–89 % of these operations were nontherapeutic. Many surgeons began to advocate for selective operative management for asymptomatic civilians presenting with Zone II penetrating neck trauma given the different injury patterns sustained from lower velocity weaponry.
While some series suggest that clinical exam alone may accurately determine which asymptomatic patients require further diagnostic studies after penetrating neck trauma, we believe that a low threshold for imaging studies is necessary given the high morbidity and mortality of missed injuries. High-resolution computed tomography angiography (CTA), multiplanar computed tomography (CT), and/or endoscopic modalities (i.e., bronchoscopy, esophagoscopy) may be utilized to further evaluate patients. With overall mortality rates as high as 40–50 %, penetrating neck trauma remains a challenging disease process and requires skillful and timely surgical care.
31.1 Airway Management
Patients presenting obtunded or in respiratory distress after penetrating neck trauma require immediate intubation. Patients with a patent airway and spontaneous breathing may not require emergent intubation, but a high level of clinical suspicion for injury is required. Any delay in diagnosis of a laryngotracheal injury may lead to edema and hematoma formation with subsequent airway obstruction and urgent need for a surgical airway. Signs and symptoms of airway injury may be readily apparent such as massive subcutaneous emphysema, air bubbles in the wound, and inability to phonate. More subtle signs may include hoarseness, cervical ecchymoses, voice changes, and odynophagia. Prehospital cervical collar used in penetrating neck trauma may not always be necessary and may indeed be harmful by obscuring penetrating wounds and making management of the airway more difficult. If a cervical collar is present, it should immediately be removed to fully assess the airway and neck.
A review of 52 patients with penetrating laryngotracheal injury demonstrated that 48 % of patients required immediate airway control and 80 % of these airways were accomplished through oral endotracheal intubation. In an older series of penetrating laryngotracheal injuries, 56 % required immediate airway control, but only 44 % of these airways were accomplished through oral endotracheal intubation. In both of these series, the most common clinical manifestations of injury were stridor, respiratory distress, and crepitus.
Oral endotracheal intubation via direct laryngoscopy is the preferred route for airway control in patients with laryngotracheal injury. While this method is expedient and successful in many patients, oropharyngeal swelling or facial fractures may limit visualization under direct laryngoscopy. Furthermore, neuromuscular blockade, commonly used to achieve oral endotracheal intubation, should be avoided in cases of penetrating neck trauma in order to maintain the patient’s spontaneous respiratory drive. In cases of suspected laryngotracheal injury, the most experienced individual available should perform the procedure. In some cases only one attempt at intubation will be possible. In the event of failure to orally intubate, other options for airway control must be readily available.
Controlled awake fiberoptic nasotracheal intubation with topical anesthesia is a safe and effective alternative when performed by an individual skilled in this procedure. Blind nasotracheal intubation should not be attempted in any patients with airway injury as this may compound injuries. Furthermore, nasotracheal intubation should not be attempted in patients with basilar skull fractures, frontal sinus fractures, or cribriform plate fractures. Other options for control of the airway may include videolaryngoscopy (e.g., GlideScope) or intubation over a gum elastic bougie (e.g., Eschmann). Routine use of video laryngoscopy has increased, with the potential benefits that all providers have the same visualization of the airway, and there may be a higher first-pass intubation rate in trauma patients. Laryngeal mask airway (LMA) may be considered, but this is not a definitive airway; these typically do not work well when anatomy is distorted, and placement may cause additional injury either via direct trauma or insufflation pressures above an airway injury.
Surgical airway equipment should always be readily available in the event translaryngeal techniques fail. Cricothyroidotomy is the procedure of choice in the emergent setting and can be accomplished quickly and with minimal morbidity to surrounding structures. Both horizontal and vertical incisions are described, but we prefer a vertical incision in all patients and in particular in the setting of tracheolaryngeal injury (Fig. 31.2a). A vertical incision allows flexibility to identify the proper level of the airway and avoids the anterior jugular veins. A tracheostomy tube is the preferred device (Fig. 31.2b, c), but an endotracheal tube may also be used. Care should be taken to avoid main stem bronchus intubation if an endotracheal tube is used. Emergent tracheotomy should only be used in cases of suspected complete laryngotracheal separation or when injury is located below the cricothyroid membrane. For large tracheal injuries requiring an emergent airway, the tracheostomy may be placed directly through the anterior tracheal wound.
Fig. 31.2
(a) A vertical cricothyroidotomy incision allows flexibility to identify the proper level of the airway and avoids the anterior jugular veins. (b, c) A tracheostomy tube is the preferred airway device for cricothyroidotomy
31.2 Injury Classification
Definitive care of laryngotracheal injury requires a comprehensive understanding of the anatomy of the larynx and trachea. Airway injuries are best classified based on their relation to the vocal cords. Supraglottic injuries are typically associated with vertical fractures of the thyroid cartilage with or without fracture of the cricoid cartilage. Glottic injuries may involve the thyroid cartilage but can also involve the true vocal cords, thyroarytenoid muscles, and aryepiglottic bands. Subglottic injuries involve the lower thyroid cartilage and cricoid cartilage and are potentially the most dangerous injuries. Complete loss of the airway may result from subglottic stenosis related to cricotracheal separation, and emergent tracheostomy is required in this setting. Glottic and supraglottic injuries are more difficult to repair, especially with respect to voice quality. Early engagement of a head and neck surgeon is important in these cases once the airway has been secured.
31.3 Injury Evaluation and Management
Laryngotracheal injury is uncommon, but patients presenting with these injuries almost universally require operative management. An older prospective study of 223 patients with penetrating neck trauma found that only 6.3 % of patients had laryngotracheal or pharyngoesophageal injury. A recent single institution 13-year review identified 22 patients specifically with penetrating cervical or thoracic tracheal injury, and 86 % required emergent neck exploration.
Indications for immediate surgical exploration in patients with penetrating neck trauma include expanding hematoma, exsanguinating hemorrhage, hemodynamic instability, and massive subcutaneous emphysema. Data suggest that patients without immediate surgical indications should undergo complete physical examination and symptom assessment, anteroposterior (AP) chest plain film, and AP and lateral neck film. Asymptomatic patients may be observed with serial physical exam every 6–8 h for at least 24 h before discharge. Clinical exam is at least 95 % sensitive for identifying laryngotracheal injuries that require operative repair. For patients with mild or moderate signs and/or symptoms or those with a change in exam, high-resolution CTA should be obtained as the diagnostic study of choice. CTA may be utilized for all patients in whom injury is suspected if the modality is available. If there is no evidence of vascular, neurologic, or aerodigestive injury on CTA, observation is warranted.
If there is physical exam or CT evidence or clinical suspicion for injury, endoscopic evaluation should be pursued. Direct or indirect laryngoscopy, fiberoptic bronchoscopy, and esophagoscopy may be used to evaluate for injury to the aerodigestive structures. Contrast esophagography modalities may also be used in addition to or instead of esophagoscopy. Once all injuries have been identified, definitive surgical care may include operative exploration and repair or nonoperative management. Many patients with small glottic, supraglottic, or pharyngeal lacerations or hematomas may be managed nonoperatively with NPO status, antibiotics, and speech/language therapy. Follow-up contrast esophagography may be necessary to identify any persistent pharyngeal or esophageal leak before resuming an oral diet.
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