The larynx is a complex anatomic structure and a properly functioning larynx is essential for breathing, voice, and swallowing. Laryngeal trauma is often associated with other injuries, including intracranial injuries, penetrating neck injuries, cervical spine fractures, and facial fractures. Although uncommon, laryngotracheal injuries may lead to life-threatening airway emergencies. Because laryngeal injuries are rare, even surgeons with a great deal of experience in managing maxillofacial trauma have limited exposure to management of laryngeal and tracheal injury. This article reviews a protocol for the evaluation, management, and treatment of these injuries in the trauma patient.
Key points
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The key step in treatment of any laryngeal injury is the establishment of a secure airway.
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Early intervention (within 24–48 hours) is an important factor for improved patient outcomes (functional speech, swallowing, and airway patency).
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An awake tracheostomy is the airway of choice with grade II or higher laryngeal injuries.
Introduction
The larynx is a complex anatomic structure and a properly functioning larynx is essential for breathing, voice, and swallowing. Injuries to the larynx and trachea can result in significant and potentially fatal consequences. Laryngeal trauma is often associated with other injuries, including intracranial injuries (17%), penetrating neck injuries (18%), cervical spine fractures (13%), and facial fractures (9%). Laryngeal injuries are rare, occurring in only 1 of 5000 to 137,000 emergency room visits and among only 1 in 445 patients with severe injuries. Because of this, even surgeons with a great deal of experience in managing maxillofacial trauma have limited exposure to management of laryngeal and tracheal injury. This article discusses the evaluation, diagnosis, and management of patients with laryngeal and tracheal injury.
Classification of laryngeal injuries
Several classification systems have been described to assist in developing an algorithmic approach to managing these difficult and rare injuries. These classification systems have been based on mode of injury, types of tissues involved in the injury, anatomic locations of injury, and severity of the injury. Modes of injury have been divided into blunt and penetrating injuries. Whereas blunt injuries have been described as being associated with greater length of hospitalization, our experience has been that penetrating airway injuries, often associated with ballistic wounds, are much more likely to be associated with greater endolaryngeal disruption. The types of tissues involved have been divided into hard and soft tissue injuries. Locations of injuries have been classified as injuries that affect the supraglottic larynx, the glottis, and subglottic larynx.
Lynch was the first to classify traumatic injuries based on location. In 1969, Nahum described laryngeal injuries based on injury location and likelihood of recovery with and without intervention. In 1980, Schaefer and colleagues developed what has become the most popular classification system to assess the severity of such injuries. This classification describes laryngeal injuries on a scale of I-IV. Schaefer’s classification was later modified by Fuhrman and colleagues to include laryngotracheal separation ( Table 1 ) and again by Verschueren and colleagues in 2006 to include the use of computed tomography (CT) imaging in staging ( Table 2 ). In this article, the discussion of the initial evaluation and management of a patient with laryngeal trauma is within the framework of the Legacy Emanuel Classification, as outlined by the algorithm in Fig. 1 . However, the principles are generalizable and can be applied to whichever system the reader finds most helpful in their practice.
| Stage | Injury |
|---|---|
| I | Minor laryngeal hematoma, edema, laceration; no detectable fracture |
| II | Edema, hematoma, mucosal disruption with no exposed cartilage, nondisplaced fractures |
| III | Significant edema, noted mucosal disruption, exposed cartilage with or without cord immobility, displaced fractures |
| IV | Significant edema, noted mucosal disruption, exposed cartilage with or without cord immobility, displaced fractures with 2 or more fracture lines, skeletal instability/anterior commissure trauma |
| V | Complete laryngotracheal separation |
| Stage | Diagnostic Findings | Management |
|---|---|---|
| I | Minor airway symptoms ± Voice changes No fractures Small lacerations |
Observation Humidified air Head of bed elevation |
| II | Airway compromise Nondisplaced fractures No cartilage exposure Voice changes ± Subcutaneous emphysema |
Immediate awake tracheostomy if airway not already secured in the field Humidified air Head of bed elevation ± ORIF |
| III | Airway compromise Edema Mucosal lacerations Palpable laryngeal fractures Exposed cartilage Subcutaneous emphysemas Voice changes |
Immediate awake tracheostomy if airway not already secured in the field Direct laryngoscopy Exploration and ORIF |
| IV | Airway compromise Mucosal lacerations Exposed cartilage Palpable displaced laryngeal fractures with skeletal instability Subcutaneous emphysemas Voice changes |
Immediate awake tracheostomy if airway not already secured in the field Direct laryngoscopy Exploration/ORIF Consider stenting |
Initial evaluation and initial management
The initial evaluation of a patient suspected of having laryngeal or tracheal injury, as with any trauma, begins with the primary survey as outlined in Advanced Trauma Life Support algorithms. Because the larynx and trachea are critical components of the airway, prompt identification and management of these injuries are prioritized. This begins with a quick survey of the injuries. Patients with either blunt or penetrating injury to the neck must be ruled out as having airway injury. The mechanism of the injury should also raise one’s suspicion. In a review of laryngeal injuries from 1992 to 2004, high speed motor vehicle accidents were the most common mechanism (49%), followed by sports-related injuries (29%). Certain mechanisms of injury, such as hanging, gunshot wounds, or work-related high-energy injuries to the neck, should obviously generate an elevated level of suspicion.
Stable Versus Unstable Airway
The first essential question is to establish whether the airway is secured and whether the patient is stable. If the patient is stable and protecting their airway, there is time for a more deliberate examination. This is important because occult trachea-laryngeal disturbance can occur with minimal external signs of trauma.
The initial airway physical examination starts with visual inspection for swelling, soft tissue injury overlying the airway, loss of anatomic landmarks in the neck, and signs of troubled breathing. A cursory examination of the patient’s voice is performed, noting the presence or absence of stridor and/or dysphonia. Next, use gentle palpation to assess for subcutaneous emphysema and palpable disruption of the hyoid bone, thyroid cartilage, cricoid, and trachea. The most common findings on physical examination include subcutaneous air, hoarseness, tenderness of the anterior neck to palpation, and stridor.
A fiberoptic examination may also be performed if timing allows and other injuries do not take precedence. The fiberoptic examination may help to verify that the patient’s airway is stable enough for transfer to the scanner. An awake fiberoptic examination also has the benefit of allowing visualization of the larynx in function. This examination is meant to be performed quickly and efficiently so as to not impede overall trauma management. The evaluating surgeon must keep in mind that traumatized airways that appear stable tend to deteriorate over time because of the onset of edema, expansion of hematomas, and other contributory factors.
The next step is a CT scan of the head and neck, which is done in addition to CT scans of chest, abdomen, and pelvis that are routinely performed as part of the trauma survey ( Fig. 2 ). In stable patients with penetrating neck injury, a CT angiogram is also included to evaluate for vascular injury. CT imaging allows for rapid and accurate identification of hard tissue injuries to larynx and trachea and identification of soft tissue air emphysema.
If the airway is not secure and/or is unstable, or the patient is unstable for other reasons, the patient is taken emergently to the operating room where securing the airway followed by stabilization of the patient is the immediate priority. Traditionally, this is via an oral endotracheal intubation. However, if the patient has a known laryngeal or tracheal injury, oral endotracheal intubation can fail, particularly because of false passage or further disruption of the injured airway. Although securing the airway trumps any other priority, in this situation the most ideal airway is a tracheostomy, performed awake with either mask or laryngeal mask airway support, as the situation allows. If endotracheal intubation is the route chosen, a fiberoptic intubation with a pediatric bronchoscope is one of several tools to be considered by the anesthesiologist. In the presence of endolaryngeal lacerations, the primary risk is that of intubating a blind submucoperichondrial pouch that produces immediate and total airway obstruction. The stat surgical airway that follows not only risks the patient’s life but can also worsen the existing laryngotracheal injuries.
Once the airway is secured and the patient is stable, the next step in the evaluation involves physical examination, CT imaging (if not already performed), and panendoscopy. Anatomically, the larynx is subdivided into the supraglottic larynx, glottic larynx, and subglottic larynx, and trachea. Injury can occur at any and all of these levels. Therefore, the examination is performed in such manner where each of these areas are carefully inspected. It is important to remember that, particularly with blunt trauma, disruption of the laryngeal framework can occur without obvious external findings. For example, disruption of the cricoarytenoid joint and shortening of the true vocal cord can occur with blunt trauma and manifest itself with vocal changes, without external signs of injury. If left untreated, the dislocated arytenoid may scar in that position resulting in permanent, more difficult to correct vocal disturbance. It is widely agreed on that early identification and treatment of laryngeal injuries yields superior results, ideally within the first 24 to 48 hours if circumstances allow.
Nondisplaced Versus Displaced Cartilage Fractures
The CT scan answers an essential branch point in our management algorithm, which is whether or not there are displaced fractures of the cartilaginous larynx. The CT scan is especially valuable because it can detect occult fractures missed on examination.
Patients without cartilage fractures or with nondisplaced cartilage fractures are managed in a more conservative manner. Patients with nondisplaced cartilage fractures are carefully assessed for vocal disturbances. Signs of voice changes should prompt a fiberoptic nasopharyngoscopy to assess for endolaryngeal injury. If the patient has already been intubated or has a tracheostomy, a direct laryngoscopy under anesthesia is performed instead. While under anesthesia, a bronchoscopy and esophagoscopy are also performed to assess the full extent of injury.
If no signs of endolaryngeal injury are observed, the patient is observed and receives supportive care. If the laryngeal examination demonstrates mucosal injury, consideration should be given to surgical repair versus serial endoscopic examination. Mucosal lacerations are repaired primarily through a thyrotomy (laryngofissure) approach, or in some cases, endoscopically. Denuded laryngeal cartilage that is not amenable to primary closure is treated with a thyrotomy approach coupled with use of a laryngeal stent or laryngeal keel.
If the CT scan identifies displaced cartilage fractures, these are treated with open reduction and internal fixation. Before this, many such patients benefit from having the airway secured with an awake tracheostomy. This avoids the need for endotracheal intubation, which is challenging and further disrupts the displaced cartilage fractures. Once the airway is secured, direct laryngoscopy is performed to assess for endolaryngeal injury, as discussed previously. Consideration is given to including esophagoscopy and/or bronchoscopy. If there are no signs of endolaryngeal injury, the surgeon may proceed with open reduction and internal fixation of the displaced cartilage segments. If there are signs of significant endolaryngeal injury, repair them via laryngofissure approach followed by open reduction internal fixation of the cartilage fractures.
Anatomic considerations
Epiglottis
The epiglottis, as the superior extent of the supraglottic larynx, connected by ligaments to the hyoid bone and thyroid cartilage, is significantly affected by laryngeal trauma. Hyoid fractures can result in an epiglottic hematoma ( Fig. 3 ). An epiglottic hematoma quickly results in stridor, difficulty with speech, and eventually dyspnea and potential airway embarrassment. Partial or complete avulsion of the epiglottis can also occur with severe hyoid and thyroid fractures. This manifests as dysphagia and aspiration.
