Incidence

External laryngeal trauma is rare. It has a population incidence of 1 in 137,000 in adults⁴ and accounts for 0.5% of trauma admissions in children.⁷ Other studies estimate the incidence of this injury to be between 1 in 5000⁸ and 1 in 30,000⁹ emergency room visits.

Etiology

The larynx is well shielded by the mandible superiorly, the sternum inferiorly, the sternomastoid muscles laterally, and the spinal column posteriorly. Further protection is afforded through its mobility. It is however susceptible to crushing anterior cervical trauma, which compresses the organ against the spinal column (Fig. 70-2). Laryngeal injury is also compounded by the process of calcification that begins during the third decade of life and affects men to a greater degree than women.¹⁰ Being often asymmetric in respect to the extent of calcification of both the inner and outer surfaces of the thyroid cartilage and each hemi-lamina,¹¹ laryngeal calcification increases the likelihood of fractures after trauma and creates stress risers that can cause framework comminution. Motor vehicle accidents have historically been the main cause of external laryngeal trauma.¹² The injury typically occurs when a person not wearing a seat belt or wearing only a lap belt is subjected to rapid deceleration, which thrusts the hyperextended neck onto the dashboard or the steering wheel.¹³ Other causes of blunt external laryngeal trauma are clothesline injury (in which the rider of a motorcycle encounters a fixed horizontal object at neck level), sports-related injuries,¹⁴ and suicidal or homicidal strangulation. Penetrating laryngeal trauma is due predominantly to interpersonal violence in civilian practice and is the main cause of laryngeal injuries sustained in the theater of war.¹⁵ Over the past four decades the composition of laryngeal trauma in the United States has changed substantially, due on the one hand to reductions in speed limits, mandatory seat belt laws, and better public education—reducing the incidence of blunt trauma due to motor vehicle accidents—and on the other hand to an increase in penetrating trauma secondary to a greater use of guns and knives (Fig. 70-3).^{2,3,6,8,9,16–21}

Figure 70-2. Impact of anterior cervical trauma on the larynx. Top, Uncalcified thyroid cartilage may spring back. Bottom, Calcified cartilage may shatter, and the larynx appears flattened.

Figure 70-3. Change in the relative composition of blunt and penetrating laryngeal trauma as reported in several sources from 1965 through 2005.

(Data from references 2, 3, 6, 8, 9, and 16–21.)

Diagnosis

Examination and Initial Management

Examination and initial management of laryngeal trauma should be part of primary and secondary surveys according to Advanced Trauma Life Support guidelines, to ensure that concomitant injuries are not missed (Table 70-2).⁴ The over-riding priority is to establish a safe airway with cervical spine protection, which may, and often does, necessitate performing an emergency tracheotomy with the use of local anesthesia. Endotracheal intubation is not a preferred method of airway control in laryngeal trauma, because it can exacerbate a laryngeal injury²⁵ and precipitate total airway obstruction. Endotracheal intubation can be particularly difficult to perform in the presence of concomitant maxillofacial injuries in a patient with an immobile neck. If endotracheal intubation has been performed, it is converted at the earliest opportunity to a tracheotomy to prevent long-term laryngeal injury. In selected cases transtracheal jet ventilation or cricothyroidotomy may be a helpful temporizing measure. No manipulation of the neck is permissible until the cervical spine has been “cleared”—that is, until injuries to the cervical spine have been ruled out in a systematic manner.

Table 70-2 Concomitant Primary Diagnoses Recorded along with Laryngeal Trauma

The neck is inspected for evidence of injury such as skin abrasions, bruising, and entry and exit wounds in penetrating trauma, and is palpated for crepitations, laryngeal tenderness, and any obvious changes in laryngeal anatomy, such as loss of the prominence. Open wounds should not be explored at this stage because instrumentation may restart hemorrhage. Flexible nasoendoscopy is then performed, and the oropharynx and hypopharynx are examined for injuries. The laryngeal mucosa is examined for lacerations and hematomas, and particular care is taken to assess the vibratory edge of the vocal cords and the anterior commissure. Arytenoid adduction is examined during phonation, and abduction is assessed by asking the patient to sniff. Impairment of arytenoid mobility may be secondary to structural damage or due to recurrent laryngeal nerve injury. Note is taken of any exposed or protruded cartilage or submucosal distortion of the framework. A sign of cartilaginous injury is failure of the vocal cords to meet in the same horizontal plane.

Use of Computed Tomography

In our practice, multislice computed tomography (CT) (Fig. 70-4) is performed in all patients presenting with “impending airway obstruction” once their airways have been secured, and in those patients with “stable airway” who are found, on flexible nasoendoscopy to have endolaryngeal abnormalities, because imaging may reveal further injuries not readily identifiable with flexible nasoendoscopy. CT scanning can be deferred only in those patients with a history of relatively minor trauma to the neck, no laryngeal tenderness or surgical emphysema, stable airway, and the finding of minimal laryngeal injuries on flexible laryngoscopy. It is important to appreciate that laryngeal trauma is associated with a cervical spine fracture at a rate approaching 10%.⁴ At the same time, injuries that occur close to the cervical spine are known to be more likely to mask a spinal injury than injuries further away.²⁶ We take the view therefore that all but the most minor of laryngeal injuries constitute a “distracting injury” and mandate cervical spine radiography under National Emergency X-Radiography Utilization Study (NEXUS) criteria (Box 70-1).²⁷ Our practice of using CT to clear the cervical spine irrespective of plain radiography findings is informed by a growing body of evidence demonstrating a much higher sensitivity for CT over plain radiography in diagnosing spinal injuries.^28,29 Overall, therefore, detailed radiologic imaging of the larynx is available in the majority of patients with laryngeal trauma both because of primary laryngeal indications and as a by-product of “clearing” of the cervical spine.

Figure 70-4. A, Computed tomography shows a hematoma involving the right vocal fold (arrows) with the thyroid cartilage intact. The injury was completely resolved with only medical management. B, Fracture of the right anterior thyroid lamina with angulation (A, arrow) is seen. The management consisted of open reduction and internal fixation.

Classification

Laryngeal trauma can be classified according the Schaefer-Fuhrman^25,30 (Table 70-3) or Lee-Eliashar³¹ system. We use the Schaefer-Fuhrman system but also formally and separately document the extent of injuries to the laryngeal mucosa and framework, the vibratory mechanism, and the laryngotracheal complex (Table 70-4).

Table 70-3 Schaefer-Fuhrman Classification of Laryngeal Trauma

Table 70-4 A Systematic Approach to Documenting Laryngotracheal Injuries and Determining the Need for Surgical Intervention

Management

Airway Management

The first priority in managing laryngeal trauma is to assess and secure the airway while protecting the cervical spine. We take a stepwise approach to securing the airway based on information available at the different stages of clinical assessment (Fig. 70-5

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Voice Evaluation
2. Central Neural Auditory Prosthesis
3. Nasal Fractures
4. Malignant Tumors of the Larynx

Stay updated, free articles. Join our Telegram channel

Join