An LTI can be classified as external or internal by direction of force, and an external LTI can be classified as open or close. External laryngeal injuries are estimated to occur at an incidence of 1 in every 13,7000 ED visits [1, 2]. The main mechanism of injury is thought to be due to falls or blunt trauma. In an epidemiological survey of head and neck injuries and trauma in the United States in 2011, 64% of head and neck injuries were attributed to falls or blunt trauma and 41.8% of these were open wounds [3]. Penetrating neck injuries are less common and account for 5–10% of traumatic injuries in adults [4], although Sachdeva et al. showed that penetrating neck injuries are more common than blunt trauma [5]. Moreover, about 20% of LTIs are associated with other injuries [3]. Therefore, multiple traumatic injuries, including penetrating external LTIs, are quite rare and are managed only by a team by trauma specialists and otolaryngologists.
The initial assessment and management for neck injuries include a pre-hospital and a general trauma survey with primary consideration given to assessing and securing the airway. According to several studies, the most common symptoms of neck injury are respiratory distress, subcutaneous emphysema, hoarseness of voice, neck tenderness, stridor, dysphasia, and hemoptysis [6–9]. Patients need to be intubated immediately when signs of airway obstruction occur, such as increasing stridor, aphonia, and dyspnea with the use of accessory muscles of respiration [2, 10]. However, the decision to intubate or not at the scene needs careful consideration because of the risk of mucosal soft tissue expansion and airway obstruction resulting from blind intubation. In a systematic review and meta-analysis of 21 studies, more than half of the studies showed that pre-hospital intubation was significantly associated with a higher mortality rate [11]. Thus, intubating the patient using bronchofiberscopy, which allows observation of the inner trachea, inserting a thinner endotracheal tube, and inserting a tracheostomy tube from the laceration remain to be much safer options. In our case, his airway was secured because there was no deviated tissue and blood clot which may obstruct airway due to complete laryngotracheal separation and no vessel injury. Therefore, the patient was transferred to the hospital without having been intubated.
In terms of the time course, a delayed definitive repair may result in higher chances of sequelae such as laryngeal stenosis, scarring, and granulation tissue formation. Hence, it must be performed ideally within 24 hours and no later than 48 hours after trauma [12, 13]. Emergency physicians and trauma surgeons should also perform an initial assessment and management for severe conditions that may compromise the airway or breathing. Furthermore, in the event of securing the airway, a collaboration between ED and ENT doctors is necessary to improve patient evaluation and management. In our case, while it is true that the patient had no airway obstruction or blood vessel injury, the cooperation between ED and ENT doctors also had a significant impact on patient survival, even though the patient had multiple trauma.
A CT scan, especially a or CT angiography, is necessary for classifying the injury and choosing the treatment option. Although a penetrating external LTI usually requires surgical intervention for exploration and primary repair, treatment of blunt external or internal LTI depends on the severity of mucosal, cartilage, or bone injury. Therefore, a more detailed evaluation by a thin-slice scan and angiography is needed.
There are several classifications for LTI according to the severity, site (supraglottic, glottic, or subglottic), and tissue injured (cartilage, mucosa, ligaments, nerves, or joints). The American Academy of Otolaryngology-Head and Neck Surgery has accepted the Schaefer classification system as the most useful tool because it allows the clinician to make treatment decisions based on the severity of injury (Table 2) [14, 15]. Under the Schaefer classification system, Group 1 injuries are usually managed using nonoperative methods, such as head elevation, voice rest, cool humidification, steroids, antibiotics, and anti-reflux medication. Although the frequency is different, tracheostomy is required for Group 2 to 4 injuries, while surgical repair is required for Group 3 and 4 injuries. For Group 5 injuries, although tracheostomy and surgical repair are also required, the main theme is only securing the airway and performing a primary repair. After that, a complex repair is often performed if the patient’s general condition worsens. In our case, the patient’s injuries were classified as Group 5 on the Schaefer classification system and were managed as mentioned above.
Table 2
Schaefer classification system
| Group | Description of injury | Method of evaluation |
| Ⅰ | Minor endolaryngeal hematomas or lacerations without detectable fractures | Flexible laryngoscopy |
| Ⅱ | More severe edema, hematoma, minor mucosal disruption without exposed cartilage, or non-displaced fractures | Direct laryngoscopy and esophagoscopy |
| Ⅲ | Massive edema, large mucosal lacerations, exposed cartilage, displaced fractures or vocal cord immobility | Direct laryngoscopy and esophagoscopy |
| Ⅳ | Same as group 3, but more severe with disruption of anterior larynx, unstable fractures, two or more fracture lines, or severe mucosal injuries | Direct laryngoscopy and esophagoscopy |
| Ⅴ | Complete laryngotracheal separation | Urgent airway evaluation |
LTIs are also classified using Roon and Christensen’s modification, which divides neck injuries into three zones according to anatomy. Zone Ⅰ is from the level of the clavicles to that of the cricoid cartilage. Zone Ⅱ is from the level of the cricoid cartilage to that of the angle of the mandible. Zone Ⅲ covers from the level of the angle of the mandible to the base of the skull [16]. Although unstable patients require emergency surgical hemostasis and securing the airway, mandatory exploration is necessary for stable symptomatic zone Ⅱ injuries, and radiographic CT angiography can assist with visualization of the abnormality in stable zone Ⅰ and Ⅲ injuries using zone-based management algorithm. However, zone Ⅰ and Ⅲ injuries are anatomically difficult to approach. Blunt LTIs require a thin-slice CT scan because they result in tissue disruptions instead of open wounds. Objects that cause penetrating injuries, such as a knife, bullet, fragment of iron or wood, and pen, are likely to cause more tissue loss than blunt injuries [3]. In particular, it is difficult to close wounds if there is loss of cartilage tissue. Although Pandurangarao et al. reported that cricoid cartilage defect could be repaired using conchal cartilage graft, the treatment can sometimes be long term [17]. Most penetrating injuries consist of a horizontal or oblique deep cut that results in an open wound, especially if it was a sharp and horizontal laceration due to a suicide attempt by knife-stabbing [3, 18]. In our case, wound closure was presumed to occur at a comparatively early time because despite the occurrence of complete laryngotracheal separation, the sharp and horizontal lacerations were not accompanied by significant tissue losses. Although jugular vein or vertebral artery injuries are common with neck injuries, the findings from our case indicate that wound closure may occur early in patients who attempted suicide by knife-stabbing and developed an open penetrating external LTI without blood vessel injuries. Thus, a need arises for a new classification that considers the sharpness of the wound, the degree of tissue loss and disruption, and the nature of the object that caused the injury.
