Reproduced with permission from Bacha EA et al.1

Reproduced with permission from Bacha EA et al.1

Cervical Injury. Damage to the larynx and cervical trachea from blunt injury may include fracture with or without displacement of the hyoid, the supraglottic larynx, the infraglottic larynx, the cricoid cartilage, and the cervical trachea (Figure 9-1). A variable amount of trachea may be elevated into the neck by cervical hyperextension at the time of injury, depending on the age of the patient. In the young, the larynx may be severely contused or otherwise injured without actual fracture of the more flexible cartilages. In older patients, stiffening and calcification render the larynx more vulnerable to fracture. Mucosal tears and avulsions are seen. Vocal cords and arytenoids may be torn and displaced. It is important to consider the spectrum of possible injuries when examining an acutely traumatized patient.4 Separation of the airway may be partial or complete. The points of actual rupture of the cervical airway are most commonly between the cricoid and trachea and in the upper trachea. Blunt trauma rarely produces clean cuts, but rather produces complexes of injuries, including, for example, cricotracheal separation with concurrent fracture of the cricoid cartilage, and avulsion of mucosa from the anterior surface of the posterior cricoid plate (Figure 9-2).

In 19 patients with laryngotracheal disruption, 11 due to direct impact and 8 due to strangulation, Couraud and colleagues identified 14 complete separations below the cricoid or first ring.3 Nine cricoid fractures were seen. The mucosa retracted in all patients to expose cricoid cartilage. One or both recurrent laryngeal nerves may be temporarily or permanently damaged. Fourteen of Couraud's patients suffered bilateral recurrent nerve damage and 4 were unilateral. Concomitant tears of the esophagus may occur. Avulsion of the trachea from the cricoid may be accompanied by transverse laceration of the anterior esophagus from the pharynx, where it is attached to the cricoid posteriorly, or by completely circumferential separation. Subluxation of cervical vertebrae, with or without injury to the spinal cord, may occur concomitantly. With penetrating wounds of the neck and thoracic inlet, and even with blunt trauma, the spectrum of potential injuries includes major vascular injuries.

Penetrating cervical wounds, chiefly due to stab or gunshot wounds, may injure the trachea as one of several structures damaged. Bilateral recurrent laryngeal nerve division is less common than in complete tracheal separation due to blunt injury. Although dissenting voices are raised, surgical exploration of penetrating cervical wounds still seems to be the judicious course.

Thoracic Trachea and Bronchi. Fracture or laceration of the thoracic trachea, carina, or main bronchi following closed chest injury may be seen in children and young adults without rib or sternal fractures. The young thorax can absorb major compressive trauma and rebound without skeletal fractures. In the older patient, clavicular and upper rib fractures and the number of rib fractures correlate with the likelihood of tracheobronchial injury.5 It is likely that a sudden increase of intrabronchial pressure against the closed glottis, or rapid deceleration, produces some airway injuries. Blunt injuries to the thoracic trachea are most common in the lower trachea and vary widely from complete transection to a partial horizontal tear. Vertical splitting of the trachea from the carina upward occurs, running anteriorly through cartilages and/or posteriorly up the membranous wall, either in its center or laterally along the junction with the cartilages. Injury to the lower trachea may be accompanied by partial or complete shearing of one or both main bronchi.

figure 9-1 Cervical laryngotracheal blunt trauma. A, Supraglottic tears and fractures. B, Transglottic injuries. C, Cricoid fracture. D, Avulsion of trachea from cricoid. E, Laceration or tear of trachea. Adapted from Harris HH. Management of injuries to the larynx and trachea. Laryngoscope Ï972;82:Ï924-9.

figure 9-1 Cervical laryngotracheal blunt trauma. A, Supraglottic tears and fractures. B, Transglottic injuries. C, Cricoid fracture. D, Avulsion of trachea from cricoid. E, Laceration or tear of trachea. Adapted from Harris HH. Management of injuries to the larynx and trachea. Laryngoscope Ï972;82:Ï924-9.

figure 9-2 Blunt injury to the neck in motor vehicle accident. The distal end of the trachea is completely separated from the larynx. The forceps holds a posterior and lateral full thickness mucosal flap (arrow) which was avulsed from the anterior surface of the posterior cricoid below the arytenoids. The endotracheal tube (ET) has been introduced through a tracheostomy below the level of transection. Since both recurrent laryngeal nerves were severed, it was evident that a tracheostomy would be necessary postoperatively and hence the ET was placed through this location. The mucosal flap was resutured into the posterolateral laryngeal defect. A laryngeal mold was also used. The esophagus, which had been separated from the pharynx, was reanastomosed. Strap muscle was interposed between laryngotracheal and pharyngoesophageal suture lines.

Lobar or segmental bronchi may also be lacerated or separated by crush injuries, usually accompanied by deep parenchymal laceration. From a review of 183 tracheobronchial blunt injuries reported between 1970 and 1990, Symbas and colleagues noted that 74% were transverse ruptures with 4% in cervical and 12% in thoracic trachea, 25% in the right main bronchus, 17% in the left main bronchus, and 16% in lobar bronchi (Figure 9-3).6 Of longitudinal tears (18%), 6.5% were in the cervical trachea, 10% in the thoracic trachea, and 1.5% in main bronchi. The 8% remaining were complex, involving the trachea and right or both main bronchi. Most injuries occur within 2.5 cm of the carina. Kiser and colleagues, in a review of 265 patients who suffered blunt tracheobronchial injuries, confirmed a greater frequency of right-sided injuries, both overall and at the time of diagnosis and treatment.7 They found that bronchial rupture occurred within 2 cm proximal to the carina in 76%, and that 43% occurred in the right main bronchus.

Recurrent laryngeal nerve injury is rare in thoracic tracheal trauma. Also rare but equally as important is concurrent laceration of the esophagus, often longitudinally. Esophageal injury should be considered in every posterior laceration of the trachea, since esophageal injury from blunt trauma is unlikely to occur by itself. It probably results from sudden forceful compression of the trachea and esophagus against the vertebrae, such as that from steering wheel impact. The injury occurs more often in young patients, with or without upper rib fractures. An elastic chest wall seems to favor such injury. Injury is most common in the lower trachea but may occur in the neck. The communication may be instantly established or occur later as traumatized tissues necrose. Potentially lethal mediastinitis may be a consequence of an overlooked intrathoracic esophageal laceration.

Failure to recognize acute injury to the airway because of distraction due to catastrophic associated injuries, or failure to manage acute airway injury appropriately, may lead to cicatricial obstruction and other sequelae, days or months later. Such problems are often correctable but with greater difficulty and complications.

Tracheobronchial Lacerations after Intubation. Lacerations of the trachea and bronchi may be produced by single and double lumen endotracheal tubes. The injuries are in the membranous wall and are usually linear. Postoperative mediastinal or subcutaneous emphysema may indicate an unrecognized intraoperative endotracheal intubation laceration. In a careful analysis of these lacerations, Massard and colleagues found predominant injuries in the lower trachea and main bronchi, and in the case of single lumen tubes, along the right membranous cartilaginous junction.8 Cervical laceration occurs less often. Overinflation of cuffs rather than stylets or tube tips appears to cause the injuries. Repositioning a tube that was originally placed in the right main bronchus without deflating the cuff may be an important factor. Short women, with correspondingly narrower airways, appear to be more at risk. Lacerations also occur from the placement of tracheostomy tubes when insertion is difficult. Mediastinal or subcutaneous emphysema and pneumothorax are harbingers.

The modalities of surgical repair and conservative treatment are discussed in Chapter 31, "Repair of Tracheobronchial Trauma." In general, small lacerations may be safely managed conservatively, but larger ones are best repaired surgically.8,9

Injury to the membranous wall of the trachea above the carina or of the left main bronchus has been noted in about 1 to 2% of patients undergoing transhiatal esophagectomy.10 These have been treated by suture, reinforcement with pleura or pericardium, and effective buttressing with the gastric tube neoesophagus.

figure 9-3 Blunt tracheobronchial injuries: type and location. Adapted from Symbas PN et al.6 LMB = left main bronchus; RMB = right main bronchus.

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