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Address reprint requests and correspondence: Department of Otolaryngology—Head and Neck Surgery, Vanderbilt University Medical Center, Suite 7209 Medical Center East, South Tower 1215, 21st Ave South, Nashville, TN 37232-8605.
External laryngotracheal trauma is a rare occurrence and requires specialized evaluation and management. Airway compromise from laryngotracheal injury can be catastrophic. The stability of an airway must be ensured with rapid and repeated clinical evaluation. Additionally, bedside and operative endoscopy combined with radiographic studies should guide treatment planning. Repair may include open reduction and internal fixation of laryngeal fractures, endolaryngeal mucosal repair (via either endoscopic or open approaches), endoluminal stenting, or open repair of laryngotracheal separation.
Laryngotracheal trauma presents a complex set of diagnostic and therapeutic challenges to even the most experienced otolaryngologists. Fortunately, it is a relatively rare occurrence with an estimated incidence of 1 in 30,000 emergency department (ED) visits in the United States each year.
Timely evaluation and identification of injuries is paramount, as mortalities related to penetrating and blunt laryngotracheal injuries range from 20%-40%, respectively.
Airway injury is frequently associated with complex multisystem trauma. However, despite protocols and algorithms designed specifically to evaluate for airway distress in this context, patients may initially have a benign airway exam, particularly those with blunt anterior cervical trauma.
However, over several hours, a combination of edema and fractured laryngotracheal framework can evolve to catastrophic airway compromise. Early, comprehensive physical examination, including flexible fiberoptic endoscopy, coupled with serial monitoring, is critical to effective management of acute laryngotracheal injury.
Schaefer has thoroughly described the optimal diagnostic algorithm for the initial management of acute external laryngotracheal trauma,
serving as the basis for our group’s workup and treatment algorithm. Summarizing Schaefer’s recommendations for acute management of airway trauma: in the setting of acute compromise, intubation can be considered when (1) the larynx and trachea are clearly intact and in continuity (2) the airway is visible to direct inspection by endoscopy in the ED or operating room, and (3) a highly experienced physician is preforming the intubation. When these criteria are not met, cricothyrotomy or tracheotomy are safer management options (cuffed, nonfenestrated tracheostomy tubes are preferred, as they minimize airflow over the injured larynx).
In the patient with a stable airway, computed tomography (CT) scanning of the airway has demonstrated benefit in the following scenarios: (1) patients with dysphonia or hemoptysis with a significant history of blunt force trauma to the anterior neck without significant abnormal findings on physical examination, (2) the condition and continuity of the endolarynx and trachea is not observable due to edema or hematoma, (3) the physician is uncertain about the extent of injury, and (4) when a physician capable of establishing an emergency airway is present.
Concurrent injury to the pharynx and/or esophagus is rare in both penetrating and blunt laryngeal trauma, however esophageal injuries are potentially devastating.
When evaluating a patient, barium swallow and contrasted CT esophagography are equivalent studies in patients without obvious esophageal injuries, although both are inferior to esophagoscopy.
Penetrating zone II neck injury: Does dynamic computed tomographic scan contribute to the diagnostic sensitivity of physical examination for surgically significant injury? A prospective blinded study.
Based on this, several authors (including our group) recommend rigid esophagoscopy in all patients undergoing surgical evaluation or treatment of external laryngotracheal injuries.
Preservation of the phonatory, respiratory, and deglutitive functions of the larynx require restoration of the complex architecture of cartilagenous framework, soft tissue, and epithelium. Failure to properly address injuries quickly may lead to permanent dysphonia
While each laryngotracheal injury is unique and must be treated as such, division of laryngeal injuries into an organized classification scheme helps to guide treatment planning and patient management. The Schaefer classification is the most widely employed tool.
Following initial airway stabilization, the otolaryngologist must assess integrity of the endolaryngeal mucosa and underlying cartilaginous skeleton. The primary objective in laryngeal fracture repair is to reestablish the cartilaginous framework of the airway. Commonly cited indications for repair include: full-height fractures of the midline and paramedian ala of the thyroid cartilage,
and displaced or comminuted fractures of the thyroid cartilage. As with the management of any osseous fracture, adequate reduction and fixation are necessary for return of normal laryngeal function. Suboptimal fixation can lead to cartilaginous malunion and subsequent loss of transverse and anterior-posterior diameters of the thyroid cartilage.
Exposure for open laryngeal fracture repair is best obtained via a neck incision made in a skin crease approximating the level of the cricothyroid membrane (Figure 1). Subplatysmal flaps are raised and the strap muscles are divided or retracted (Figure 2). Once the laryngeal cartilages are visualized, the perichondrium overlying the fracture(s) is incised (Figure 3). Perichondrial flaps that span 1-2 cm on each side of the fracture line(s) should be raised to gain adequate exposure for reduction and fixation (Figure 4). If a laryngofissure is necessary, it is important to raise the perichondrial flaps prior to making the cartilage incision, as it is more challenging to do this after it is completely incised. However, whenever possible, the endolarynx should be entered through existing fracture planes.
Fig. 1Exposure for open laryngeal fracture repair is obtained via incision in a skin crease at the level of the cricothyroid membrane.
Historically, suture and wire fixation techniques were employed for several decades for nearly all laryngeal fractures. Over time, however, animal experiments,
have demonstrated the inherent disadvantages of these methods of fixation. Normal swallowing and phonatory forces directed by extralaryngeal muscles are easily able to overcome suture or wire fixation and bend the segments out of plane.
Moreover, wired repairs of midline and paramedian thyroid cartilage fractures can result in decreased anterior-posterior diameter, secondary to flattening of the thyroid notch angle.
Building on experience from advances in reconstruction of maxillofacial trauma, the use miniplates in the fixation of laryngeal fractures began in the early 1990s and has evolved into the current standard of care given their proven benefits and outcomes.
The immediate restoration of rigid stability in plating facilitates improved alignment and decreases malunion and the risk of cartilage necrosis.
Plating
The principles used in plating laryngeal fractures are similar to those in maxillofacial bony trauma. A notable difference, however, is the softer density of cartilage compared to bone, particularly in younger individuals with non-ossified larynges. To compensate for this, some practitioners recommend using a drill bit one size smaller than the intended screw.
This practice increases the “pullout strength” of the screw, thereby preventing stripping. This also improves contact between the screw and cartilage, limiting room for movement.
Emergency screws may also be helpful in preventing stripping of screws. Cadaveric studies suggest the optimal combination for maximal pullout strength is achieved with a 0.76 mm bur/hole and a 1.5 mm diameter screw.
We commonly employ an otologic drill bur (1.0 mm) instead of a perforating dental drill to prevent inadvertent damage to the soft tissues on the inner surface of the cartilage.
We attempt to place screws into calcified areas such as the inferior thyroid cartilage or superior cricoid when possible (as these areas tend to be stronger than the surrounding uncalcified cartilages). The cricoid will typically only accommodate a single plate due to its smaller width.
We recommend using 2 screws on each side of a cricoid fracture plane to increase the stability of fixation.
Plate selection
Potential pitfalls of the use of metal plates include infection, palpability through the skin, extrusion, scatter effect on CT scans and interference with radiation therapy.
Developed in the 1990s, resorbable plates are made of lactic and/or glycolic acid polymers and are hydrolyzed to carbon dioxide and water over a period of 1-3 years.
strongly support efficacy and low morbidity of resorbable miniplates in laryngotracheal trauma. Resorbable plates with 1.5 and 2.0 mm thicknesses combined with 1.5 mm diameter screws have been used with good results.
The remainder of principles of resorbable plate application align those of their metal counterparts.
III. Laryngeal mucosal injuries
Surgical exposure
In endolaryngeal injury, the objectives of repair are distinct from those of rigid fixation in fracture management and are instead centered on restoring soft tissue integrity. In this setting, it is important to achieve mucosal coverage of exposed cartilage and maintain the size and shape of the glottis, as the risk of infection and graft failure increases when the epithelium is not in continuity.
Advancing expertise and instrumentation allow a significant number of endolaryngeal injuries to be managed endoscopically, thereby shortening recovery and limiting morbidities involved in open repair. However, if endoscopic exposure is inadequate (secondary to either edema of patient anatomy) or if there is a cartilage fracture that requires repair, an open approach via laryngofissure is preferred.
The exposure for a laryngofissure is identical to that outlined above for plating a laryngeal fracture. Once perichondrium is elevated off the thyroid cartilage, a small incision is made in the cricothyroid membrane. A curved, blunt hemostat (with the tips up/anterior) is inserted through the incision and carried superiorly while gently lifting the thyroid cartilage anteriorly (Figure 5A). Lifting the larynx positions the hemostat in the anterior commissure, decreasing the likelihood of vocal cord injury (Figure 5B). The thyroid cartilage is then slowly incised in the midline with a scalpel, taking care to avoid the vocal cords (Figure 5C). Heavy scissors or an oscillating bone saw may be used if the cartilage is ossified. The endolarynx is then accessed (Figure 6A), facilitating direct mucosal repair (Figure 6B). Upon closure, the vocal cords are resuspended onto the cut edges of the thyroid cartilage with nonabsorbable monofilament suture (Figure 7A). A keel or endoluminal stent may be left in the anterior commissure and sutured to the skin if there is bilateral loss of anterior vocal fold epithelium (thereby raising the risk of web formation, Figure 7B). The edges of the thyroid cartilage are reapproximated and closed with suture or miniplates as in the setting of a fracture (Figure 8). On closure, careful attention must be paid to return the vocal cords to their original positions to prevent height discrepancies and subsequent deficiencies in phonation.
Fig. 5(A) A small incision is made in the cricothyroid membrane and a curved, blunt hemostat (with the tips up/anterior) is inserted through the incision and carried superiorly while gently lifting the thyroid cartilage anteriorly. (B) Lifting the larynx positions the hemostat in the anterior commissure, decreasing the likelihood of vocal cord injury. (C) The thyroid cartilage is then slowly incised in the midline with a scalpel, taking care to avoid the vocal cords.
Fig. 7(A) Upon closure, the vocal cords are resuspended onto the cut edges of the thyroid cartilage with nonabsorbable monofilament suture. (B) A keel or endoluminal stent may be left in the anterior commissure and sutured to the skin if there is bilateral loss of anterior vocal fold epithelium.
When repairing these injuries, denuded mucosa should be draped as close to its original position to the extent possible. Simple interrupted sutures using lightweight (5-0 and 6-0) absorbable suture (fast-absorbing plain gut) are useful to maintain the mucosa in these positions as it heals.
Endoluminal stenting
Given the tenuous nature of suture and wire fracture fixations, stents have been used historically to bolster repaired fractures from the internal surface and maintain fixation. As contemporary miniplates have improved the stability of fixation, stents are now employed primarily when severe endolaryngeal tissue loss leaves mucosa physically unavailable for reapproximation.
Stents are commercially available in many shapes, however we routinely fashion our stents from the cut end of a Montgomery T-tube (given its easy accessibility). The decision to use a preformed vs customized stent relates to surgeon preference without clear superiority to either approach. The overriding principle in stent selection is balancing a snug fit without exertion of excessive pressure (thereby limiting mucosal or cartilage necrosis).
when defects exist after primary closure. The grafts can be sewn directly into the traumatic deficit, or for severe and extensive tissue loss, the skin graft may be sewn (epidermal surface facing the stent) around the stent and secured within the larynx via external sutures.
In the rare instances of severe disruption of the anterior commissure, we suspend the vocal ligament to the exterior thyroid cartilage perichondrium. We would also use a small keel placed at the time of the initial repair.
Stents should be secured within the larynx with monofilament synthetic sutures through the laryngeal ventricle and secondarily through the cricothyroid membrane to limit migration.
Severely comminuted fractures often require both internal stenting and external fixation due to potential for separation of cartilage fragments with normal movements of the larynx when swallowing. When fractures can be stabilized without an internal lumen keeper and endolaryngeal mucosal injuries are minimal, stenting should be avoided as healing outcomes may be suboptimal.
Just as stent materials are highly variable, their duration of use also varies considerably. Most mucosal healing occurs within 7-10 days. Most large series support 2-3 weeks stent placement
Traumatic separation of the trachea from the larynx is the most severe airway injury. In unique cases the separation may be easily visible through a neck laceration and allow for rapid intubation through the distal tracheal segment. However, as with other blunt injuries, patients may initially be asymptomatic and clinical suspicion for separation may be low. Physicians need to maintain a high index of suspicion with “clothesline” mechanism of injury, or physical exam evidence of anterior neck blunt trauma. Symptoms may quickly progress, and practitioners must be prepared to rapidly assess and secure a patient’s airway. Laryngotracheal separation presents unique challenges to initial management. Orotracheal intubation is contraindicated due to the risk of retraction of the trachea into the thorax upon neck extension. In this setting, an awake, low tracheotomy is preferred. Formal repair of the separation usually follows immediately once the airway is secured. These patients also have a high incidence of bilateral true vocal fold (TVF) paralysis. The tracheostomy stays in place in the perioperative period until glottic function can be confirmed.
Surgical exposure
If the neck is not already open due to a laceration or emergent tracheotomy, the exposure approach described above would be applicable in this situation, except for need to obtain a wider (more inferior) operative field. Similar to the technical aspects of tracheal reconstruction in benign stenosis, traction sutures (2.0 prolene) should be placed in the distal tracheal segment early to prevent retraction into the chest during the repair.
Techniques for repair of laryngotracheal separation have remained stable over time with primary anastomosis being the preferred method. Medium to heavyweight (2-0 or 3-0) absorbable sutures (both vicryl and PDS) have been effective without differences in anastomotic dehiscence rates between approaches.
The use of endoluminal stents after surgical repair of laryngotracheal separation is variable (in 30% of studies reviewed). In this setting they are most commonly employed when concomitant laryngeal fractures
Because of the substantial physical force necessary to create laryngotracheal separation, the likelihood of recurrent laryngeal nerve (RLN) injury is high.
As such, we make a significant effort to assess preoperative glottic function. If edema, or an indwelling ETT limits our evaluation initially, we will assess the larynx under a light plan of anesthesia after securing the tracheostomy. In our experience, poor preoperative laryngeal function portends a poor long-term outcome, and this information helps postoperative counseling.
V. Postoperative considerations
Postoperative care for all patients with laryngotracheal trauma includes admission with regular observation, humidified oxygen, and 30° head-of-bed elevation.
We place a dobbhoff tube™ in all patients with laryngeal injury or laryngotracheal separation. All patients undergo postoperative swallow evaluation by a speech-language pathologist (via fluoroscopic examinations) 2-3 days after repair. The timing of postoperative evaluation is also influenced by the presence of pharyngeal or esophageal injury, the degree of endolaryngeal injury, and the placement of an endoluminal stent.
Postoperative antibiotic use is variable and should depend on intraoperative findings and the expected postoperative course. If the laryngeal mucosa has been breached, we employ prophylactic systemic antibiotics with coverage for oral flora (Gram-positive bacteria and anerobes). Exposed cartilage should be prophylactically treated to prevent chondritis. Fluoroquinolones, either topical or systemic, may be used, as they provide good cartilage penetration.
We also utilize aggressive oral hygiene (dental care and Peridex soloution 4 times daily) for 2 weeks postoperatively.
We utilize proton pump inhibitors aggressively in the perioperative period. Systemic steroid use should be individualized. In patients who undergo a surgical repair that includes a tracheostomy, we avoid postoperative systemic corticosteroids due to the negative effects on wound healing (given the established alternative airway).
In laryngotracheal separation injuries, neck movement should be restricted for several days following open repair. Excessive extension may disrupt a delicate anastamosis and necessitate revision. We utilize an Aspen™ or Miami J™ cervical collar to limit neck extension (rather than a Grillo stitch).
Conclusion
Stability of the airway in the setting of laryngotracheal trauma is of the utmost importance. Rapid and repeated physical examination is crucial to ensure this objective. Once an airway is secured and laryngotracheal injury is identified, a decision must be made about the need for operative management. Guided by established therapeutic algorithms, multiple established endoscopic and open surgical approaches allow individualizing treatment to each unique patient.
Disclosure
The authors reported no proprietary or commercial interest in any product mentioned or concept discussed in this article.
References
Schaefer S.D.
The acute management of external laryngeal trauma. A 27-year experience.
Arch Otolaryngol Head Neck Surg.1992; 118: 598-604
Penetrating zone II neck injury: Does dynamic computed tomographic scan contribute to the diagnostic sensitivity of physical examination for surgically significant injury? A prospective blinded study.
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