TITLE: Laryngeal Trauma
SOURCE: Grand Rounds Presentation, UTMB, Dept. of Otolaryngology
DATE: September 02, 2003
RESIDENT PHYSICIAN: Michael Underbrink, MD
FACULTY PHYSICIAN: Anna Pou, MD
SERIES EDITORS: Francis B. Quinn, Jr., MD and Matthew W. Ryan, MD
"This material was
prepared by resident physicians in partial fulfillment of educational
requirements established for the Postgraduate Training Program of the UTMB
Department of Otolaryngology/Head and Neck Surgery and was not intended for
clinical use in its present form. It was prepared for the purpose of
stimulating group discussion in a conference setting. No warranties,
either express or implied, are made with respect to its accuracy, completeness,
or timeliness. The material does not necessarily reflect the current or past
opinions of members of the UTMB faculty and should not be used for purposes of
diagnosis or treatment without consulting appropriate literature sources and
informed professional opinion."
Introduction
External laryngeal trauma is a relatively uncommon injury
estimated at approximately 1 in every 30,000 emergency room visits. This is fortunate because injury to the
larynx can result in serious airway problems and impaired voice production if
not diagnosed promptly. The initial concern
with acute laryngeal trauma is securing the airway. Vocal function, while certainly of secondary
importance in terms of preservation of life, is often determined by the
effectiveness of the initial management.
Therefore, it is imperative that the otolaryngologist be familiar with
the diagnosis and treatment of this rare, but very serious type of injury.
Anatomy and Physiology
Fortunately the larynx is well protected by the mandible,
the sternum and the flexion mechanism of the neck. The primary functions of the larynx are to
provide an airway, protect the lower respiratory tract, and produce the
voice. The larynx can be divided into
three areas: supraglottis, glottis and
subglottis. Support is maintained by the
hyoid bone, thyroid cartilage and cricoid cartilage. The supraglottis is less dependent on
external support and contains abundant soft tissue and redundant mucosa. The glottis relies heavily on external
support and the coordination of cricoarytenoid mobility and neuromuscular
activity to support the airway and provide phonation. In the adult, the airway is narrowest at the
glottis. Therefore, injury at this level
may seriously compromise airway support.
The subglottis is supported by the only circular cartilage in the
larynx, the cricoid, which is the narrowest point of the neonatal and infant
airways.
Mechanism of Injury
The type of injury can be classified as either blunt or
penetrating. Blunt injuries are commonly
the result of motor vehicle crashes. The
laryngeal skeleton is compressed between a foreign object (i.e., steering wheel
or dashboard) and the anterior aspect of the cervical spine. This splays the alae of the thyroid cartilage
and with enough force, may fracture the cartilage often in a vertical median or
paramedian nature. Other types of blunt
trauma include sports related injury, strangulation, assaults or the
clothesline injury associated with snowmobiles or all terrain
vehicles. The force of the injury can
cause significant soft tissue and/or cartilage disruption with minimal external
signs of trauma. Blunt trauma may also
cause dislocation of the cricoarytenoid joint or damage to the recurrent
laryngeal nerves with resultant impaired vocal cord mobility.
Penetrating trauma to the larynx may occur
secondary to knife or bullet wounds. The
extent of injury varies with the type of assault weapon, and it is important to
realize that other associated injuries, such as neurological, vascular, or
esophageal, are more common in these situations.
Initial Evaluation
Initial management should follow ATLS principles. Securing an airway takes precedence over
other problems. Injury to the cervical
spine should be suspected in these patients until proven otherwise. There is some controversy over airway
management in these patients, but most authors recommend tracheotomy under
local anesthesia for patients exhibiting respiratory distress. Attempts at oral
or nasotracheal intubations in these patients may result in further damage to
an already tenuous airway.
Cricothyroidotomies should be avoided in the setting of laryngeal trauma
as this may contribute to further injury.
Special considerations exist in the pediatric patient population. Due to the smaller dimensions of the
pediatric airway and potential for soft swelling edema with laryngeal trauma,
it is recommended that they undergo tracheotomy over a ventilating bronchoscope
in the operating room. In patients with
no acute breathing difficulties, a detailed history and careful physical
examination can be obtained.
Presenting symptoms of laryngeal trauma may include a change
in the quality of voice, pain, dysphagia, odynophagia, hemoptysis and/or
stridor. Inability to tolerate the
supine position is a concerning symptom with regard to airway stability. Schaefer reports that the symptom correlating
with the most severe injury is impaired respiration. Fuhrman, et al., reports the most reliable
symptom as hoarseness. Classic signs of
external laryngeal trauma include hoarseness, subcutaneous emphysema and
hemoptysis. The most reliable symptoms
reported by Fuhrman were tenderness and subcutaneous emphysema. Other physical exam findings, such as
anterior neck contusion and tracheal deviation may also occur. Associated injuries including cervical spine,
esophageal and vascular injuries must be considered and evaluated.
In stable patients, flexible fiberoptic laryngoscopy in the
emergency room should be performed. CT
scan, direct laryngoscopy, bronchoscopy and esophagosopy are used selectively
based on initial fiberoptic exam findings. It has become increasingly important
to categorize patients by the severity of trauma according to fiberoptic exam
and CT findings in order to aid with the management of their injuries. Suggested protocols for treatment are
offered by categorization into four groups established by Schaefer and Close
with the addition of a fifth group for cricotracheal separation by Fuhrman et
al.
Laryngotracheal Injury
Classification
Group I injuries include minor endolaryngeal hematoma, edema
or laceration without detectable fracture.
Group II injuries have edema, hematoma, minor mucosal disruption without
exposed cartilage, and nondisplaced fractures noted
on CT scan. Massive edema, mucosal
disruption, displaced fractures, exposed cartilage and/or cord immobility
qualify as Group III injuries. Group IV
injury is the same as group III with the addition of two or more fracture
lines, skeletal instability or significant anterior commissure
trauma. The group V category includes
complete laryngotracheal separation.
Radiologic evaluation
In the stable patient, after the airway has been evaluated,
a CT scan of the larynx can be obtained. A CT scan is not necessary in a
patient presenting with clear indications for surgery, such as active bleeding,
hemoptysis, need for emergent surgical airway,
exposed cartilage and significant lacerations on laryngoscopy,
or air escaping through the neck wound.
Conversely, patients with minimal trauma and a normal exam will not
likely benefit from a CT scan of the larynx.
In patients with significant laryngeal trauma and intermediate exam
findings, CT scanning should be performed to determine the integrity of the
laryngeal framework. It should be noted
that some authors routinely obtain CT scans even for severe trauma before proceeding
to the operating room as a “roadmap” of the patient’s injuries. The entire cervical spine should be evaluated
radiographically.
Angiography and Gastrografin esophagrams may be indicated in selected cases, especially
in the event of significant penetrating trauma to the area.
Nonsurgical Management
Laryngeal injuries may be treated medically or surgically
depending on initial fiberoptic laryngoscopic and CT scan findings. A patient can be treated medically with close
observation if the injury will resolve without surgical intervention and the
airway is stable. Group I injuries can
be safely managed with a minimum of 24 hours of close observation, head of bed
elevation, voice rest and humidification of inspired air. Antibiotics are recommended with disruption
of the laryngeal mucosa. Treatment with
anti-reflux medication is also initiated.
Although not proven, systemic steroids are often given to reduce
laryngeal edema. Nasogastric tube
feedings should be considered if significant mucosal lacerations are
present. Serial flexible fiberoptic
examinations should be performed to evaluate the airway and healing prior to
discharge.
Surgical Management
The indications for surgical management may range from the
need to establish an airway to open reduction and internal fixation of
laryngoskeletal fractures. Penetrating
traumas are more likely to require open exploration than blunt traumas. Group II through group V patients will
usually require some form of surgical intervention. Surgical options fall into one of three
categories: endoscopy alone, endoscopy
with exploration, and endoscopy with exploration and stenting. If there is any doubt about the extent of
injury endoscopy should be performed.
Indications for surgical exploration include: large mucosal lacerations, exposed cartilage,
multiple or displaced cartilaginous fractures, vocal cord immobility, fractured
cricoid, disruption of the cricoarytenoid joint, and lacerations involving the
free margin of the vocal cord or anterior commisure. A vertically oriented fracture of the median
or paramedian thyroid ala may significantly alter the stability of the
laryngeal skeleton and usually necessitates ORIF. Tracheotomy should be performed in patients
with injuries of this extent and should be lower than usual (fourth to fifth
ring) via a vertical incision (better exposure in the case of laryngotracheal
separation).
When laryngeal exploration is indicated, it should be
performed within 24 hours of the injury in order to maximize airway and
phonation results. A horizontal skin
incision is made at the level of the cricothyroid membrane and subplatysmal
flaps are elevated. The strap muscles
are then divided in the midline and the laryngeal skeleton is exposed. The larynx can then be explored via a midline
thyrotomy or via a vertical fracture within 2 to 3 mm of the midline. The thyroid laminae are retracted laterally
to visualize the endolarynx. All exposed
cartilaginous and submucosal tissues are then covered with mucosa working
posteriorly to anteriorly. Primary
closure is almost always possible and debridement should be minimized. Closure is performed with absorbable suture
with knots outside the laryngeal lumen to prevent granulation. Displaced arytenoid cartilages should be
reduced. The anterior commissure should
be reconstituted by using 4.0 sutures to suspend the anterior true vocal cords
to the outer perichondrium of the thyroid cartilage. The thyrotomy can then be reapproximated with
nonabsorbable suture, wire or rigid miniplates.
Fractures of the cartilages are reduced and can be
stabilized using a variety of materials, including stainless steel wires,
nonabsorbable suture, and miniplates. If
the fracture is comminuted, small fragments of cartilage with no intact
perichondrium are removed to prevent chondritis. Adaptation miniplates have the theoretical
advantage of immediate stability of the larynx (less need for endolaryngeal
stenting), ability to bridge large gaps (comminuted fractures), and easier
restoration of the preinjury geometry of the laryngeal framework.
Endolaryngeal stenting
is reserved for wounds involving disruption of the anterior commissure, massive
mucosal injuries and comminuted fractures of the laryngeal skeleton. Stenting reestablishes the normal scaphoid
shape of the anterior commissure, stabilizes severely
comminuted fractures and prevents web formation and stenosis. A variety of stents can be used including a
shortened Portex endotracheal tube, manufactured silastic stents, or a finger
cot filled with sponge rubber. Stents
should reach from the false cords to the first tracheal ring and conform to the
shape of the endolarynx. The stent
should be stabilized within the larynx and allow movement with the larynx
during swallowing. A heavy,
nonabsorbable suture is passed through the stent and larynx at the ventricle
and another at the cricothyroid membrane and tied over buttons outside the
skin. The stent should not be left
longer than 2 to 3 weeks. Removal is
performed under general anesthesia with endoscopy and additional procedures for
removal of granulation tissue as necessary.
The unique injury of laryngotracheal separation usually
results in immediate death. Occasionally
the airway may maintain patency with an intact mucosal layer. Although successful intubation attempts with
bronchoscopy have been reported, it is usually more safely managed by emergent
tracheotomy. Bilateral recurrent
laryngeal nerve injury and subglottic stenosis are common with this injury. Surgical repair requires permanent sutures
between the cricoid and second tracheal ring for airway support. This may be difficult with concomitant
cricoid fracture after internal fixation.
Severe wounds involving extensive tissue and framework loss
of the supraglottic or hemilarynx can be managed using various partial
laryngectomy procedures to restore function.
Total laryngectomy is a last resort and is reserved for situations where
the basic elements of the laryngeal skeleton and investing soft tissue are not
usable for repair.
Outcomes
The ultimate quality of airway, voice and swallowing are
important considerations following repair of external laryngeal trauma. Airway status is poor if the patient remains
cannulated, fair with mild aspiration or exercise intolerance and good if it
resembles preinjury status. Voice can be
considered poor if it represents aphonia or whisper, fair if it is functional
but changed (hoarse), and good if normal.
Swallowing function is either normal or abnormal from the subjective
reports of the patient. Generally,
conservatively managed injuries fare better than surgical ones in large part
due to the differences in severity of the initial insult. The use of endolaryngeal stents tends to
decrease the quality of voice without affecting the overall airway status. Also, the less time the stent is left in
place, the more favorable the result.
Vocal cord paralysis adversely affects outcomes with regard to both
airway and voice. Improved results are
also shown with the earlier the timing of the repair (less than 48 hours from
injury being significant).
Conclusion
External laryngeal trauma is a rare injury that can be
managed in a systematic fashion. Early
recognition is important for both initial preservation of life as well as
long-term airway and vocal function. The
signs and symptoms hoarseness, subcutaneous emphysema, and pain with a history
of laryngeal trauma should prompt a timely evaluation of the larynx and airway
support. Flexible fiberoptic
laryngoscopy followed by CT scans and surgical procedures as deemed necessary
are standard in the initial evaluation.
Associated cervical spine, vascular and esophageal injuries should be
excluded. Treatment, either medical or
surgical (with/without stenting) is based on the site and extent of injury.
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