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Dental injury accounts for the majority of post-anesthetic airway injuries.
Mild sore throat is a common and usually self-limited complaint after endotracheal intubation or laryngeal mask airway placement.
Severe sore throat is very uncommon and should raise suspicion for airway injury.
Postoperative hoarseness and changes in phonation should raise suspicion for possible arytenoid cartilage dislocation.
Airway trauma is a well-known potential complication of anesthesia that can result in significant morbidity and mortality. According to the American Society of Anesthesiologists Closed Claims Database, approximately 6% of the 4,460 claims analyzed were recorded as “airway injury” with the most frequent sites of injury consisting of the larynx (33%), pharynx (19%), and esophagus (18%).[1] Injury results from a combination of instrumentation of the airway with rigid equipment (laryngoscope, endotracheal tube [ETT], laryngeal mask airway), skill level of the anesthesia provider, and patient anatomy (i.e. micrognathia, inadequate neck extension or mouth opening, airway mass).
The most common symptoms of airway trauma in the postoperative patient include pain, bleeding, dysphonia, stridor, dysphagia, and/or odynophagia. Review of the anesthetic record and physical examination of the patient are important in diagnosis of airway injuries in the postoperative setting. In this chapter we review different types of airway trauma, mechanism, presentation, diagnosis, and management.
Nerve injuries
Mechanisms:
Endotracheal intubation: injury to hypoglossal nerve, laryngeal nerve, or internal branch of the superior laryngeal nerve due to direct pressure with laryngoscope blade, rupture of piriform recess by an ETT, malposition of endotracheal tube cuff, or improper ETT size.[2]
Facemask ventilation: injury to the mandibular branch of the facial nerve, or mental branch of the trigeminal nerve from direct mechanical compression with the mask.[2]
Laryngeal mask airway (LMA): injury to lingual, hypoglossal, or recurrent laryngeal branch of the vagus nerve from direct mechanical compression (specific cause unknown but could be overinflated LMA, too small sized LMA, use of nitrous oxide, or prolonged LMA use).[2,3]
Presentation: within 48 hours of surgery and depends on the nerve injured.
Lingual nerve injury: loss of taste, and of sensation over the anterior tongue.
Hypoglossal nerve injury: difficulty in swallowing.
Mandibular branch of the facial nerve: facial nerve palsy.
Mental nerve injury: lower lip numbness.
Recurrent laryngeal nerve injury: dysarthria, stridor, postoperative aspiration, hoarseness (unilateral injury), respiratory obstruction (bilateral injury).[2,3] Hoarseness is a common postoperative complication with an incidence of 14.4% to 50%.[4]
Superior laryngeal nerve injury: numbness of the upper surface of the larynx.
Diagnosis: clinical based on exam and patient symptoms. Direct visualization of vocal cords (e.g. with fiber-optic scope) may help to diagnose recurrent laryngeal nerve injury.
Management: reassurance for most nerve injuries as they usually resolve spontaneously over a period of days to months.[3] If recurrent laryngeal nerve is injured, patient may be at risk for aspiration.[5] An otolaryngology consult should be considered.
Dislocations
Temporomandibular joint (TMJ) dislocation
Mechanism: pressure applied to the angle of the mandible during facemask ventilation, or during routine tracheal intubations when excessive force is applied to the joint when opening the mouth. Patient with facial skeletal abnormalities are at an increased risk.[6]
Presentation: pain, trismus.
Diagnosis: history of dislocation in OR, clinical symptoms.
Treatment: soft diet for 2 weeks. If symptoms persist after 2 weeks, an oral surgery consult should be considered.[6]
Mechanism: tearing of cricoarytenoid ligaments resulting in vocal cord immobility on affected side. Occurs during direct laryngoscopy with inadequate visualization, use of a large ETT, or rarely with an LMA. Risk factors include elderly, systemic joint diseases (i.e. rheumatoid arthritis), difficult airway, use of blind intubation technique.[6]
Presentation: persistent hoarseness after extubation, “breathy” voice, odynophagia, weak cough, aspiration.[7]
Diagnosis: direct visualization or CT scan.
Management: otolaryngology consult for reduction of dislocation as soon as possible to avoid permanent damage.
Nasopharyngeal injuries
Types of injuries include false passage of tube into posterior pharyngeal wall, dislodgement of nasal polyps or turbinates, adenoidectomy, injury of the nasal septum, or mucosal lacerations.
Mechanisms: placement of rigid/semirigid devices such as nasogastric and nasotracheal tubes, as well as nasal trumpets, in the nasopharynx.
Presentation: epistaxis, pain, edema, hyposmia, or anosmia (reduced ability or inability to detect odors).[2]
Diagnosis: direct visualization.
Management: reassurance, otolaryngology consult for persistent epistaxis that may require nasal packing.
Injuries of oral cavity/pharynx/larynx
Injuries can range from superficial mucosal lacerations to internal carotid artery thrombosis or pseudoaneurysm, thrombosis of the internal jugular vein, or pharyngoesophageal perforation which can result in mediastinitis.[8] Other injuries include dental injuries (incidence greater than 1 in 4,500 anesthetics[9]), tongue lacerations, perforation of the piriform recess or epiglottic vallecula, hematoma of vocal cord (usually on left).[2,10] The most frequent injury of the larynx is to the recurrent laryngeal nerve, causing vocal cord paralysis (see “Nerve injuries” above). Most commonly, however, patients complain of a sore throat: 7% to 12% of patients whose airway was maintained with an LMA, 14.4% to 90% of patients who had an ETT, and 15% to 22% who had a plastic oral airway and facemask report a sore throat in the postoperative period.[9,11,12] Women tend to report sore throat more often than men do.[11]
Mechanisms:
Videolaryngoscope injuries: insertion of ETT and/or stylette into soft tissues of pharynx/larynx causing laceration likely due to placement of tube without a period of direct visualization until the tip comes into view on video screen.
Laryngoscope blade, ETT, stylette, tube exchanger, bougie, Yankauer suction, naso or orogastric tube, oral or nasal airway, transesophageal echo probe, temperature probe, LMA can all cause trauma with routine insertion/use.
Presentation: depends on location and severity of injury but can include pain, bleeding, odynophagia, hematoma, mediastinitis, subcutaneous crepitus, pneumothorax, and chest pain.[6,8]
Diagnosis: history, direct visualization, radiologist consultation for advice on imaging. Diagnosis of perforations may be delayed, as early symptoms, such as sore throat, deep cervical neck pain, chest pain, and cough, are non-specific.[1]
Sore throat: reassurance as it usually resolves spontaneously. Ice chips or a gargle with a topical drug such as benzydamine hydrochloride can provide symptomatic relief.[13]
Dental injuries: avulsed teeth should be placed in saline and an oral surgery consult should be called, as the tooth should be re-implanted within one hour. A partial or complete dental fracture should be evaluated by an oral surgeon postoperatively for consideration of restoration.[2,6]
Minor lacerations: usually self-limited and do not require surgical intervention. For deeper lacerations patients should remain NPO for 48 hours and be placed on broad spectrum antibiotics. Otolaryngology consult is suggested for more severe injuries that may need to be surgically repaired. Those patients necessitating surgical repair should be NPO for at least one week. If a hematoma is present, antibiotics should be administered, and it should be drained if it is large.[6]
Pharyngoesophageal perforations: the high mortality associated with these perforations warrants early intervention. If a perforation is suspected a surgical consult should be made, the patient should remain NPO, and broad spectrum intravenous antibiotics should be started.[14]
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