Abstract
We report a case of tracheal ring fracture after external laryngeal manipulation for assisting intubation because of difficult laryngoscopy during induction of anesthesia. The patient was a 64-year-old female suffering from a large multinodular goiter scheduled to undergo general anesthesia with endotracheal intubation for thyroidectomy. Laryngoscopy was performed, which did not visualize the glottis. With application of forceful external laryngeal manipulation, intubation was successfully achieved on the third attempt. But on skin incision and tissue exposure, a single fractured site on the second tracheal ring was noted. Fiberoptic bronchoscopy was performed and showed the tracheal mucosa remaining unmolested without endotracheal lesion or cartilage dislodgement into the trachea. The operation was carried out uneventfully and the fracture was treated conservatively. After extubation, the patient recovered smoothly and had no symptoms suggestive of tracheal narrowing or hoarseness of voice. Neck computed tomography and fiberoptic bronchoscopy were performed postoperatively, both of which showed normal tracheal ring alignment without evidence of edema or hematoma. The patient was discharged 3 days after operation. At the 3-month follow-up, she displayed good airway function and phonation. After review of her clinical history, we speculated that the tracheal ring fracture was caused by forced external compression of the tracheal cartilage during endotracheal intubation.
Keywords
fractures, cartilage; intubation, intratracheal; larynx, external manipulation; trachea;
1. Introduction
External laryngeal manipulation (ELM) is a simple maneuver to improve the laryngeal view during laryngoscopy to facilitate endotracheal intubation. Applying optimal ELM by an assistant is suggested and often practiced in all cases of difficult laryngoscopy.1−3
Tracheal injuries after endotracheal intubation are infrequent but may cause lethal events.4−6 We report a case of tracheal ring fracture associated with ELM for assisting endotracheal intubation in a female patient with difficult laryngoscopy. This is a rare complication of endotracheal intubation due to ELM.
2. Case Report
A 64-year-old woman (height, 162 cm; weight, 57 kg) presented with progressively enlarging neck mass for 2 years and required lobar thyroidectomy under the impression of huge multinodular goiter. She had undergone hysterectomy smoothly 13 years previously but was ignorant of whether or not she had met with difficult intubation in the last operation. The patient had no prior trauma of her neck. Her past medical history was otherwise unremarkable.
Preoperative investigations including electrocardiogram, complete blood count, renal function, liver enzymes, and coagulation profiles were all within normal limits. Neck examination showed a huge nodular mass mainly encroaching on the left side of the neck, which was movable upon swallowing. The nodular mass was firm in consistency and lay under the normal overlying skin. Fine needle biopsy showed multinodular goiter. Airway evaluation revealed a partly visualized uvula during tongue protrusion (Mallampati class II), and the range of neck motion was good. Chest X-ray showed a mass encroaching on the paratracheal area and the trachea displaced to the right.
The patient was scheduled to undergo thyroidectomy under general anesthesia with endotracheal intubation. Anesthesia was induced with intravenous fentanyl 150 μg, thiamylal 300 mg, and cisatracurium 8 mg. Endotracheal intubation was initially carried out by a senior resident with considerable experience under direct laryngoscopy with a No. 3 Macintosh blade. A difficult laryngoscopy with a CormackLehane grade 3 view of the larynx was noted. After two failed attempts, tracheal intubation was taken over by a staff anesthesiologist with the senior resident performing ELM to help bring the glottic opening into view. The senior resident stood by the patient’s left side and used his left hand to apply ELM. The larynx was pressed forcefully at the lower border of the goiter. The pressure was directed posteriorly and cephalad. A cuffed endotracheal tube with an internal diameter of 7.0 mm was passed through the trachea without resistance, and anesthesia was then maintained with 6% desflurane in a mixture of 50% air and 50% oxygen.
On skin incision and tissue exposure, the surgeon noticed a tracheal ring fracture. The fractured site was on the right side of the second tracheal cartilage. The left fractured stump protruded outward and the normal ring shape of the tracheal cartilage was lost. Fiberoptic bronchoscopy performed immediately showed intact tracheal mucosa without endotracheal lesion or cartilage dislodgement into the trachea. The surgeon proceeded to complete the operation. The left thyroid lobe, which measured 5 × 5 × 4 cm, was excised.
Vital signs remained stable throughout the procedure that lasted 1 hour. At the end of the operation, residual neuromuscular blockade was reversed by anticholinesterase (neostigmine) and the patient regained spontaneous respiration. We performed another fiberoptic bronchoscopy before extubation. As the endotracheal tube was withdrawn, we passed the bronchoscope into the trachea to look for any possible injury. Bronchoscopic examination showed a normal tracheobronchial tree and larynx with intact mucosa. There was no obvious trauma, edema or hematoma. No dislodged tracheal cartilage was found. Consequently, the patient was managed conservatively with vigilant monitoring of her respiration.
The patient recovered smoothly and was free from respiratory distress. There were no symptoms suggestive of tracheal narrowing and her voice was unaffected. Neck computed tomography taken on the same day showed normal alignment of the tracheal rings. Fiberoptic bronchoscopy performed the next day showed no endotracheal lesion. She was discharged 3 days after the operation. At the 3-month follow-up, her airway and phonation were good.
3. Discussion
ELM is helpful to improve the laryngoscopic view for tracheal intubation. Routine use of external laryngeal compression may reduce the 9% common occurrence rate of grade 3 view to a rate ranging from 1.3% to 5.4%.1−3 Consequently, use of ELM is suggested in all cases of difficult laryngoscopy.1 The site for application of ELM is the area overlying the thyroid cartilage (occasionally the cricoid cartilage but rarely the hyoid cartilage). ELM improves laryngeal view by pushing the larynx downward into the line of vision so that the epiglottis is more effectively elevated and the anterior tilt of the larynx is decreased. Optimal external laryngeal compression is usually applied backward, upward, and rightward on the thyroid cartilage. Since the location and direction for ELM is variable from patient to patient, it is best for the operator to determine the manipulation and advise the assistant accordingly.1,2
In our patient, ELM was used to facilitate endotracheal intubation in the circumstance of a bad laryngoscopy that offered only a Cormack-Lehane grade 3 view. Because of the huge goiter, the usual location for ELM was not helpful. Instead of choosing the thyroid cartilage, cricoid cartilage or hyoid cartilage, we had to apply ELM just below the rim of the cricoid cartilage, which corresponded to the lower border of the goiter. Direct forced compression over the second tracheal ring probably resulted in its fracture.
Trauma to oral tissue is a common complication following endotracheal intubation and laryngoscopy.7 However, the occurrence of tracheal injuries is rarely encountered after endotracheal intubation. Transmural trauma of the membranous part of the tracheobronchial tree may cause symptoms of respiratory distress, tracheobronchial hemorrhage, subcutaneous emphysema, difficult manual ventilation, pneumomediastinum or pneumothorax.4−6 On the other hand, iatrogenic trauma of the cartilaginous part of the upper airway is seldom reported. Heath et al described fracture of the cricoid cartilage in a patient with a previous laryngeal injury who underwent emergent intubation under Sellick’s maneuver.8 The fracture was discovered when the patient developed stridor and hypoxia on extubation.
Tracheal ring fracture is a rare complication of ELM for endotracheal intubation. Isolated fracture of tracheal ring has been reported after percutaneous dilatational tracheostomy,9−11 with an incidence of 8.9% using the Blue Rhino technique and 0.4% using the Ciaglia technique.11 Regardless of which method is used, all percutaneous tracheostomies share a similar working principle, that is, the trachea has to be punctured, dilated and cannulated. These procedures increase the risk of tracheal ring fracture or destruction.12
The patient had a progressively enlarging neck mass for 2 years, which compressed and deviated the trachea. Previous reports advocated that some anatomic or other factors might predispose to rupture of membranous parts of the trachea after endotracheal intubation. These factors include weakness of the membranous trachea, large mediastinal masses causing distortion of the trachea, steroid therapy, chronic obstructive pulmonary disease, and tracheomalacia.5 Therefore, the huge goiter of our patient could have weakened the tracheal cartilage and a stronger force was needed to push it downward, which might have contributed to the tracheal injury in our patient.
Tracheal injuries may be life-threatening and require early recognition and protection of the airway. Dislodgement of tracheal cartilage into the trachea lumen has been reported after percutaneous dilatational tracheostomy.9,10 Airway obstruction and bleeding or edema of the trachea could result from dislodged fragments of tracheal cartilage falling into the trachea. Although tracheal ring fracture remains an uncommon injury after ELM, we must look for possible injury when patients show symptoms suggestive of acute airway obstruction after difficult laryngoscopy with ELM.
Our patient had no symptoms of tracheal injury, such as a change in voice quality, pain, dysphagia, odynophagia, hemoptysis, stridor or dyspnea. We discovered the fracture only because the fractured site was exposed in the operating field. The diagnosis of tracheal ring fracture would have been missed if the operation did not involve the neck region.
In conclusion, we have reported the rare complication of tracheal ring fracture that occurred as a result of endotracheal intubation with ELM. We emphasize the importance of early diagnosis of possible tracheal cartilage injury in patients with difficult laryngoscopy aided by ELM. Tracheal injury is a potentially lethal event that requires early recognition and protection of the airway. Symptoms of acute airway obstruction after difficult laryngoscopy with ELM must be carefully evaluated to rule out the possibility of tracheal injury.