Thyroid Cartilage Fracture Following Endotracheal Intubation

Adverse events resulting from endotracheal intubation have been well documented throughout history. Known complications include dental trauma, edema, lacerations, vocal cord paralysis, tracheal stenosis, fistulas, esophageal or bronchial intubation, and tracheal perforation [1]. However, involvement of the laryngeal cartilages is highly unlikely, as fracture of the laryngeal cartilages typically requires a substantial impact force [2]. To our knowledge, thyroid cartilage fracture (TCF) following endotracheal intubation has not been reported. Here, we present a unique case of TCF and subglottic perforation following attempted endotracheal intubation, discussing the associated risk factors and offering recommendations for preventive measures. A 41-year-old female with a history of obstructive sleep apnea and body mass index (BMI) of 60 was seen in the emergency department for an episode of acute bronchitis. After chest x-ray suspicious for pulmonary embolism, chest computed tomography angiogram demonstrated a massively enlarged left with substernal extension greater than right thyroid gland with tracheal deviation, and a separate mediastinal mass of similar density measuring approximately 9.2 × 7.6 cm (Figure 1). The patient was referred for multidisciplinary management of her massive neck and mediastinal goiters with cardiothoracic surgery. On the day of the procedure, the patient was positioned supine on the operating table and intubation was attempted using an awake flexible fiberoptic approach by the anesthesia team, but this was unsuccessful. After multiple attempts and after induction with the aid of a short acting paralytic succinylcholine, the patient was intubated using a videolaryngoscope (Glidescope hyperangulated S3 blade, Verathon Inc.) along with a GlideRite rigid stylet, although there was difficulty passing the endotracheal tube (ETT) beyond the subglottis. A size 6 ETT equipped with electromyography (EMG) electrodes was used. Unfortunately, it was difficult to ventilate the patient, and the EMG electrodes did not function properly when connected to the EMG monitor. An attempt was made to exchange the tube using a bougie ETT introducer 15 Fr × 70 cm, but the new tube could not be passed. Upon inspection, it was noted that the ETT had buckled in the oropharynx. The anesthesia team agreed to have our team attempt to intubate the patient at this point, and the supervising surgeon successfully intubated with a BriteProSolo Miller 2 blade to visualize the glottis and then guide a flexible intubation scope to visualize the tracheal lumen, over which a regular size 6 ETT was passed. Once the patient was positioned for surgery, mild subcutaneous emphysema of the anterior neck and upper chest was noted. An inferior transverse incision was made, and only after resection of the overlying massive left thyroid and pyramidal lobes was a vertical fracture of the thyroid cartilage able to be identified just left of midline. The thyroidectomy approach isolated the recurrent laryngeal nerves followed by complete transection of the medial attachments of the thyroid gland to the trachea to facilitate delivery of the massive substernal goiter [2]. Upon completion of total thyroidectomy, the injury could be fully examined. A left subglottic soft tissue injury was noted, with the ETT visible through the small opening of the lateral cricothyroid membrane just deep and inferior to the TCF. A 6-0 prolene suture was used to appose the mucosal tear, and interrupted 4-0 prolene sutures were used to reduce the TCF. The cricothyroid membrane was repaired with a watertight 4-0 running prolene suture and reinforced with strap muscle, which was sewn over the repair. Copious saline irrigation was performed throughout to minimize bacterial concentration, and flagyl was administered as soon as the communication with the subglottis was noted in addition to preoperative Ancef prophylaxis for sternotomy. Cardiothoracic surgery then performed thoracotomy to remove the large mediastinal goiter. Ultimately, the decision was made to keep the patient intubated, as significant laryngeal trauma was sustained during intubation attempts. The patient was kept intubated after surgery and the cardiothoracic service, the intensive care unit staff, and our service agreed with examination under anesthesia and extubation in the OR, which was done on postoperative day seven. At this time, the patient was noted to have bilateral posterior glottis granulomas. At the three-week postoperative visit, the patient reported improved hoarseness. The incision was well healed, with no areas of dehiscence or crepitus. Flexible laryngoscopy at that time demonstrated bilateral contact ulcers in the posterior glottis, with right greater than left vocal cord motion. Laryngeal injuries are more frequently the result of blunt force rather than penetrating trauma, which most often consists of motor vehicle collisions, assault, or sports injuries. This is almost always the result of an external force, and external injuries resulting in laryngeal fractures are well documented. An experimental trial by Lee [3] tested the effect of blunt trauma to the larynx by dropping 2 kg of weight from a height of 100 cm on a series of 100 cadaver larynx specimens. Fracture lines were found to be distributed and concentrated over the middle third of the anterior thyroid cartilage and cricoid arch. There is no such clear documentation of mechanisms of TCF resulting from an internal force, as it almost never occurs. Raven et al. [4] analyzed a series of 50 deaths in the setting of resuscitative intubation, and none were found to have TCF. Analyzing the associated risk factors that contributed to the TCF in this patient along with the timing of injury is crucial in understanding this severe complication of endotracheal intubation and preventing it in the future. Contributing factors included tracheal deviation both to the right and posteriorly, long-standing morbid obesity, difficult airway exposure, the use of a rigid stylet, and aggressive intubation with multiple attempts and excessive force. We speculate that the patient's morbid obesity and difficult laryngeal exposure resulted in excessive anterior force applied with the laryngoscope. Additionally, the displacement of the trachea to the right and posteriorly is likely to have obstructed the passage of the stylet, which is consistent with the location of the immediate subglottic perforation at the left anterior location. Taking this into consideration, the TCF and perforation are most likely to have occurred before the patient was turned over to our service. According to the 2022 American Society of Anesthesiologists Practice Guidelines for Management of the Difficult Airway, obesity and tracheal deviation are independent risk factors, predicting the presence of a difficult airway [5]. In our case, the patient was prepared as a difficult airway because of obesity with tracheal deviation. When intubation failed, increased force and repeated attempts were made before altering the plan. Thorough preoperative review of the patient's imaging studies and preparation of alternative intubation plans with anesthesiology may help to prevent the type of injuries described in this case. Excessive force should always be avoided, and in the setting of a significantly deviated trachea, it may be prudent to also avoid rigid equipment and instead opt for softer and more pliable alternatives. We present a case of TCF due to endotracheal intubation in a patient with massive goiter in the neck and separately in the mediastinum, morbid obesity, and pronounced tracheal deviation in multiple planes, who required multiple intubation attempts. A thorough preoperative assessment of patient anatomy, along with a tailored airway management plan developed in collaboration with the anesthesiologist, is crucial to minimizing the risk of such complications. Informed consent for publication of this manuscript was obtained from the patient. The authors declare no conflicts of interest. The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.