Thyroid Cartilage Fracture: Title and subTitle BreakAn Unusual Presentation

Blunt laryngeal injuries are rare and are not typically seen in isolation; they are usually associated with multiple traumas.¹ Such injuries account for less than 1% of all the cases seen at major trauma centers.^{2 - 4}

As a result of cross-over seatbelts rather than seatbelts that cross the lap only⁵ and other safety measures, high-velocity blunt trauma injuries caused by road traffic accidents are decreasing. Low-velocity blunt trauma injuries are on the rise owing to an increase in sporting injuries. Although women have a greater anatomical predisposition to laryngeal injuries as a result of relatively longer and slimmer necks,⁶ it is usually young males who participate in violent sports, fights, or car racing.⁵ In India (as in many parts of the world), an increasing population with a crowded public transportation system predisposes to accidents and low-velocity neck trauma.

External trauma to the larynx can threaten not only life but also the quality of life. Restoration of the skeletal framework and epithelial lining of the larynx is essential to preserve its vocal and airway protecting function.⁷ In thyroid cartilage fractures, especially at the level of the glottis, patients may present with marked dysphonia or aphonia and a certain degree of laryngeal obstruction.⁸ Some patients, however, may appear deceptively normal. Thus, suspicion and recognition of acute laryngeal injury are imperative.⁷

A 17-year-old male student presented with a shift to the left in the laryngeal prominence (Figure 1) that was unsightly to the patient, first observed 3 to 4 days prior to presentation. There was no history of trauma on initial questioning. On enquiring further the patient gave a history of the possibility of accidental blunt trauma to the neck while traveling in a crowded train 5 days earlier. This was followed by mild pain but no change in the quality of voice or respiratory distress.

On external examination of the neck, there was a shift of the thyroid notch to the left, 3 cm from the midline, which moved normally with deglutition. There was no tenderness on palpation, and the skin overlying this area showed no evidence of trauma. On rigid telelaryngoscopy, there was no evidence of intralaryngeal trauma; however, mild asymmetry of the vocal cords and shift of the anterior commissure was seen. The vocal cords appeared normal and mobile. The rest of the findings from the ear, nose, and throat examination were unremarkable.

A computed tomography scan (Figure 2) of the neck was performed, which showed 2 fracture lines of the left thyroid ala: one was at the junction of the anterior one-third and the posterior two-thirds, and the second was 2 to 3 mm from the midline. The fracture segment was displaced laterally with the loss of normal thyroid prominence. No endolaryngeal edema or intralaryngeal hematoma was seen on imaging results.

After conducting a hematologic, radiologic, and medical workup, anesthesia was administered, and a neck exploration was planned. A thyroidectomy incision was used to approach the thyroid cartilage by dissecting and lateralizing the strap muscles. The displaced fracture segment was visualized with an exposed thyroarytenoid muscle. This fragment was lying perpendicular to the rest of the larynx (Figure 3). It was dissected and removed, and the fractured edges were sutured to one another with 2-0 proline sutures (Figure 4). A suction drain was kept in place, and the wound was closed in 2 layers.

The patient experienced no change in voice postoperatively. A rigid laryngoscopy performed after 7 days showed preoperative tilt of the larynx to the left with healthy laryngeal mucosa and normal vocal cord movements on both sides.

On long-term follow-up, there was no change in the quality of voice and no evidence of laryngeal or subglottic stenosis.

External laryngeal trauma is rarely seen in emergency ear, nose, and throat practices, accounting for only 1 in 30 000 emergency department visits.⁹ Injury to the larynx is uncommon as it is protected posteriorly by a rigid cervical spine, and the inferior projection of the mandible affords protection to a large degree from anterior blows.⁹ This factor is highlighted further among the pediatric age group, in which the larynx is situated higher up in the neck with lesser incidence of trauma.¹⁰

With safer seatbelt technology and traffic rule awareness, the classic dashboard injury is not a culprit as frequently as in the past. However, sport injuries are an increasing cause. In highly populated developing countries such as India, a crowded public transportation system, including local trains or buses, are a common cause of injuries. In trains in which people must stand, holding onto rings from the ceiling, the neck is prone to accidental injury from the elbows of other passengers.

Laryngeal trauma has been classified into penetrating and blunt (further into low and high velocity).⁶ Laryngeal framework fractures may be supraglottic, glottic, and intraglottic. The structure and localization of the larynx is such that injury to the organ is followed by the development of lesions, producing distinctive signs and symptoms.⁷ Clinical features peculiar to supraglottic thyroid fractures include a muffled voice with obstruction and flattening of the neck contour, and if the injury is at the glottis, it may cause cord palsy.⁷ Surprisingly, there was a complete lack of such symptoms in our patient, and he presented only when he noticed an abnormal neck prominence that was cosmetically unacceptable to him.

If the thyroid cartilage is pushed over the spine, then it splays apart, and in the case of a rigid calcified cartilage, it will split down the front or down the thyroid prominence.⁶ No such fractures occur in children and young adults with elastic cartilage.^{6 ,10} Another form of trauma, albeit a rarer one, is a contrecoup injury, where there may be contralateral trauma to the larynx.⁴

Unlike most thyroid fractures where there is frequent displacement of fragments and associated endolaryngeal trauma, the telelaryngoscopy showed a slight tilt with normal endolaryngeal mucosa and vocal folds, and therefore, no dysphonia or dyspnea. An important determinant of the final outcome in terms of both voice quality and airway patency is the timing of surgery.^{11 - 13}

The thyroid cartilage, if fractured, will heal with fibrous union, and, provided it is in a good position, it is just as satisfactory as wiring or stitching it together. At the same time, it is important to note that if there is secondary infection and excessive fibrosis with cicatrisation, deformity and altered laryngeal function such as glottic web and arytenoid joint arthrodesis may occur even after minor injuries.^{5 ,7} Unlike in our case, low-velocity blunt injuries rarely cause a thyroid or cricoid cartilage fracture and thus do not require open exploration,⁵ but in the presence of a thyroid fracture, a midline thyrotomy or an approach through the fracture, if near the midline, is indicated to explore the endolarynx.^{5 ,9} Failure to recognize subtle presentations of these injuries may allow cicatrisation and airway obstruction to manifest days or months after the initial insult.¹⁴

Devascularized pieces of cartilage may become necrotic, giving rise to perichondritis and infection and further fibrosis with endolaryngeal complications. Thus, in this case, to prevent complications and to achieve cosmesis, the fracture fragment was dissected and removed.⁷ Superadded infection was further prevented by using intravenous broad spectrum antibiotics. Satisfactory cosmesis was achieved after the postoperative edema subsided.

In conclusion, systemization of the sequelae of blunt laryngeal trauma is elusive; such injuries must be recognized individually, evaluated, and subjected to appropriate therapy. Although experience in managing laryngeal trauma is limited, because of the rarity of this injury, early identification and management of this condition prevents morbid long-term complications.

Correspondence: Nupur Nerurkar, MS (ENT), D/603 Simla House, Napean Sea Road, Mumbai 400 026. India (nupurkapoor@yahoo.com).

Submitted for Publication: September 9, 2004; accepted November 18, 2004.