Traumatic recurrent laryngeal nerve injury

A twenty-four year-old male presented after a stab wound to zone II of the right side of his neck.  His airway was intact, and he had bilateral breath sounds. He was hemodynamically stable without active bleeding or an expanding hematoma. His voice was hoarse since the incident, but he had no stridor or difficulty breathing. A CT angiogram was obtained to rule out vascular injury, and asymmetry of the right vocal cord compared to the left was evident.

The patient had blood in his esophagus on EGD and then developed an expanding neck hematoma. He was taken emergently to the operating room for exploration. An incision anterior to the sternocleidomastoid muscle was made. A hematoma was encountered, ligation of visible vessels in the muscle was performed. An injury to the lateral wall of the esophagus was identified at the level just inferior to the thyroid cartilage. The recurrent laryngeal nerve was not identified. The esophageal injury was repaired and external drainage performed.

Following extubation, the patient underwent flexible fiberoptic laryngoscopy. The left true vocal fold had normal mobility. The right true vocal fold was paretic, immobile, and in the paramedian position. There was a 1-2 mm posterior glottic gap present on phonation. The airway was widely patent.

His swallow studies were negative for leak. For one week, the patient was fed via a nasogastric tube that was placed intraoperatively. A video swallow test was positive for aspiration of thin liquids, but the patient was cleared for a thick liquid diet. His nasogastric tube was removed, and the patient was discharged home after about 9 days in the hospital.

The recurrent laryngeal nerve provides motor function to most of the intrinsic laryngeal muscles. Unilateral injury results in paralysis of the ipsilateral vocal cord, which changes the quality of the voice, but rarely compromises the airway. The cord may remain in a paramedian position or be adducted toward the midline. Bilateral injury may severely compromise airflow, necessitating tracheostomy.

The recurrent laryngeal nerve courses around the subclavian artery on the right and the aorta near the ductus arteriosus on the left. The nerve then ascends in the tracheoesophageal groove to the thyroid gland. In <0.5% of patients, and almost exclusively on the right, a nonrecurrent nerve exists, usually in association with vascular anomalies of the aortic arch. The nerve will approach the cricothyroid membrane obliquely from above.

Vocal cord paralysis is a rare event. Iatrogenic injury to the recurrent laryngeal nerve is the most common cause, usually during thyroid surgery. Traumatic injury is much less common. Temporary recurrent laryngeal nerve injuries are more common than permanent injuries. Patients should be followed for 6-9 months to see if vocal cord function returns.

Cases of traumatic recurrent laryngeal nerve injury are described in the literature. Recurrent laryngeal nerve injury is associated with traumatic rupture of the thoracic aorta and great vessels. A mediastinal traction injury after a fall is described, resulting in a pneumothorax and left recurrent laryngeal nerve injury. Blunt cervical trauma and strangulation are associated with disruption of the laryngo-tracheal junction, which can be associated with both bilateral and unilateral recurrent nerve injuries. Recurrent laryngeal nerve injury has been associated with penetrating injuries as well, such as a stab wound to the neck and tracheal injury. As far as recovery, all of the patients had restoration of airway patency and recovery of voice. Most patients were observed, but some had surgical reanastomosis of the nerve. Other treatments include those focusing on improvement of the voice, expansion of the glottis, and melioration of dyspnea.

References
1.  Deziel et al. Rush Review of Surgery, third edition. 2000. Chapter 21: Thyroid.
2.  Yao et al. Laryngeal nerve anatomy. Emedicine.medscape.com.
3.  Baguley CJ, Sibal AK, Alison PM. Repair of injuries to the thoracic aorta and great vessels: Auckland, New Zealand 1995-2004. ANZ J Surg. 2005; 75:383-7.
4.  Ng MK, Barling A, Chan S. Mediastinal traction injury to the recurrent laryngeal nerve: An unusual cause for a hoarse voice. Am J Case Rep. 2012; 13:36-7.
5.  Couraud L, Velly JF, Martigne C, N’Diaye M. Post traumatic disruption of the laryngo-tracheal junction. Eur J Cardiothorac Surg. 1989; 3:441-4.
6.  Veit JA, Metternich F. Management of traumatic tracheal injuries: presentation of a rare case and review of the literature. Laryngorhinootologie. 2008; 87:270-3.

from: Lindsay Petersen, MD, PGY5