J Korean Neurosurg Soc.  2012 Sep;52(3):264-266.

Bilateral Internal Superior Laryngeal Nerve Palsy of Traumatic Cervical Injury Patient Who Presented as Loss of Cough Reflex after Anterior Cervical Discectomy with Fusion

• Shin DU
• Sung JK
• Nam KH
• Cho DC

Abstract

Injury to the bilateral internal branch of superior laryngeal nerve (ibSLN) brings on an impairment of the laryngeal cough reflex that could potentially result in aspiration pneumonia and other respiratory illnesses. We describe a patient with traumatic cervical injury who underwent bilateral ibSLN palsy after anterior cervical discectomy with fusion (ACDF). An 75-year-old man visited with cervical spine fracture and he underwent ACDF through a right side approach. During the post-operative days, he complained of high pitched tone defect, and occasional coughing during meals. With a suspicion of SLN injury and for the work up for the cause of aspiration, we performed several studies. According to the study results, he was diagnosed as right SLN and left ibSLN palsy. We managed him for protecting from silent aspiration. Swallowing study was repeated and no evidence of aspiration was found. The patient was discharged with incomplete recovery of a high pitched tone and improved state of neurologic status. The SLN is an important structure; therefore, spine surgeons need to be concerned and be cautious about SLN injury during high cervical neck dissection, especially around the level of C3-C4 and a suspicious condition of a contralateral nerve injury.

Keyword

Superior laryngeal nerve; Cervical discectomy; Cough reflex

MeSH Terms

Aged
Cough
Deglutition
Diskectomy
Humans
Laryngeal Nerves
Meals
Neck Dissection
Paralysis
Pneumonia, Aspiration
Reflex
Spine

Figure

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  Fig. 1 Imaging of preoperative evaluation, including plain X-ray, computed tomography (CT) scan, magnetic resonance imaging (MRI), and CT angiogram. A : Simple lateral cervical plain X-ray shows subluxation of C3-C4. B : Preoperative sagittal CT scan shows a left lateral mass fracture of the C3 level. C : T2 weighted image of MRI reveals disrupted disc material on C3-C4 with signal change of the cervical cord. D : CT angiogram indicates compromised left vertebral artery flow.

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  Fig. 2 Post-operative plain X-ray imaging shows anterior and posterior (right unilateral) fusion using a cage with a plate and lateral mass screws in lateral (A) and AP (B) view images.

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  Fig. 3 Initial video fluoroscopic swallowing study shows aspiration of thin and thick fluid. Arrows indicates aspiration materials under vocal cords.

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  Fig. 4 Laryngeal eletromyography reveals that there is no motor unit action potential (MUAP) in the right cricothyroid muscle. And, normal MUAPs were identified in the left cricothyroid muscle and both thyroarytenoid muscles.

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  Fig. 5 Video-laryngoscopy shows slight bowing of the right vocal cord (white arrow). E : epiglottis, VF : vestibular fold, VC : vocal cord, AC : arytenoid cartilage.

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