How is injury to the superior laryngeal nerve due to thyroid surgery diagnosed and managed?

Updated: Feb 27, 2020
  • Author: Pramod K Sharma, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The external branch of the superior laryngeal nerve (SLN) is probably the nerve most commonly injured in thyroid surgery, with an injury rate estimated at 0-25%. Trauma to the nerve results in an inability to lengthen a vocal fold and, thus, inability to create a high-pitched sound; this may be career-threatening for singers or others who rely on their voice for their profession. Speech therapy is the only treatment. Presentation and diagnosis are as follows:

  • Most patients do not notice any change in their voice

  • Occasional patients present with mild hoarseness or decreased vocal stamina

  • On laryngoscopy, posterior glottic rotation toward the paretic side and bowing of the vocal fold on the weak side may be noted; the affected vocal fold may be lower than the normal one

  • Videostroboscopy demonstrates an asymmetric, mucosal traveling wave

  • Laryngeal EMG demonstrates cricothyroid muscle denervation

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