2018 Section 6 - Laryngology, Voice Disorders, and Bronchoesophalogy

L ARYNGEAL EXAMINATION IN THYROID AND PARATHYROID SURGERY

patient tolerance, and patient apprehension and discomfort represent the greatest challenges. 20,22 Caution should be observed in patients with a history of nasal obstruction and pathology, epistaxis, poorly controlled hypertension, and allergy to topical anesthetics or other adjunctive medications. 22 Nonetheless, flexible fiber-optic nasal lar- yngoscopy represents an important technique in the evalu- ation of patients undergoing thyroid surgery, allowing for early opportunities in the diagnosis of tumor-related laryngeal nerve dysfunction, assessment of airway inva- sion, and early diagnosis and follow-up of postoperative laryngeal nerve dysfunction. Finally, although fiber-optic nasal endoscopy is a brief examination modality in rou- tine cases, it can be prolonged as long as is necessary depending on the pathology observed and is tolerated well by a vast majority of patients. Although use of ultrasound technol- ogy for destruction of laryngeal lesions began to be described in the early 1960s, 23 diagnostic use of ultra- sound to define normal and abnormal laryngeal anatomy lagged behind by about a decade. Techniques, anatomy, potential uses, and pitfalls for laryngeal ultrasound have been continuously described since then. Recently, there has been growing interest in the use of ultrasound specifi- cally for evaluation of the vocal cords and both endoso- nographic and transcutaneous methods have been described. Uses for transcutaneous laryngeal ultrasound include but are not limited to evaluation of vocal cord motion, vocal cord lesions, invasive malignancies external to the thyroid cartilage, nonsurgical etiologies of vocal cord paralysis or dysphonia, immediate perioperative investigation of stridor, and prediction of postextubation stridor secondary to airway edema. 24,25 The learning Laryngeal ultrasound.

FIGURE 1. Transverse view during laryngeal ultrasound per- formed using a 10 MHz linear transducer. Portions of the true cords (TC), false cords (FC), and arytenoids (A) are able to be visualized in the same plane in this image. All 3 structures will not be visualized in the same plane in all patients.

require adjunctive testing in the form of cricothyroid mus- cle electromyography (EMG) to secure accurate diagno- sis. 21 It may be indicated by diminished laryngeal elevation, and decreased ipsilateral longitudinal tension on the vocal cords and hemilarynx, which, in severe cases, creates a picture of laryngeal rotation to the side of involved nerve dysfunction. Fiber-optic nasal endoscopy is well-tolerated and can be achieved successfully in the adult population in nearly 100% of patients. The examination is possible when toler- ance of transoral mirror or telescopic examinations may not be. The greatest limitation of the examination is

FIGURE 2. (A) Normal vocal cord motion with full and symmetrical abduction bilaterally is shown during inspiration. (B) Complete and symmetrical adduction bilat- erally is shown during a Valsalva maneuver. TC, true cord.

HEAD & NECK—DOI 10.1002/HED JUNE 2016

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