Transcutaneous Laryngeal Ultrasonography: Clinical Variables
Transcutaneous laryngeal ultrasound (TLUSG) is a noninvasive and convenient method of assessing the function of both vocal cords (VCs) before and after thyroidectomy. It works by essentially relying on the propagation of ultrasound waves travelling from the anterior neck skin to the VCs and the arytenoids via the ventral window of the thyroid cartilage. As a result, the presence of ossification (i.e., turning from cartilaginous tissue to bone) in the thyroid cartilage is the major determinant of obtaining clear VC visualization by TLUSG. It is now clear that the process of ossification is an inevitable, age-related phenomenon and slowly begins from the posterior part of the thyroid cartilage toward an anteromedial direction. Numerous clinical studies have shown that male patients with advanced age are particularly prone to have a complete ossification of the cartilage rendering VC visualization by TLUSG almost impossible. However, despite this process, one should also realize that since the majority of patients undergoing thyroidectomy are young females, TLUSG should be highly applicable to many thyroid surgeons. With appropriate training, the skills of TLUSG could be quickly learned by surgeons who may or may not routinely perform ultrasound in their practice.
KeywordsUltrasonography Larynx Vocal cord Vocal cord paresis Surgical outcome Recurrent laryngeal nerve injury Thyroidectomy Parathyroid surgery Laryngoscopy
I would like to take this opportunity to thank Dr. KP Wong and Dr. JW Woo for providing some of the wonderful images and videos used in this chapter.
The author declares that he has no competing interests.
BHH Lang was involved in the review of literature, acquisition of data, and drafting and completing the chapter. BHH Lang was also involved in the review of literature and drafting the chapter. BHH Lang conceived the study, participated in the coordination and the acquisition of data and helped to draft the chapter. He read and approved the chapter.
Normal (grade I) movement in both vocal cords (MP4 10,363 kb)
Impaired (grade II) movement in left vocal cord with good compensation (MP4 14,174 kb)
Absent (grade III) movement in left vocal cord (MP4 14,038 kb)
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