2018 Section 6 - Laryngology, Voice Disorders, and Bronchoesophalogy

Chandrasekhar et al

contains afferent fibers that mediate sensation from the vocal folds and below including the upper esophagus and trachea. 30 Neural Injury and Voice Change Early recognition of neural injury, whether temporary or per- manent, may offer opportunities for intervention to improve short- and long-term vocal outcomes, with improved QOL. These issues are covered in detail later in the guideline, but knowing the incidence and prevalence offers additional per- spective on their importance. In a recent review of 27 articles and 25,000 patients, the average incidence of temporary or permanent vocal fold paral- ysis after surgery was 9.8%, with a wide range from 2.3% to 26%, in part related to the timing and method of laryngeal examination. 12 The Scandinavian quality register reported a vocal fold paralysis rate of 4.3% nerves at risk, based on 3660 thyroid operations performed in 2008 in 26 endocrine surgical units from Sweden and Denmark. 37,38 Further, the detection of vocal fold paralysis doubled when patients were submitted to routine laryngeal exam after surgery as compared to laryngos- copy performed only in patients with persistent and severe voice changes. Figure 2. Relationship of recurrent laryngeal nerves (RLN) and superior laryngeal nerves (SLN) to thyroid lobe and tracheoesophageal groove. From Surgery of the Thyroid and Parathyroid Glands Edition 2 , Greg W. Randolph, editor, Elsevier Saunders Philadelphia 2012, reprinted with permission.

Figure 1. Location of the thyroid gland. From Surgery of the Thyroid and Parathyroid Glands Edition 2 , Greg W. Randolph, editor, Elsevier Saunders Philadelphia 2012, reprinted with permission.

Nonrecurrent RLN occurs in less than 1% of cases, is seen during right-sided thyroidectomy when it occurs, and arises directly from the cervical vagus. Given its aberrant course, such a nerve may be more likely injured during thyroidec- tomy 36 ( Figure 4 ). Often, the nonrecurrent RLN occurs in conjunction with an anomalous (retro-esophageal) right sub- clavian artery. If a CT scan is performed during evaluation of thyroid/neck mass and a retro-esophageal subclavian artery is noted, then the surgeon should be on the lookout for a nonre- current laryngeal nerve. It behooves the thyroidectomy sur- geon to be intimately familiar with the course and potential aberrations of these nerves. The neurolaryngology of phonation, swallowing, and res- piration is complex. Cortical representation of the larynx proj- ects to bilateral brainstem nuclei (including nucleus ambiguous), which then projects to the ipsilateral larynx. The RLN carries branchial efferents to the inferior constrictor, cri- copharyngeus, and all laryngeal intrinsic muscles except the cricothyroid muscle. Laryngeal motor fibers within the RLN have a 4 to 1 adductor to abductor ratio. The RLN also

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