2018 Section 6 - Laryngology, Voice Disorders, and Bronchoesophalogy

L ARYNGEAL EXAMINATION IN THYROID AND PARATHYROID SURGERY

Laryngeal examination technique. Flexible transnasal laryn- goscopy is the optimal method for laryngeal examination on the basis of widespread availability, patient tolerance, and assessment of both RLN and EBSLN function. Mirror examination of the larynx can adequately docu- ment vocal fold movement abnormalities and is a useful tool in settings where transnasal laryngoscopy is unavailable. Laryngeal ultrasound may be useful for documenting gross vocal fold movement abnormalities, especially in the pediatric population where use of transnasal laryn- goscopy may be limited. Laryngeal stroboscopy should be considered for people with documented postoperative hoarseness who do not have vocal fold movement abnormalities. There are a number of ways to examine the larynx. Ideally, any given technique would provide information on the function of recurrent and superior laryngeal nerves, intrinsic laryngeal musculature, and mobility of the cri- coarytenoid joint, in addition to laryngeal phonatory func- tion. For widespread usage, any optimal examination technique should be easy to learn and perform, be nonin- vasive and inexpensive. Currently, no single test will pro- vide such a complete laryngeal evaluation and thus choice of optimal technique depends on the goals of test- ing. For most patients undergoing thyroid and parathyroid surgeries, the primary goal is to assess gross motor RLN function. Techniques of laryngeal examination that are best suited to address this primary goal by virtue of their diagnostic utility, accessibility, and ease of use are dis- cussed under primary modalities. It is recognized, how- ever, that select patients may require additional laryngeal examination techniques to adequately assess their laryn- geal function and these techniques are discussed below under secondary modalities. In the initial patient history, symptoms, such as vocal fatigue, pain with speaking, increased effort required for speech, decreased vocal projection, and decreased vocal range, may suggest laryngeal pathology. Age and rapidity of onset plus timing and duration of symptoms should be determined, as should coincident swallowing abnormalities or respiratory difficulties. Subjective patient-rated preoper- ative voice assessment scales, such as the Grade, Rough- ness, Breathiness, Asthenia, and Strain scale and Voice Handicap Index are useful for both clinical and research purposes and can be useful for comparing changes in pre- operative and postoperative vocal symptoms. A swallowing questionnaire may also be useful for symptom documenta- tion, especially given that dysphagia is estimated to occur in over 50% of patients the first week after thyroid surgery and may last for more than 3 months. 17 Indirect mirror laryngoscopy has been largely superseded by flexible nasendoscopic laryngoscopy. Despite this, resource constraints and con- venience maintain indirect mirror laryngoscopy as a valu- able extant examination method. Indirect mirror laryngoscopy can be challenging and the learning curve is not as steep as for flexible laryngoscopy. Proficiency Primary examination modalities Indirect (mirror) laryngoscopy.

requires practice and frequent use during training. Unlike flexible laryngoscopy, swallowing cannot be assessed by mirror examination as it is not possible to swallow with an open mouth. This represents a fundamental disadvant- age of mirror examination compared to the flexible endo- scopic technique. Correct positioning of the patient increases comfort and enhances the examiners view for indirect mirror laryngos- copy. The patient sits back in the chair with legs uncrossed and chin tilted slightly upward. An electric headlight or a head mirror in concert with a flexible lamp associated with the examination chair should be used to reflect light into the oral cavity. The gloved left hand of the examiner pulls the tongue forward using gauze placed between the thumb and index finger. The middle finger retracts the top lip upward. A warmed dental mirror (to avoid breath associated fogging) is placed in the right hand to elevate the uvula and soft palate revealing the lar- ynx. Patients with a strong gag reflex may benefit from the application of a local anesthetic spray to the soft pal- ate before examination. Tonsil and tonsillar fossa struc- tures must not be touched to avoid gagging. Adjunctive measures include gentle pressure of the shaft of the mir- ror against the inside of the cheek, which reduces gagging by a proprioceptive reflex. Stroking of the lip may also be helpful in the same way. Maneuvers to help improve visualization of the glottis include vocalizing “hey,” which elevates an overhanging epiglottis and a jaw thrust that facilitates ventral movement of the tongue. Although it is important to note anatomic abnormalities and lesions, the examiner should assess vocal cord move- ment and adduction when the patient is vocalizing “E.” One trick to assess abduction and adduction of the vocal cords is to imagine a midline glottic imaginary line and then assess the cords medial/inward and lateral/outward motion relative to this midline glottic line. Asymmetry between sides may represent vocal fold paresis or, with complete immobility of 1 fold, paralysis. Erythema of the posterior larynx suggests acid reflux; a common finding. The subtle changes in cord length, thickness, and aryte- noid position associated with injury to the EBSLN are extremely difficult to detect by mirror examination. Rela- tive contraindications for indirect mirror laryngoscopy include a brisk gag reflex, extensive surgery and/or radio- therapy to the mouth with trismus, palatal obturators, or poor mouth opening combined with dental considerations. Caution is also required in patients with acute inflamma- tory swelling of the supraglottis. Below is a comparison of indirect mirror laryngoscopy and the more commonly performed fiber-optic nasal endoscopy (Table 1). Flexible exami- nation of the upper aerodigestive tract is an important adjunct to the assessment and management of patients undergoing thyroid surgery. The examination is easily performed in the office setting and can be performed with or without the use of topical nasal anesthesia, such as lid- ocaine, depending on the patient and individual practi- tioners experience and judgment. The necessity of topical anesthetic is controversial and not universally accepted especially with the availability of small caliber scopes. 18 Once adequately prepared, the patient is examined in the Flexible transnasal fiber-optic laryngoscopy.

HEAD & NECK—DOI 10.1002/HED JUNE 2016

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