The use of topical anesthetic in videostroboscopic examination of the larynx

A Laryngographic and Laryngoscopic Study of Northern Vietnamese Tones

“…The fibrescope was inserted through the nasal cavity into the posterior oral pharynx after one nasal spray of xylocaine 10%. Previous research has found no significant interference of local anaesthesia with laryngeal movement during laryngoscopy [Peppard and Bless, 1991]. The tip of the Laryngeal Production of Vietnamese Tones fibrescope was positioned in the pharynx, above the larynx, high enough to see the entire epiglottis.…”

Double-Blind Study on the Effects of Topical Anesthesia on Laryngeal Secretions

“…Topical anesthesia sprayed into the oro-or nasopharynx is used routinely by physicians for both flexible and rigid endoscopy to diminish the gag reflex and enhance patient comfort. 1,2 As a class, topical anesthetics inhibit the conduction of nerve impulses at the site of application by temporarily blocking the permeation of sodium ions into the nerve cell. 3 Anesthesia not only reduces sensation, but it also inhibits efferent output from the central nervous system thereby reducing motor control.…”

“…5,6 Clinical reports also indicate that topical anesthetics may cause changes in the quantity or quality of laryngeal secretions, specifically by generating secretion "balling" or "pooling" operationalized shortly. 1,7 Each of these reactions can confound interpretation of laryngeal images, which potentially misleads diagnosis.…”

“…Balling is the appearance of discrete accumulations of secretions on the vocal fold surface. 1 Balling is thought to be a possible complication of topical anesthesia in laryngeal endoscopy 1 or a sign of dehydration and thus increased secretion viscosity. The primary concern relative to endoscopy is that secretion balls can be mistaken for mass lesions of the vocal folds.…”

“…1 In that study, 10 adults (five men and five women) with normal larynges were examined before and after the application of Xylocaine (lidocaine 10%) to the oropharynx. No systematic effects of anesthesia were noted on laryngeal secretions.…”