The Effect of Topical Anesthesia on the Phonation Process During High-Speed Digital Imaging Laryngoscopy in Patients with Laryngopharyngeal Reflux: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial

Background and Objectives: High-speed digital imaging (HSDI) is the most advanced method of phonation process analysis. Hoarseness is the most common indication for HSDI, and laryngopharyngeal reflux (LPR) is an etiological cofactor of hoarseness in 50% of cases. Clinical practice in HSDI includes the elective use of topical anesthesia (TA), but without defined recommendations and indications for use, and a potential altering effect of TA on the phonation process has not been unequivocally proven. The aim of this prospective, randomized, double-blind, placebo-controlled study was to examine the effect of TA application on the phonation process by analyzing Voice-Vibratory Assessment with Laryngeal Imaging (VALI) form parameters in subjects with LPR. Materials and Methods: A total of 70 volunteer subjects were included in the study; 50 subjects who completed both recording sessions were included in the final analysis. All subjects were recorded in two modalities, with TA application (lidocaine spray 100 mg/mL) and without it, on two consecutive days. Results: By evaluating phonation process parameters according to the VALI form, we determined that TA application during HSDI in subjects with LPR was not associated with statistically significant changes in the evaluated phonation process parameters. Conclusions: TA application during HSDI in subjects with LPR was not associated with significant changes in the analyzed phonation process parameters. Further research is needed to determine the benefit of TA in reducing pain and discomfort during examination, weighed against the risk of potentially life-threatening side effects, in order to individualize the approach to each patient.