Effect of Topical Anesthesia on the Phonation Process During High-Speed Digital Imaging Laryngoscopy in Patients With Laryngopharyngeal Reflux

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 Study

The goal of this clinical trial is to learn if topical anesthesia (lidocaine spray) affects the phonation process during High-Speed Digital Imaging (HSDI) laryngoscopy in adults with laryngopharyngeal reflux (LPR). The main questions it aims to answer are:

Does topical anesthesia change phonation process parameters (such as mucosal wave amplitude, glottal closure pattern, phase symmetry, and periodicity) as assessed on the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) form? Does topical anesthesia change the type of glottal insufficiency observed during phonation?

Researchers will compare HSDI recordings performed with topical anesthesia (lidocaine spray) to recordings performed with placebo (physiological saline) to see if topical anesthesia alters phonation process findings.

Participants will:

Undergo HSDI laryngoscopy recording on two consecutive days, once with topical anesthesia and once with placebo, in a randomized, double-blind order Have a detailed medical history taken and complete the Reflux Symptom Index (RSI) questionnaire Undergo fiberendoscopic examination for determination of the Reflux Finding Score (RFS) Return for a follow-up examination within three months, during which they will continue proton pump inhibitor therapy and hygienic-dietary measures

Study Overview

• Status: Completed
• Conditions: Laryngo-pharyngeal Reflux
• Intervention / Treatment: Drug: Lidocaine 10% Spray; Drug: Placebo

Detailed Description

Standard clinical practice for rigid transoral laryngoscopy, including High-Speed Digital Imaging (HSDI), includes the elective use of topical anesthesia of the oral cavity and oropharynx; however, clearly defined recommendations and indications for its use are lacking, and its potential effect on the phonation process has not been unequivocally established. Upon application to the oral cavity and oropharynx, anesthetic may drain into the larynx and desensitize the mucosa, potentially affecting sensorimotor aspects of laryngeal function. Existing studies on the effect of topical anesthesia on phonation during laryngoscopy are limited and report contradictory findings.

This prospective, randomized, double-blind, placebo-controlled crossover study assigned each participant a unique number via random number generator, determining the order of recording modalities (even numbers recorded first with topical anesthesia, odd numbers first without). Once assigned, the order could not be changed. Randomization and testing order were concealed from the examiner performing the HSDI recording.

Topical anesthesia (lidocaine spray, 100 mg/ml, 0.1 ml per actuation) or physiological saline (placebo) was applied by a junior physician, blinded to the substance used, to the base of the tongue, posterior pharyngeal wall, and soft palate (one actuation per site). HSDI recording was performed 5 minutes after application. Each participant underwent recording in both modalities on two consecutive days, a period considered sufficiently short to avoid confounding phonotraumatic, hormonal, or health-related changes.

HSDI recordings were performed by an experienced otorhinolaryngologist and phoniatrician (>5 years of experience) using a rigid 90° endoscope (Wolf 5562 HRES ENDOCAM with Wolf Auto LP 5132 Hlight light source, Richard Wolf GmbH, Knittlingen, Germany). Participants were seated upright with the tongue held protruded; the endoscope was passed along the midline of the tongue to visualize the full length of the vocal folds. Participants phonated the vowel /a/ dynamically and frequentially, and a 2-second HSDI recording was captured. Recordings were reviewed for quality (minimum 1,000 clear, focused, consecutive images of the full vocal fold length during the steady phonation phase); inadequate recordings were repeated. Fundamental frequency and phonation intensity were recorded via a microphone mounted on the endoscope with software processing. Maximum Phonation Time was determined from three stopwatch-timed measurements of sustained /a/ phonation, taken immediately before and after HSDI recording.

Each HSDI recording was independently assessed by two experienced otorhinolaryngologists/phoniatricians (>5 years of experience) using visual-perceptual analysis. Discrepancies in parameter scoring were resolved through joint re-analysis and discussion until consensus was reached before proceeding to the next recording. Assessment was standardized using the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) form and the European Laryngological Society (ELS) form for glottal closure pattern classification, along with a modified classification of glottal insufficiency. The Reflux Finding Score was re-determined from recordings according to the Belafsky et al. classification.

Participants underwent a follow-up examination within three months of study participation, during which the Reflux Finding Score (via fiberendoscopy) and Reflux Symptom Index (via questionnaire) were re-assessed while participants continued regular proton pump inhibitor therapy and hygienic-dietary measures; participants with persistent pathological findings were excluded from final analysis.

Statistical analysis included the Kolmogorov-Smirnov test for normality of distribution. Normally distributed variables were described using means and standard deviations; non-normally distributed variables were described using medians and ranges. Differences between recordings with and without topical anesthesia were tested using the paired t-test (parametric) or Wilcoxon signed-rank test (non-parametric), as appropriate. Spearman correlation and regression analysis were used to explore associations between anatomical structures and measured characteristics. A p-value <0.05 was considered statistically significant.

• Study Type: Interventional
• Enrollment (Actual): 70
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Croatia
  • Zagreb, Croatia, 10000
    • University Hospital Centre Zagreb (KBC Zagreb), Department of ORL Head and Neck Surgery

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Newly diagnosed laryngopharyngeal reflux (LPR), defined as Reflux Symptom Index (RSI) >13 and Reflux Finding Score (RFS) >7 Age 18-45 years No prior HSDI recording Ability to tolerate HSDI examination without topical anesthesia

Exclusion Criteria:

• Known allergy to lidocaine and/or other allergens Acute respiratory infection within the preceding month Current smokers or regular alcohol consumers Chronic rhinosinusitis Prior surgery and/or radiotherapy of the larynx, neck, or thyroid gland Inability to visualize the full length of the vocal folds during the 2-second HSDI recording for anatomical reasons

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Anesthesia-First Sequence (A→B); Participants received topical anesthesia (lidocaine spray, 100 mg/ml) applied to the base of the tongue, posterior pharyngeal wall, and soft palate on Day 1, followed by HSDI laryngoscopy 5 minutes later. On Day 2, the same participants received placebo (physiological saline), identically applied, followed by HSDI laryngoscopy. Order was determined by randomization.	Drug: Lidocaine 10% Spray; Lidocaine spray, 100 mg/ml, administered topically as one actuation (0.1 ml) each to the base of the tongue, posterior pharyngeal wall, and soft palate, approximately 5 minutes prior to HSDI laryngoscopy. Administered once per participant, on one of the two study days according to randomized sequence assignment.; Other Names: Xylocaine spray; Drug: Placebo; Physiological saline (0.9% NaCl) spray, administered topically as one actuation (0.1 ml) each to the base of the tongue, posterior pharyngeal wall, and soft palate, approximately 5 minutes prior to HSDI laryngoscopy. Administered once per participant, on one of the two study days according to randomized sequence assignment, identical in application technique to the lidocaine intervention.; Other Names: Normal saline spray; 0.9% NaCl spray
Placebo Comparator: Placebo-First Sequence (B→A); Participants received placebo (physiological saline) applied to the base of the tongue, posterior pharyngeal wall, and soft palate on Day 1, followed by HSDI laryngoscopy 5 minutes later. On Day 2, the same participants received topical anesthesia (lidocaine spray, 100 mg/ml), identically applied, followed by HSDI laryngoscopy. Order was determined by randomization.	Drug: Lidocaine 10% Spray; Lidocaine spray, 100 mg/ml, administered topically as one actuation (0.1 ml) each to the base of the tongue, posterior pharyngeal wall, and soft palate, approximately 5 minutes prior to HSDI laryngoscopy. Administered once per participant, on one of the two study days according to randomized sequence assignment.; Other Names: Xylocaine spray; Drug: Placebo; Physiological saline (0.9% NaCl) spray, administered topically as one actuation (0.1 ml) each to the base of the tongue, posterior pharyngeal wall, and soft palate, approximately 5 minutes prior to HSDI laryngoscopy. Administered once per participant, on one of the two study days according to randomized sequence assignment, identical in application technique to the lidocaine intervention.; Other Names: Normal saline spray; 0.9% NaCl spray

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Phonation Process Parameters Assessed by the Voice-Vibratory Assessment with Laryngeal Imaging (VALI) Form	Parameters assessed by visual-perceptual analysis of HSDI recordings using the VALI form: glottal sufficiency pattern, mucosal wave amplitude, free edge amplitude, vertical level of the vocal folds, non-vibrating segment of the vocal fold, supraglottic structure activation, free edge contour, open-to-closed phase ratio of the glottal cycle, phase symmetry of the vocal folds, periodicity, and axis shift of the vocal folds. Each recording was independently scored by two blinded raters, with discrepancies resolved by consensus.	Assessed once per recording session; each participant recorded on 2 consecutive days (with and without topical anesthesia)
Change in Glottal Closure Pattern (European Laryngological Society Classification)	Glottal closure pattern during the initial phase of the glottal cycle, classified according to the European Laryngological Society (ELS) form (e.g., concave, convex, straight, complex), assessed by visual-perceptual analysis of HSDI recordings.	Assessed once per recording session; each participant recorded on 2 consecutive days (with and without topical anesthesia)
Change in Type of Glottal Insufficiency (European Laryngological Society Classification)	Type of glottal insufficiency during phonation, classified according to a modified European Laryngological Society (ELS) classification (e.g., complete glottal closure, incomplete closure in the cartilaginous part of the glottis), assessed by visual-perceptual analysis of HSDI recordings.	Assessed once per recording session; each participant recorded on 2 consecutive days (with and without topical anesthesia)
Change in Acoustic Voice Parameters (Fundamental Frequency and Phonation Intensity)	Fundamental frequency (F0, Hz) and phonation intensity (dB) during phonation of the sustained vowel /a/, recorded via a microphone mounted on the endoscope with software processing.	Assessed once per recording session; each participant recorded on 2 consecutive days (with and without topical anesthesia)
Change in Maximum Phonation Time (MPT)	Maximum duration (seconds) of sustained, dynamically stationary phonation of the vowel /a/ following maximal inhalation, determined as the longest of three stopwatch-timed trials performed immediately before and after HSDI recording.	Assessed immediately before and after each HSDI recording session; each participant recorded on 2 consecutive days (with and without topical anesthesia)

Collaborators and Investigators

• Sponsor: Mario Bilić
• Investigators: Principal Investigator: Mario Bilić, prof. dr. sc. dr. med., Department of ORL Head and Neck Surgery, University Hospital Centre Zagreb, Croatia

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2019
• Primary Completion (Actual): January 5, 2021
• Study Completion (Actual): December 5, 2021

Study Registration Dates

• First Submitted: July 6, 2026
• First Submitted That Met QC Criteria: July 6, 2026
• First Posted (Actual): July 10, 2026

Study Record Updates

• Last Update Posted (Actual): July 10, 2026
• Last Update Submitted That Met QC Criteria: July 6, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Lidocaine; Laryngopharyngeal Reflux; Phonation; Topical Anesthesia; High-Speed Digital Imaging
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Digestive System Diseases; Gastrointestinal Diseases; Esophageal Diseases; Laryngeal Diseases; Esophageal Motility Disorders; Deglutition Disorders; Gastroesophageal Reflux; Laryngopharyngeal Reflux; Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Acetanilides; Lidocaine
• Other Study ID Numbers: Class No.8.1-19/31-2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data are not made publicly available due to privacy and confidentiality restrictions related to patient health information. De-identified data underlying the results reported in this publication may be made available by the corresponding author upon reasonable request, subject to institutional and ethics committee approval.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No