The Effect of Topical Anesthesia on Vocal Fold Motion

Topical Anesthesia for Endoscopic Office-based Procedures of the Upper Aerodigestive Tract

OBJECTIVE

Over the last two decades, an increase in office-based procedures under topical anesthesia in laryngology and head and neck oncology has occurred. Adequate anesthesia in the nasal cavity, pharynx, and larynx is essential for successful performance of these procedures. Our goal is to provide an objective summary on the available local anesthetics, methods of application, local secondary effects, efficacy, and complications.

MATERIAL AND METHODS

A descriptive review of literature on topical anesthesia for office-based procedures in laryngology and head and neck oncology was performed.

RESULTS

Lidocaine is the most applied and investigated topical anesthetic. Topical anesthesia results in decreased sensory function without impairing motor function of the pharynx and larynx. For the nasal cavity, cotton pledgets soaked in anesthetic spray and decongestant, or anesthetic gel, are effective. For the pharynx, anesthetic spray is the most frequently used and effective method. For the larynx, applying local anesthesia through a catheter through the working channel of the endoscope or anesthetic injection through the cricothyroid membrane is effective. Studies comparing the most effective application methods for each anatomical site are lacking. Complications of topical lidocaine administration are rare.

CONCLUSIONS

By properly applying topical anesthesia to the upper aerodigestive tract, several surgical procedures in laryngology and head and neck oncology can be performed in the outpatient clinic under topical anesthesia instead of the operating room under general anesthesia. Lidocaine is the most investigated anesthetic, with adequate efficacy and few complications. Studies that determine the most effective application methods are still wanting.

The effect of oral topical anesthesia on the characteristics of voice

OBJECTIVES/HYPOTHESIS

Although oral topical anesthesia is used routinely before rigid laryngeal endoscopy, no study has determined whether oral topical anesthesia changes voice quality. Our goal was to determine the effects of topical anesthesia on voice.

STUDY DESIGN

Prospective cohort study.

METHODS

Adult patients presenting to a laryngology practice who required rigid laryngeal endoscopy as part of the routine clinical visit were eligible for the study. Voices were recorded before and after oral topical benzocaine (14%)/butamben (2%)/tetracaine (2%) (ie, cetacaine) spray. Consensus auditory perceptual evaluation of voice (CAPE-V) protocol was used for the voice recordings and was the primary outcome measure. Recordings were presented randomly to two blinded speech-language pathologists specialized in voice. Secondary outcome measures were fundamental frequency (F0), jitter, shimmer, and noise-to-harmonics ratio (N/H) on sustained /i/ and speaking F0.

RESULTS

One hundred two patients participated in the study. There was no significant difference in CAPE-V measurements before and after topical anesthesia for all six attributes: overall severity (P = 0.145), roughness (P = 0.214), breathiness (P = 0.761), strain (P = 0.053), pitch (P = 0.301), and loudness (P = 0.320). There was no significant difference in jitter (P = 0.315), shimmer (P = 0.942), N/H (P = 0.128), and speaking F0 (P = 0.320). F0 /i/ decreased by a mean of 4.8Hz, which was statistically significant (P = 0.003), but probably not clinically significant.

CONCLUSION

There was no clinically significant voice change after oral topical anesthesia.

A virtual trajectory model predicts differences in vocal fold kinematics in individuals with vocal hyperfunction

A simple, one degree of freedom virtual trajectory model of vocal fold kinematics was developed to investigate whether kinematic features of vocal fold movement confirm increased muscle stiffness. Model simulations verified that increases in stiffness were associated with changes in kinematic parameters, suggesting that increases in gesture rate would affect kinematic features to a lesser degree in vocal hyperfunction patients given the increased levels of muscle tension they typically employ to phonate. This hypothesis was tested experimentally in individuals with muscle tension dysphonia (MTD; N = 10) and vocal nodules (N = 10) relative to controls with healthy normal voice (N = 10) who were examined with trans-nasal endoscopy during a simple vocal fold abductory-adductory task. Kinematic measures in MTD patients were less affected by increased gesture rate, consistent with the hypothesis that these individuals have elevated typical laryngeal muscle tension. Group comparisons of the difference between medium and fast gesture rates (Mann-Whitney, one-tailed) showed statistically significant differences between the control and MTD individuals on the two kinematic features examined (p<0.05). Results in nodules participants were mixed and are discussed independently. The findings support the potential use of vocal fold kinematics as an objective clinical assay of vocal hyperfunction.