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Lidocaine Block of the Recurrent Laryngeal Nerve in Adductor Spasmodic Dysphonia: A Multidimensional Assessment

Authors

  • Marshall E. Smith MD,

    Corresponding author
    1. Division of Otolaryngology–Head and Neck Surgery, The University of Utah School of Medicine, Salt Lake City, Utah, U.S.A.
    • Dr. Marshall E. Smith, Division of Otolaryngology–Head and Neck Surgery, The University of Utah School of Medicine, 3C-120 SOM, 50 N. Medical Drive, Salt Lake City, UT 84132
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  • Nelson Roy PhD,

    1. Department of Communication Sciences and Disorders, The University of Utah, Salt Lake City, Utah, U.S.A.
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  • Cathy Wilson MS

    1. Department of Communication Sciences and Disorders, The University of Utah, Salt Lake City, Utah, U.S.A.
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Abstract

Objectives/Hypothesis: Lidocaine block of the recurrent laryngeal nerve (RLN) has been reported as a procedure for surgical selection of patients with adductor spasmodic dysphonia (ADSD). However, its effects on phonation have not been rigorously assessed in a prospective fashion using strict entry criteria and multiple measures of phonatory function. This investigation assessed the phonatory effects of RLN lidocaine block in ADSD to explore its potential as a diagnostic tool.

Study Design: Single group, pre/postexperimental trial.

Methods: Twenty-one consecutive patients with suspected ADSD underwent unilateral RLN block, causing temporary ipsilateral vocal fold paralysis. Voices were recorded before and during the block. Patients completed self-ratings of overall level of dysphonia severity, vocal effort, and laryngeal tightness. Blinded listeners completed auditory-perceptual ratings, and the frequency of phonatory breaks was acoustically analyzed.

Results: During the block, patients reported significant reductions on overall severity (P = .045), vocal effort (P < .001), and laryngeal tightness (P = .002). Listeners rated the voices during the block as significantly more breathy (P < .001), less strained (P < .001), and less severe (P = .059). Acoustic analysis confirmed significantly fewer phonatory breaks during the block (P < .001). Patient-based ratings of improvement were more consistent than listener ratings, and reduction in overall severity correlated with perceived breathiness.

Conclusions: Although individuals varied in their outcomes, group results suggest that response to RLN lidocaine block warrants further study as a possible diagnostic tool in ADSD.

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