Evaluation of Peripheral Vocal Cord Paralysis by Electromyography

Authors

  • Maria Grosheva MD,

    1. From the Department of Otorhinolaryngology, Head and Neck Surgery, Worldwide Headquarters, Innsbruck, Austria
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  • Claus Wittekindt MD,

    Corresponding author
    1. From the University of Cologne, Germany; the Department of Otorhinolaryngology, Worldwide Headquarters, Innsbruck, Austria
    • Send correspondence to Dr. Claus Wittekindt, Department of Otorhinolaryngology, Friedrich Schiller-University Jena, Lessingstrasse 2, 07740 Jena, Germany
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  • Claus Pototschnig MD,

    1. From the Department of Otorhinolaryngology, Head and Neck Surgery, Worldwide Headquarters, Innsbruck, Austria
    2. From the Friedrich-Schiller-University Jena, Germany; the Department of Otorhinolaryngology, Worldwide Headquarters, Innsbruck, Austria
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  • Werner Lindenthaler MD,

    1. From the Department of Otorhinolaryngology, Head and Neck Surgery, Worldwide Headquarters, Innsbruck, Austria
    2. From the Leopold-Franzens University of Innsbruck, Innsbruck, Austria; and MED-EL Medical Electronics, Worldwide Headquarters, Innsbruck, Austria
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  • Orlando Guntinas-Lichius MD

    1. From the University of Cologne, Germany; the Department of Otorhinolaryngology, Worldwide Headquarters, Innsbruck, Austria
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  • Editor's Note: This Manuscript was accepted for publication January 3, 2008.

Abstract

Objective: To analyze the predictive value of electromyography (EMG) after peripheral vocal cord paralysis and to estimate regeneration time.

Study Design: Retrospective study based on electromyographic data and medical chart review of university based ENT hospitals.

Methods: EMG results of 448 patients were classified into neuropraxia, axonotmesis/neurotmesis, or not classifiable and followed until final outcome. Final outcome was classified electromyographically into restitutio ad integrum, defective healing, or not classifiable.

Results: The etiology of the paralysis was thyroid gland surgery in 42.9% and other iatrogenic lesions in 11.8%. Idiopathic paralysis was found in 20.3%. Mean follow-up time was 4.8 months. Initial EMG findings were neuropraxia in 31.0%, axonotmesis/neurotmesis in 40.8%, and not classifiable in 28.1%. Restitutio ad integrum was detected by EMG in 17.6% and defective healing in 43.3%. In 39.1%, the outcome could not be classified. The positive predictive value of EMG was 97% and the negative predictive value 60%. The outcome depended significantly on the initial EMG result (P < .0001) but not on the etiology (P = .737) of the paresis. Regeneration time after neuropraxia was 4.0 months and after axonotmesis/neurotmesis 5.6 months.

Conclusion: Laryngeal EMG has a high predictive value for acute peripheral vocal cord paralysis. The outcome can be predicted more reliably by means of EMG than by analysis of the etiology of the lesion.

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