eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > Laryngology

Vocal Fold Paralysis, Unilateral

Author: Thomas L Carroll, MD, Assistant Professor, Department of Otolaryngology-Head and Neck Surgery, Tufts Medical Center, Tufts University School of Medicine
Coauthor(s): Clark A Rosen, MD, Director, University of Pittsburgh Voice Center; Associate Professor, Department of Otolaryngology and Communication Science and Disorders, University of Pittsburgh School of Medicine; Ryan J Soose, MD, Assistant Professor, Department of Otolaryngology, University of Pittsburgh Medical Center
Contributor Information and Disclosures

Updated: Nov 6, 2008

Introduction

Unilateral vocal fold paralysis (UVFP) occurs from a dysfunction of the recurrent laryngeal or vagus nerve innervating the larynx. It causes a characteristic breathy voice often accompanied by swallowing disabilty, a weak cough, and the sensation of shortness of breath. This is a common cause of neurogenic hoarseness. When this paralysis is properly evaluated and treated, normal speaking voice is typically restored.

History of the Procedure

Unilateral vocal fold paralysis (UVFP) most commonly occurs following a surgical iatrogenic injury to the vagus or recurrent laryngeal nerve. Thus, a history of head and neck, skull base, brainstem or chest surgery should be obtained. Specifically, thyroidectomy, carotid endarterectomy, anterior cervical spine surgery, thoracic, or mediastinal surgery most often result in a presentation of unilateral vocal fold paralysis (UVFP).

The differential diagnosis for an acute unilateral vocal fold paralysis (UVFP) should always include recent upper respiratory tract or viral infection and recent intubation for any surgical procedure. Procedures aimed at restoring glottic competence include permanent and temporary vocal fold injections, as well as laryngeal framework surgery, including medialization laryngoplasty (type 1 thyroplasty) and arytenoid adduction or arytenopexy.

Problem

Normal vocal fold function is reliant on vocal fold glottal closure that results from bilateral adduction of the vocal folds. Normally, this vocal fold adduction behavior, in combination with subglottic airflow, induces vocal fold vibration. Unilateral vocal fold paralysis (UVFP) results in glottal incompetence, either partial or complete, resulting in a weak or absent vocal fold vibration that leads to dysphonia. Significant muscle tension is often seen in the larynx as a compensatory mechanism for the glottal gap. Patients with unilateral vocal fold paralysis (UVFP) often describe pain in the throat or neck after voice use, which is likely due to the excessive muscle tension. 

Etiology

  • Surgical iatrogenic injuries resulting in vocal fold paralysis include thyroid surgery, anterior cervical disc surgery, carotid surgery, or chest surgery.
  • Malignant invasion of either the vagus or recurrent laryngeal nerve can occur with skull base tumors, thyroid cancer, lung cancer, esophageal cancer, and metastases to the mediastinum (often observed with lung cancer primaries).
  • Blunt trauma to the neck or chest.
  • When a clear-cut etiology for the unilateral vocal fold paralysis (UVFP) is not found, it is classified as idiopathic. These cases can be attributed to a viral or inflammatory process, but this is usually a presumptive diagnosis.

Pathophysiology

The recurrent laryngeal nerve is responsible for both abduction and adduction of the vocal fold. The recurrent laryngeal nerve originates from the vagus nerve, which originates from the brainstem (nucleus ambiguous in the medulla) and travels along the carotid sheath (with the jugular vein and internal carotid artery). The left vagus nerve gives rise to the left recurrent laryngeal nerve as the vagus crosses the arch of the aorta. The left recurrent laryngeal nerve then loops under the ligamentum arteriosum and travels cephalad in the tracheoesophageal groove until it penetrates the larynx to innervate the intrinsic muscles of the larynx. The right vagus nerve delivers the recurrent laryngeal nerve branch at the level of the subclavian artery. The right recurrent laryngeal nerve loops around the subclavian artery and proceeds cephalad to the larynx.

The recurrent laryngeal nerve, just prior to its entrance into the larynx, runs deep to the inferior cornu of the thyroid cartilage. For a short section, the nerve is in a space between the cricoid and thyroid cartilage. This is thought to be the space where the nerve is vulnerable to compression from the cuff on an endotracheal tube that is either overinflated or positioned too far cephalad. Because of the circuitous nature of the recurrent laryngeal nerve, multiple disease processes and operative procedures put these important nerves at risk, often resulting in vocal fold paralysis.

Presentation

Patients with unilateral vocal fold paralysis (UVFP) typically present with a fairly sudden onset of breathy, weak, low-pitched dysphonia. In some cases, however, the dysphonia can be high-pitched because of a compensated lengthening of the vocal folds to achieve better glottic closure. Often, unilateral vocal fold paralysis (UVFP) is associated with dysphagia, specifically with liquids, because the resultant glottal incompetence can lead to aspiration. This is especially true if the unilateral vocal fold paralysis (UVFP) is due to a high vagal lesion that results in both a recurrent laryngeal nerve and superior laryngeal nerve palsy. The latter results in significant anesthesia of the pharynx, contributing to the patient's dysphagia and increased risk for aspiration.

Patients with unilateral vocal fold paralysis (UVFP) often report shortness of breath or a feeling of running out of air. Very little negative physiological impact upon pulmonary function actually occurs in patients with unilateral vocal fold paralysis (UVFP); however, because of the glottal incompetence, they experience significant air wasting and, thus, experience the sensation of shortness of breath and running out of air during speech. In addition, glottal closure is required for individuals to create positive end expiratory pressure (PEEP). Thus, some patients with an immediate postoperative unilateral vocal fold paralysis (UVFP) can experience decreased pulmonary function because of loss of the natural PEEP that occurs with glottal closure. The glottic closure that allows a forceful cough is also compromised and thus a weak, unsuccessful cough is often reported by patients.

Indications

The indications for treatment of unilateral vocal fold paralysis (UVFP) are usually the resultant dysphonia or an ineffective cough in a patient at risk for aspiration or pulmonary compromise. Treatment may be more imperative if severe dysphagia is present. If patients experience dysphagia, then they are at risk for aspiration pneumonia and treatment should be implemented immediately.

For dysphonia related to unilateral vocal fold paralysis (UVFP), treatment should be determined based on the patient's functional needs and demands. Some patients do not notice any significant functional limitation related to their unilateral vocal fold paralysis (UVFP). This minimal functional limitation results because of the person's minimal voice demands or comorbidities that occur during postoperative recovery. A temporary injection is often given to allow for an immediate return of glottic competence while the nerve potentially recovers. Electromyelography (EMG) can be used to determine the prognosis of RLN recovery, even if a temporary injection has occurred. If motion does not return and serial laryngeal electromyography shows no chance for meaningful recovery of vocal fold motion, then a permanent injection of fat, a semipermanent injection of calcium hydroxylapatite, or a medialization laryngoplasty can be offered.

In addition to patient history regarding functional aspects of voice use and voice demands, a standardized voice-related outcome measure can be used to assess the patient's vocal limitations and disability. The voice handicap index has been shown to be a reliable and useful patient-based survey instrument, quantifying the patient's voice handicap due to their voice disorder.

Note that the indications for treatment are related to the patient's function and limitations. Nonsurgical treatment can be offered to patients with unilateral vocal fold paralysis (UVFP), especially those who are unwilling or unable to proceed with surgical treatment.

Relevant Anatomy

The anatomy of the vagus/recurrent laryngeal nerve has been outlined above (see Pathophysiology), and its understanding is crucial to the evaluation of the potential etiology for patients who present with unilateral vocal fold paralysis (UVFP).

An understanding of both the internal and external laryngeal anatomy is important for the surgical treatment of unilateral vocal fold paralysis (UVFP). For patients who receive a vocal fold injection, an appreciation and thorough understanding of the anatomy of the membranous vocal fold, vocal process of the arytenoid cartilage, and paraglottic space is crucial for successful treatment.

Laryngeal framework surgery for the treatment of unilateral vocal fold paralysis (UVFP) requires an understanding of the relationship and anatomy of the thyroid cartilage and cricoid cartilage. This is especially true regarding the relationship of the membranous vocal fold and paraglottic space to the external landmarks of the thyroid cartilage. For the more advanced laryngeal framework surgery techniques (eg, arytenoid adduction, cricothyroid subluxation), thorough knowledge of the anatomy of the cricothyroid joint and cricoarytenoid joint are required to be successful.

Contraindications

No contraindications exist for the nonsurgical treatment of unilateral vocal fold paralysis (UVFP) other than the patient not indicating or realizing the need for treatment. Contraindications for the surgical treatment of unilateral vocal fold paralysis (UVFP) can include medical problems, such as severe cardiac or pulmonary limitations, or anticoagulation therapy. Although more risky and not ideal, injection of an anticoagulated patient has been routinely performed successfully in our practice. Performing injections on a patient via a transoral or transcutaneous route under local or MAC anesthesia can also be done routinely in the riskier patient.  

A careful and detailed medical history and evaluation are required prior to deciding on surgical treatment for unilateral vocal fold paralysis (UVFP). Often, the most complete history is obtained in conjunction with an internal medicine physician and an anesthesiologist. A poorly abducting contralateral vocal fold is a relative contraindication for surgical treatment of unilateral vocal fold paralysis (UVFP) because of the airway reduction that occurs with surgical medialization of the paralyzed vocal fold.

More on Vocal Fold Paralysis, Unilateral

Overview: Vocal Fold Paralysis, Unilateral
Workup: Vocal Fold Paralysis, Unilateral
Treatment: Vocal Fold Paralysis, Unilateral
Follow-up: Vocal Fold Paralysis, Unilateral
Multimedia: Vocal Fold Paralysis, Unilateral
References
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References

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  2. Zeitels SM, Hillman RE, Desloge RB, et al. Cricothyroid subluxation: a new innovation for enhancing the voice with laryngoplastic phonosurgery. Ann Otol Rhinol Laryngol. Dec 1999;108(12):1126-31. [Medline].

  3. Amin MR. Thyrohyoid approach for vocal fold augmentation. Ann Otol Rhinol Laryngol. Sep 2006;115(9):699-702. [Medline].

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Further Reading

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Keywords

unilateral vocal fold paralysis, UVFP, vocal cord paralysis, neurogenic hoarseness, vocal cord paralysis, larynx, neurogenic hoarseness

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Contributor Information and Disclosures

Author

Thomas L Carroll, MD, Assistant Professor, Department of Otolaryngology-Head and Neck Surgery, Tufts Medical Center, Tufts University School of Medicine
Thomas L Carroll, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Otolaryngology-Head and Neck Surgery, and American Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Clark A Rosen, MD, Director, University of Pittsburgh Voice Center; Associate Professor, Department of Otolaryngology and Communication Science and Disorders, University of Pittsburgh School of Medicine
Clark A Rosen, MD is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Medical Association, and Pennsylvania Medical Society
Disclosure: Bioform Medical  Consulting fee Consulting

Ryan J Soose, MD, Assistant Professor, Department of Otolaryngology, University of Pittsburgh Medical Center
Ryan J Soose, MD is a member of the following medical societies: Alpha Omega Alpha and Phi Beta Kappa
Disclosure: Nothing to disclose.

Medical Editor

John Schweinfurth, MD, Associate Professor, Department of Otolaryngology, University of Mississippi Medical Center
John Schweinfurth, MD is a member of the following medical societies: American Academy of Otolaryngic Allergy, American Academy of Otolaryngology-Head and Neck Surgery, and American Medical Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Robert M Kellman, MD, Professor and Chair, Department of Otolaryngology and Communication Sciences, State University of New York, Upstate Medical University
Robert M Kellman, MD is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, American College of Surgeons, American Medical Association, American Neurotology Society, American Rhinologic Society, American Society for Head and Neck Surgery, Medical Society of the State of New York, and Triological Society
Disclosure: GE Healthcare Honoraria Review panel membership

CME Editor

Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders
Christopher L Slack, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Medical Association
Disclosure: Nothing to disclose.

Chief Editor

Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine
Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Head and Neck Society
Disclosure: Covidien Corp Consulting fee Consulting; US Tobacco Corporation unstricted gift unknown; Axis Three Corporation Ownership interest Consulting; Omni Biosciences Ownership interest Consulting; Sentegra Ownership interest Board membership; Syndicom Ownership interest Consulting; Oxlo  Consulting; Medvoy Ownership interest Management position

 
 
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