Vocal Fold Paralysis (Vocal Cord Paralysis) Etiologies

see also: Vocal Cord Paralysis Evaluation and Etiology

return to: Unilateral Laryngeal Paralysis or Vocal Cord Paralysis

see also: Wallenberg Syndrome PICA Syndrome Lateral Medullary Infarction, Tapia Syndrome paralysis of vagus and hypoglossal nerves after intubation;

Vernet's Syndrome (Juguloforamen Syndrome) Laryngeal paralysis

"Vocal fold paralysis is not a rare clinical entity." Sulica and Blitzer 2006

1. Extent of Problem
   1. Overall incidence/prevalence of laryngeal paralysis in the United States and the world is not known. Difficulties in determining this information include
      1. Detection of laryngeal paralysis requires imaging of the larynx 
         1. usually by indirect mirror exam, transoral rigid video-endoscopy, or transnasal flexible laryngoscopy (either fiberoptic or distal chip)
         2. alternative approaches exist - including ultrasound and evaluation under general anesthesia with rigid direct laryngoscopy
         3. even with clear imaging of the larynx (not always possible due to anatomic restraints) interpretation of findings may be difficult
            1. Movement of adjacent structures may make vocal cord appear mobile
            2. Repeated viewing of video-recordings by different observers often result in different interpretation
            3. Varying degrees of vocal fold paralysis (paresis) may result in minor degrees of movement confounding the diagnosis of true paralysis
            4. Other causes of decreased vocal fold mobility need to be factored in (scarring from reflux/intubation; rheumatoid fixation of arytenoid)
      2. Detection of laryngeal paralysis by reporting of symptoms by the patient  (without examining the larynx) markedly under estimates the extent of the problem
         1. Misdiagnosis
            1. Dysphonia has many causes -- dysphonia from laryngeal paralysis is often ascribed to other disorders (i.e. reflux, muscle tension dysphonia)
            2. Shortness of breath due to unilateral or bilateral laryngeal paralysis has been ascribed to disorders such as asthma 
         2. Perceived impairment of voicing problems may preclude full evaluation relative to other disorders associated with the paralysis
            1. The dysphonia associated with laryngeal paralysis caused by malignancy may be discounted in view of the greater morbidity and potential mortality of a lung cancer or other process
            2. Focus on attention to other medical problems may triage dysphonia to a problems whose evaluation (with laryngeal imaging) is deferred
         3. Cases of laryngeal paralysis occurring in patient with good vocal fold position and good pulmonary function may escape detection due to lack of perception of symptoms
   2. Surgical management of unilateral laryngeal paralysis
      1. A survey of cases Otolaryngologists in the United States by Rosen C (1998)
         1. 33% response rate from mail survey to 7,364 Otolaryngologists (n= 2,436)
         2. 43% performed medialization thyroplasty (defined as thyroplasty or arytenoid adduction - performed separately or concurrently)
         3. Number of procedure (open medialization procedures) reported in this study = 14,621
      2. Followup survey of Otolaryngologists in the United States (Young et al 2010)
         1. 25.7% response rate from mail survey to 6,644 Otolaryngologists (n= 1,707)
         2. 63% performed medialization thyroplasty (defined as thyroplasty or artyenoid addcution -perforemd separately or concurrently)
         3. Number of procedures (open medialization procedures) reported in this study done between 1998- 2008 = 29,748
      3. Perspective from thyroid surgery
         1. Well differentiated thyroid cancer responsible for 50% of the 80,000 thyroidectomies done in the U.S. annually (Francis D et al 2014)
            1. Review of SEER-Medicre data by Francis et al identified 5,670 total thyroidectomies for WDTC (1991-2009)
               1. 9.5% complicated by vocal fold paralysis (8.2% unilateral; 1.3% bilateral)
               2. 22% of patients with vocal fold paralysis were treated surgically (UVFP 21%, BVFP 28%)
         2. Between 118,000 and 166,000 patients in the United States undergo thyroidectomy per year for benign or malignant disease. Chandrasekhar S (2013)
            1. About 1 in 10 patients expereience temporary laryngeal nerve injury after surgery with longer lasting voice prooblems in upto 1 in 25.  
      4. Perspective from cervical spine surgery (anterior approach Tan, 2014)
         1. Review article identifies vocal cord paralysis to be a significant morbidity after anterior cervical spine surgery with incidence up to 24.2% in the immediate postoperative period.
         2. Increased risk of postop vocal cord paralysis includes: reoperation and right-sided surgical approach. 
2. Etiology of Laryngeal Paralysis
   1. Most commonly reported for unilateral laryngeal paralysis
      1. Demographics continually changing
      2. Increasing numbers associated with surgical procedures (below adapted from Sulica L et al 2006)

2. Nonsurgical causes of laryngeal paralysis
   1. Idiopathic
   2. Tumor involvement
   3. Non-tumor involvement (ie Ortner's syndrome)

References:

Sulica L, and Blitzer A: Preface in  Vocal Fold Paralysis ed Sulica L and Blitzer A  Springer  New York  2006

Rosen C: Complications of PHonosurgery: Results of a National Survey. Laryngoscope, 1998, Nov 108:11 part 1 pp 1697-1703

Young V, Zullo T, and Rosen C: Analysis of Laryngeal Framework Surgery: 10- Year Follow-up to a National Survey. Laryngoscope, 120:1602-1608, 2010

Francis D, Pearce E, Ni S, Garrett CG, and Penson D: Epidemiology of Vocal fold Paralyses after Total Thyroidectomy for Well-Differentiated Thyroid Cancer in a Medicare Population. Otolaryngology Head and Neck Surgery 2014 (online publicatoin Jan 30 2014  

Chandrasekhar S, Randolph G, Seidman M et al Clincial Practice Guideline: IMproving Voice Outcomes after thyroid Surgery. Otolaryngology–Head and Neck Surgery 148(65)S1-S37 2013  

Sulica L, Cultrara A, and Blitzer A: Vocal Fold Paralysis: Causes, outcomes, and Clinical Aspects. Chapter 3 in Vocal Fold Paralysis ed Sulica L and Blitzer A  Springer  New York  2006