title: Single institutional analysis of trends over 45 years in etiology of vocal fold paralysis.
abstract: OBJECTIVE
  It is important to assess the causes of vocal fold paralysis. Many studies have reported causes of paralysis, but few reports have shown changes in longitudinal etiology in a single institution.
  
  
  METHODS
  We investigated the medical records of 797 patients with vocal fold paralysis from 1990 to 2005 at the voice and bronchoesophageal outpatient clinics at the University of Tokyo Hospital. We evaluated the etiology of paralysis, and compared our results with a previous study by Hirose in our clinic from 1961 to 1989 to assess changes in etiology.
  
  
  RESULTS
  The postoperative group comprised 466 patients (58.5%), while the non-surgical group comprised 331 (41.5%) patients. In the postoperative group, the most common cause of paralysis was thyroid surgery (106 cases), and other common causes were surgery for aortic aneurysm (61 cases) and tracheal intubation (58 cases). In the non-surgical group, idiopathic paralysis (134 cases) was the most common cause. Other common causes were lung cancer (34 cases) and cerebrovascular disease (24 cases). In a previous study from our clinic, the rate of postoperative paralysis was 43.5%. In the current analysis, the percentage of postoperative patients has increased remarkably compared with that of the previous report while the rate of idiopathic paralysis, has decreased by half.
  
  
  CONCLUSIONS
  The increase in postoperative cases of paralysis may be caused by the increasing frequency of operations for many diseases, due to the progress of medical techniques in recent years. The decrease in idiopathic cases may be related to the advances of diagnostic devices such as CT and MRI.
authors.affiliation: Department of Otorhinolaryngology, Head & Neck Surgery, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku, Japan. stakano@hosp.ncgm.go.jp
authors.forename: Shingo
authors.initials: S
authors.lastname: Takano
authors.forename: Takaharu
authors.initials: T
authors.lastname: Nito
authors.forename: Noriko
authors.initials: N
authors.lastname: Tamaruya
authors.forename: Miwako
authors.initials: M
authors.lastname: Kimura
authors.forename: Niro
authors.initials: N
authors.lastname: Tayama
mesh_terms: D000328:Adult; D000368:Aged; D001014:Aortic Aneurysm / Q000601:surgery; D002561:Cerebrovascular Disorders / Q000150:complications; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000009:adverse effects; D008137:Longitudinal Studies; D008175:Lung Neoplasms / Q000150:complications; D008297:Male; D008875:Middle Aged; D012009:Recurrent Laryngeal Nerve / Q000503:physiopathology*; D012189:Retrospective Studies; D013965:Thyroidectomy / Q000009:adverse effects; D014826:Vocal Cord Paralysis / Q000209:etiology*